Tiêm Botulinum Toxin Trong Thực Hành Thẩm Mỹ (Tập 2): Giải Phẫu Chức Năng Và Kỹ Thuật Tiêm

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
243
nasolabial fold and also converges at the modiolus.15,17 The facial
artery courses along the lateral side of the modiolus to terminate into
the angular artery after the superior labial artery branches off from
it, while supplying the blood to the modiolus and the perioral region.
This artery conveniently delineates the anterior limit of the buccal fat
pad located at the lateral edge of modiolus which are both anatomi­
cally in the same plane. Conversely, the buccal fat pad is posterior to
the facial vein and separated from the vein by the facial-vein canal.
The fat present there is the fat within the buccal space. A large tro­
phic modiolus with a large quantity of converging muscular fibers
consequently can maintain the buccal fat pad in its original posi­
tion and prevent it from descending and protruding with age.13,15
Likewise, a well-controlled modiolus plays an important role of inte­
grating the activities of the lips, the oral fissure and vestibule, cheeks,
and jaws by the muscles that comprise it. There can be up to nine
muscles which interlace and decussate within the modiolus, includ­
ing: the zygomaticus major, platysma pars modiolaris, levator anguli
oris, mentalis (sometimes), depressor labii inferioris (rarely), depres­
sor anguli oris, risorius, and the main functional sphincteric effec­
tors, the orbicularis oris and buccinator.17 The muscles lie in different
planes, their modiolar stems often form spirals, and most of them
divide into two, three, or four bundles, each of them interlacing and
attaching in diversely distinctive ways. Because of the high degree
of three-dimensional functional complexity and individual patient
anatomical and racial diversity, verification of modiolar functional
anatomy and its location as a fixed, specific anatomical focal point
cannot always be confirmed. In general, the modiolus has the overall
configuration of a blunt kidney-shaped cone (Figure 15.7). Its base
(basis moduli) is adjacent and adherent to the buccal mucosa. In
Caucasians and Africans, it is generally located approximately 2 cm
lateral to the center of the oral commissure and measures about 2 cm
above and below an imaginary horizontal line that passes through
the center of the oral commissure (cheilion). From mucosa to dermis,
its vertical thickness is approximately 1 cm. In Asians, the modiolus
is found less than 1.5 cm lateral and approximately 1.0 cm below the
horizontal line bisecting the cheilion.18 The cone-shaped modiolus is
extended by two rounded edges or cornua, which gives it its kidney
shape and which extends into the lateral tissue of the free lip margin,
above and below the angle of the mouth (Figure 15.7).
A set of suitably trophic modioli are required for the common three-
dimensional mimetic muscular movements performed either bilater­
ally and symmetrically or unilaterally and asymmetrically. It is the
modiolus that enables one to integrate common routine movements
of the cheeks, lips, jaws, oral aperture, and vestibule. The modioli are
responsible for monitoring changes in oral vestibular contents and
controlling the pressure within the oral cavity. The modioli facilitate
the innumerable precise variations in fine motor movements involved
in speech and word formation, as well as the generation of abrasive
harsh sounds and the modulation of harmonious musical tones and
delicate soft whispers. They also bolster various deliberate activities
such as biting, screaming, shouting, crying, chewing, drinking, spit­
ting, sucking, swallowing, and whistling. All the permutations of
facial expression, ranging from mere hints of satisfaction, elation, or
purposeful determination to exaggerated distortions of sadness, pain,
and discontent, be they symmetrical or asymmetrical, are enabled by
the intricately synergistic and precise displacements of the modio­
lus.17 These complicated modiolar movements are partly made pos­
sible because of the three muscular levels or strata of modiolar muscle
insertions: the buccinator, levator anguli oris, and zygomaticus major.
Many of the movements of the modiolus seem to involve most, if
not all, of its associated nine muscles (see above), whose actions are
predicated on the amount of separation between the upper and lower
teeth (i.e., the gape of the mouth). As the interlabial and interden­
tal distances approach their maximum separation of about 4 cm, the
modiolus occupies the interdental space, moves anteriorly 1 cm closer
to the oral commissure, and becomes immobile. With the mouth wide
open, the nasolabial sulci elongate, becoming straighter and more
vertical, and the inferior labiomandibular sulci (marionette lines)
are less deep and curved. With the lips in contact with each other
and the teeth in tight approximation, the modiolus can move only
a few millimeters in all directions. The mobility of the modiolus is
maximized when the upper and lower teeth are separated by 2–3 mm,
similar to its position when speaking. The muscular modiolar activi­
ties are enhanced by the partial separation of the jaws, integrating
buccal functional movements with the direct labial retractors (leva­
tors of the upper lip and depressors of the lower lip) (Figure 15.8b).
All of the delicate but intricate movements of the lips and mouth can
be either intentionally or involuntarily set into motion from moment
to moment by subtle and expeditious contractions of the diversely
complex mimetic muscles of the perioral area.
A considerable number of the modiolar stem fibers are directly
reinforced by different muscle fibers originating from the buccinator,
an accessory muscle of mastication, which also reinforces the strati­
fied complex of deeper intrinsic muscle fibers of the orbicularis oris.
The buccinator in reality is not a typical mimetic muscle of the face.
It is a deep, thin, quadrilateral muscle that spans the void between
the maxilla and mandible and forms the deep muscular boundaries
of the cheek (Figure 15.8b). Its posterior origins are from the outer
surfaces of the alveolar processes of both the maxilla and mandible
at the junction of the mandibular body and ramus, just posterome­
dial to the last molar and at the pterygomandibular raphe and liga­
ment (Figure 15.10). This raphe stretches from the medial pterygoid
process to the inner surface of the mandible, and represents the line
of juncture between the buccinator and the superior constrictor of the
pharynx (Figures 15.8b and 15.10). The buccinator is composed of four
fibrous bands of muscle: a superior band originating from the maxilla,
a central band extending from the pterygomandibular raphe, and two
inferior bands of muscles extending from the mandible. The superior
1
2
3
Figure 15.9  1, Depressor labii inferioris; 2, depressor anguli oris; 3, platysma, pars
labialis occupying any vacant space between muscles 1 and 2.

Botulinum Toxins in Clinical Aesthetic Practice
244
muscle band spreads anteriorly from behind the third maxillary molar
to occupy the submucosa of the cheek and lips, as well as to converge
into the modiolus. Also at the modiolus the central pterygomandibu­
lar fibers of the buccinator intersect and decussate with the orbicularis
oris. The two inferior mandibular bands of the buccinator fibers from
below cross to the upper part of the orbicularis oris, and those from
above cross to the lower part of the orbicularis oris, crisscrossing each
other as they continue on to their insertions in the upper and lower
lips. However, the highest (maxillary) and lowest (mandibular) fibers
of the buccinator continue forward to enter their corresponding upper
and lower lips in a purse string fashion without decussating with the
orbicularis oris (Figure 15.8b). As the buccinator courses through the
cheek and modiolus, substantial numbers of its fibers are diverted
internally to attach to the buccal submucosa.4
The buccinator’s function is to keep the cheek against the gums
and teeth during mastication. It also keeps food in between the teeth
and prevents it from becoming lodged in the sulcus between the teeth
and cheek. It also assists the tongue in directing and maintaining
food between the teeth while chewing. As the mouth closes, the teeth
glide over the buccolabial mucosa, which must be continuously and
progressively retracted away from the occlusal surfaces of the teeth,
otherwise a person would constantly inadvertently bite down on the
inner surface of the buccal mucosa.
Contraction of the buccinator also prevents the cheeks from becom­
ing overly distended by positive pressure when air, liquid, or solids fill
the oral cavity. The buccinator assists in gradually expelling from in
between the lips accumulated liquid, solids, or air within the oral cav­
ity, as when spitting, blowing up a balloon, or playing a musical wind
instrument (buccinator is Latin for trumpet player)4 (Figure 15.8b).
Superficial to those deep intrinsic muscle fibers of the buccinator
and orbicularis oris is another stratum of muscle fibers formed on
either side of the mouth by the levator anguli oris and the depressor
anguli oris. The fibers of both the levator and depressor crisscross each
other at the corners of the mouth and continue away from each other.
The muscle fibers of the levator anguli oris continue inferiorly into the
lower lip and insert into the skin near the midline of the lower lip. The
muscle fibers of the depressor anguli oris follow the same pattern into
the upper lip, inserting into the skin at the midline. Reinforcing these
superficial transverse fibers of the upper and lower lips are interdigitat­
ing oblique muscle fibers from the levator labii superioris, the zygo­
maticus major, and the depressor labii inferioris. In addition, there are
the intrinsic orbicularis oris muscle fibers of the lips, which run in an
oblique direction and pass from the undersurface of the skin through
the thickness of the lip and into the mucous membrane. Finally, there
are additional slips of muscle fibers of the orbicularis oris which attach
to the alveolar process of the maxilla, the nasolabial sulcus, and the
nasal ala and septum superiorly and the alveolar process of the man­
dible inferiorly, anchoring the orbicularis oris in place as high as the
nose and nasolabial folds, and as low as the mentolabial sulcus.
Dilution When Treating Perioral Lip Lines and Rhytides
(see Appendix 3)
Injections of OnaBTX-A into the lips and the orbicularis oris must be
done intradermally and with minimal dosing.19 Because there may be
1
2
3
4
5
6
7
8
9
10
11
12
13
Figure 15.10  The anterior lateral and internal medial aspects of the mandible with its various topographical landmarks: 1, alveolar process; 2, mental protruberance; 3,
mental tubercle; 4, mental foramen; 5, body; 6, angle; 7, ramus; 8, mandibular condyle; 9, head; 10, mandibular notch; 11, coronoid process; 12, neck; 13, mandibular con­
dyle. (Adapted from Brennan PA, Mahadevan V, Evans BT, Clinical Head and Neck Anatomy for Surgeons, CRC Press: Boca Raton, FL, 2016, with permission.)
Figure 15.11  Injections of OnaBTX-A into the orbicularis oris at the junction
between the upper pars marginalis and pars peripheralis in this 59-year-old patient
were very painful.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
245
a multitude of vertical lines across the lips, concentrated OnaBTX-A
will not spread readily across the expansive surface of the superficial
fibers of the orbicularis oris. To have the OnaBTX-A spread evenly,
one can reconstitute a 100 U vial of OnaBTX-A with anywhere from
2 to 4 mL of normal saline. In this way, when injected intradermally,
dilute, large volumes of OnaBTX-A can spread across the surface of
the superficial fibers of the orbicularis oris even when only 1 or 2 U of
OnaBTX-A are injected into each quadrant of the pars peripheralis of
the upper and lower lips. Applying OnaBTX-A intradermally and in
low doses will avoid any compromise in the sphincteric and synergis­
tic functions of the deeper muscle fibers of both the orbicularis oris
and the labial retractors and evertors.20,21 However, there are those
veteran expert injectors that are still using the same 100-unit vial of
OnaBTX-A that was reconstituted with 1 mL of normal saline to treat
perioral lip lines and rhytides.
Dosing: How to Correct the Problem (see Appendix 4), (What to
Do and What Not to Do) When Treating Perioral Lip Lines and
Rhytides
Because of the complex nature of the orbicularis oris and the way
it functions, injections of OnaBTX-A in the perioral area should be
performed only by an experienced physician injector. Each patient
should be evaluated and treated individually and standard injection
points should not necessarily be adhered to in this area or any other
area of the face. OnaBTX-A should be injected into an area of maxi­
mal muscle contraction, indicated by the deepest vertical rhytides.
This is particularly important in the lips where the vertical lip lines
may not be exactly symmetrical and do not always appear at the same
depth or location in every patient. Perioral rhytides are dependent on
the particular strength of the various superficial fibers of the orbicu­
laris oris at that location (i.e., in that quadrant), which can vary from
one patient to the next.
Place properly selected patients in the upright sitting or semire­
clined position and inject 1–2 U of OnaBTX-A into each pars periphe­
ralis of the upper and lower lips intradermally and no deeper than
the dermosubcutaneous junction. At this level, the superficial fibers
of the orbicularis oris can be found. The appearance of fluid-filled
wheals confirms the injections are performed at the proper depth.
Injections can be placed into the border between the pars periphera­
lis and pars marginalis, which is the only location where the muscle
fibers of both partes meet and insert into the dermis, the so-called
“hockey stick” point of the vermilion border1 (Figure 15.8b). This
technique can be more painful than when OnaBTX-A is injected into
the pars peripheralis 2 and no more than 4 mm away from the vermil­
lion border of the upper and lower lips (Figure 15.12).
A further refinement of the injection technique is to stand behind
the patient (Figure 15.13a,b). Reach around the patient’s head with the
nondominant hand and grasp the lip betweent the thumb and index fin­
ger, moderately squeezing the lip to distract the patient. The slight dis­
comfort experienced by the patient when the lip is compressed between
the fingers will help distract the patient from feeling the full impact of
the pain experienced when the lips are pierced by the needle and the
(a)
(b)
(c)
(d)
Figure 15.12  (a–d) Injections of OnaBTX-A placed 2–4 mm above the vermilion border into the center of the pars peripheralis of the orbicularis oris were less painful for
this 53-year-old patient. (Same patient as in Figure 15.5.)

Botulinum Toxins in Clinical Aesthetic Practice
246
OnaBTX-A fluid is injected. Approaching the lip from behind on the
opposite side of the head and from above the upper lip, pierce the skin of
the cutaneous lip with a 30- or 31-gauge needle at less than a 45-degree
angle, 2–4 mm above the vermilion border. Advance the needle tip
downward to just underneath the lip’s “white roll” of the vermilion
border, that is, the “hockey stick” point. While simultaneously squeez­
ing the lip a little harder with the thumb and index finger of the non­
dominant hand, inject intradermally only 1 or 2 units of OnaBTX-A.
Injections must be intradermal to affect only the superficial fibers of the
orbicularis oris and to avoid deeper fibers of the upper lip retractors and
inadvertent complications. The more superficial the injection, the more
painful the injection, no matter what product is injected or where on
the lip it is placed. Repeat this “squeeze and inject” maneuver all around
the lips. However, when injecting the lower lip, return from behind the
patient and stand facing the patient. Grasp the lower lip between the
thumb and index finger with the nondominant hand. Approach the
patient from below the lower lip. Pierce the cutaneous lip with a 30-
or 31-gauge needle at less than a 45-degree angle, 2–4 mm below the
vermilion border. Advance the needle tip upward to just underneath
the “white roll” border of the vermilion and cutaneous lip. Squeeze a
little harder and inject 1 or 2 units of OnaBTX-A (Figure 15.13c,d). It
is recommended that, at the initial treatment session, both quadrants
of the pars peripheralis of the upper and lower lips be treated with no
more than 2 U of OnaBTX-A. Inject each quadrant intradermally and
symmetrically into 1–3 points per quadrant, depending on the severity
of the wrinkling. The upper lip should not be injected with more than
10 U of OnaBTX-A at any given treatment session. OnaBTX-A should
not be injected directly into the center of the philtrum, to avoid flatten­
ing of the philtral columns. If the lower lip does not possess the same
type of deep rhytides as the upper lip, the lower lip still needs to be
treated, but with only minimal amounts of OnaBTX-A, that is, no more
than 2 units in each quadrant for a total of 4 U in the entire lower lip,
(a)
(b)
(c)
(d)
Figure 15.13  (a,b) Injection technique of the upper lip. Note the position of the fingers, compressing the lip between the index finger and thumb of the non-dominant hand.
The approach is from behind the patient. The needle is inserted into the cutaneous lip 2–4 mm above the vermilion and then advanced under the vermillion raising a wheal
with the injection. (c,d) Returning to the front of the patient, the injection technique is the same.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
247
especially at the initial treatment session. It is advisable always to treat
the lips symmetrically. By injecting the upper and lower lips in the four
quadrants of the pars peripheralis at the same time, the orbicularis oris
will weaken in a relatively proportionately symmetrical manner. This
will allow the perioral muscles to adapt more easily to the subsequent
changes in perioral muscle strength and proprioception, thereby main­
taining the necessary and normal perioral functional competence of the
overall sphincteric action of the lips.21 The dose in each quadrant can
vary depending on the number and depth of rhytides present. However,
since only the superficial fibers of the orbicularis oris should be treated,
then only 1–2 U of OnaBTX-A in 2 sites per ­quadrant, injected intra­
dermally, will suffice to produce the desired effect of diminishing the
perioral wrinkling while maintaining symmetrical movements and
proper function of the lips.20–22 In patients who have had treatments of
OnaBTX-A repeated over many years and, therefore, are well known to
the physician injector, slightly higher doses, but not more than 3 U of
OnaBTX-A at each injection site on occasion, can be placed into each lip
quadrant (Figures 15.14 and 15.15).
There was a report of some physicians using different patterns
to inject the lips with OnaBTX-A that include as many as 10 or 11
injection sites between the upper and lower lips, usually at the points
of maximal muscle contraction (Figure 15.16)23 However, this large
3
(a)
(b)
3
2
2
2
2
Figure 15.14  A 47-year-old patient at rest (a) before and (b) 2 weeks after her third OnaBTX-A treatment of perioral vertical rhytides. Note the subtle fullness of the ver­
milion and eversion of its border.
(a)
(b)
1
1
2
2
1
1
Figure 15.15  A 47-year-old patient at rest (a) before and (b) 2 weeks after her fourth OnaBTX-A treatment of perioral vertical rhytides. Note the subtle fullness of the ver­
milion and eversion of its border.
x
x
x
x
x
x
x
x
x
x
x
Figure 15.16  Illustrates previously suggested 11-point injection pattern to reduce
vertical lip wrinkles, which should only be utilized in extreme cases of exces­
sively deep rhytides. It usually is not advisable to inject any BoNT in the center
of the upper lip, because doing so might flatten the philtral trough. (See further
Reference Smychyshyn N, Sengelmann R. Botulinum toxin a treatment of perioral
rhytides. Dermatol Surg 2003; 29: 490–5.)

Botulinum Toxins in Clinical Aesthetic Practice
248
amount of OnaBTX-A and these many injection points are not
appropriate for most patients. In a dose ranging study where two
different fixed doses (7.5 and 12 units) of OnaBTX-A were used to
treat the upper and lower lips at the same time in 60 female subjects,
the patients receiving the higher dose (12 units) seemed to develop
adverse events more readily than those who received the lower dose
(7.5 units).24 This is the reason why it is imperative that the patient
returns 2–3 weeks after a treatment session with BoNT so that the
physician can evaluate the patient for any asymmetry or aberration
in lip function.21,22
For those patients who also have their lips injected with soft tis­
sue fillers, it has been found that injections of OnaBTX-A may pro­
long the effects of the fillers, since the constant muscle contraction
and stress on the filler material by normal, routine lip movement
is reduced by the effects of the OnaBTX-A.21,22,25 Generally, when
fillers are injected in the lips and other areas of the face during the
same session OnaBTX-A treatments are given, OnaBTX-A should
be injected first and before the fillers. This theoretically will allow
the targeted muscles to become saturated with the OnaBTX-A first
before having another product injected within the same area. If a
filler is injected first, however, some of the OnaBTX-A potentially
can be injected into the filler and not into the targeted muscle,
which can either dilute or disperse the OnaBTX-A and poten­
tially diminish its effect and impact on the final outcome of either
or both treatments. When other types of cosmetic procedures are
performed during the same treatment session in which OnaBTX-A
needs to be injected, for example, laser or other energy-based treat­
ments or even a surgical procedure, they should all be completed
before treating the patient with OnaBTX-A. The rationale for this is
that most of the time during these types of procedures the patient
is required to be mobile and either supine, prone, or in differ­
ent recumbent positions. These particularly peculiar movements
immediately following injections of OnaBTX-A potentially can be
detrimental to the efficacy of the OnaBTX-A treatment, and poten­
tially negatively affect the final results.
The total dose for OnaBTX-A injected into the upper lip should
not exceed 10 U,24 and that for the lower lip should never exceed
6 U, unless the physician knows the patient very well and has
treated the patient successfully without complications in the past
with high doses of OnaBTX-A (Figures 15.17 through 15.19).
(a)
(b)
1
2
1
1
2
2
Figure 15.17  A 56-year-old shown puckering (a) before and (b) 3 weeks after a treatment of OnaBTX-A of the perioral rhytides.
(a)
2
2
1
2
2
2
2
(b)
Figure 15.18  (a) A 59-year-old patient accentuating her dynamic perioral rhytides by puckering. She has had at least 4 OnaBTX-A treatments in the past. (b) Same patient
puckering 5 weeks after an OnaBTX-A treatment. Note the subtle fullness of the lips and the eversion of the vermilion border.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
249
Outcomes (Results) When Treating Perioral Lip Lines and
Rhytides (see Appendix 5)
Of all the areas of the face that are treated for wrinkling, the perioral
area is the least predictable and responsive no matter what invasive
or noninvasive modality is used, including injections of OnaBTX-A.
Even so, the perioral area is high on the treatment list when patients
request cosmetic rejuvenation of the face.
When OnaBTX-A injections of the lips are effective as intended, a
pleasing effacement of the depth of the vertical lip lines occurs, which
can dramatically improve the overall physical appearance and emo­
tional outlook of the patient. In addition to relaxing the superficial
fibers of the orbicularis oris and diminishing the wrinkles on the
cutaneous surface of the lip, there also can be a slight widening of
the philtrum and a noticeable eversion of the vermilion, producing
an attractive “pseudo” augmentation of the lips (Figures 15.14, 15.15,
and 15.18).20,21,23,24 Many feel that this pseudoaugmentation and ever­
sion of the lips are best produced when OnaBTX-A is injected directly
into the white roll of the vermilion border (Figure 15.11). However,
usually this technique can be very painful for the patient. Similar lip
fullness and eversion also can be realized when OnaBTX-A is injected
in a less painful way a few millimeters above and below the vermilion
border in the upper and lower lips, respectively, as described above
(Figure 15.12).20
Only dynamic perioral wrinkles can be attenuated by OnaBTX-A,
not the static rhytides that result from photodamage and age (Figure
15.4). For correction of static wrinkles and solar elastosis, various soft
tissue fillers, laser and energy-based treatments, and different resurfac­
ing procedures with adjunctive treatments of OnaBTX-A when appro­
priate will give the best results.21,25,26 Because only low doses should be
used to efface perioral rhytides, the usual duration of effect from injec­
tions of OnaBTX-A is sometimes just a little more than 2 and generally
no longer than 4 months.24
Complications (Adverse Sequelae) When Treating Perioral Lip
Lines and Rhytides (see Appendix 6)
The perioral area is probably the most difficult location on the face
to treat with injections of OnaBTX-A without frequent occurrence
of adverse sequelae. This is because, unlike the sphincteric action of
the orbicularis oculi, which has only one opposing levator muscle
(i.e., the frontalis) and a few co-depressor muscles (i.e., the corruga­
tor supercilii, procerus, orbicularis oculi, and depressor supercilii),
the orbicularis oris is interlaced with muscle fibers from the differ­
ent direct and indirect labial retractors and evertors of the upper
and lower lips, making it easy for injected OnaBTX-A to diffuse into
any one or a group of adjacent interdigitating levators or depressors.
Consequently, adverse sequelae or, annoying functional disturbances
are bound to occur.
Using a range of higher doses (≥8–10 U in the upper lip and
≥6–8 U in the lower lip) of OnaBTX-A will subject the patient to
difficulties with lip puckering when attempting to whistle or kiss
(Figure 15.19). A slightly asymmetric smile is relatively common in
the general population (see sections “Gummy Smile,” Chapter 14 and
“Asymmetric Smile of the Lower Lip,” Chapter 15). It also can be
iatrogenically created or accentuated by unequal dosing and asym­
metric placement of injections of OnaBTX-A in the lips. In the case
of overdosing, many different adverse functional changes can occur
which include but are not limited to the inability to form certain let­
ters (e.g., M, F, B, P, V, W, O, and U), to articulate different sounds,
and to pronounce certain words. Involuntary tongue, inner cheek,
and lip biting and even paresthesia of the lips may result, along with
flattening of the philtrum. There can be a disturbance in propriocep­
tion of the lips, which makes it difficult to apply lipstick, whistle,
kiss, or brush the teeth. There also can be a concomitant inability to
approximate the lips tightly enough to prevent air, fluid, or even food
incontinence. Incontinence of fluid causes one to drool or actively
dribble liquid out of the mouth while drinking from a glass or cup,
or sipping from a straw, or eating from a spoon.24,27–29 Incontinence
of solids and food can be even more embarrassing, depending on
one’s social setting when it occurs. The inability to purse or pucker
the lips can last beyond 2–4 weeks after a treatment of OnaBTX-A.
Consequently, OnaBTX-A treatments of the lips should never be
offered to certain types of people, for example, musicians and instru­
mentalists, or those who sing on a regular basis (e.g., in a choir at
church or on stage) or professional vocalists. Other individuals who
should avoid OnaBTX-A treatments of their lips are scuba divers and
snorkelers; public speakers, especially television and radio announc­
ers; and dog sitters and animal trainers who need to whistle and
make subtle vocal sounds to enforce a learned response.
In the Cohen et  al. dose ranging study, most of the untoward
sequelae seemed to be dose-dependent, which included weakness
and numbness of the lips, trouble eating and an inability to kiss,
lip dryness, lip fullness, lip swelling, and decreased mobility of the
lips and mouth. A few of those lip movement and functional dif­
ficulties (dryness of the lips, influenza-like syndrome, bruising of
the left upper lip, and decreased mobility of the mouth) continued
for more than 20 weeks beyond the termination of the study in 15%
(a)
(b)
Figure 15.19  A 68-year-old patient is seen puckering (a) before and (b) 3 weeks after a treatment of OnaBTX-A. The patient experienced some difficulty puckering following
the injections.

Botulinum Toxins in Clinical Aesthetic Practice
250
of those patients who were treated with the higher 12-unit dose of
OnaBTX-A.27
Therefore, one should not be tempted to inject progressively
higher doses of OnaBTX-A into the lips similar to the way one can
increase the dose injected in the periorbital area. Doing so will
definitely lead to any number of the  adverse sequelae as identi­
fied above. It is important to understand that there is only a very
narrow margin for the successful treatment of the orbicularis oris
with OnaBTX-A. If 2 U of OnaBTX-A per quadrant is injected
into a patient’s lips effectively and without untoward sequelae,
then as little as an additional 1 or 2 U of OnaBTX-A in the upper
or lower lip in that same individual may result in some or all of
the adverse side effects previously detailed. Those most intoler­
able adverse effects are an asymmetric smile and lack of sphincter
control, causing food and liquid incontinence, and difficulty with
sound production and speech articulation. So, the temptation to
inject even 1 U more in an upper or a lower lip to improve the
results or extend the duration of an OnaBTX-A treatment must
be overcome, unless visible ineffectiveness of a particular dose of
a previous OnaBTX-A treatment already has been experienced
by the patient. Then either additional units at the 2- to 3-week
follow-up visit can be given, or a gradual increase in dose (by no
more than 1 U of OnaBTX-A) and number of injection sites (one
site at a time) can be attempted with each subsequent OnaBTX-A
treatment session (Figure 15.20). When OnaBTX-A is ineffectively
injected, or there is some loss of product while injecting, prevent­
ing a full complement of OnaBTX-A to reach the targeted muscle
fibers, then an uneven outcome can result (Figure 15.20). Avoid
injecting OnaBTX-A too close to the corners of the mouth. This
can result in incompetent commissures, eclabion, an asymmet­
ric smile, aberration in speech, drooling and dribbling, and even
incontinence of solid food.
Of all the areas on the face to inject OnaBTX-A, the lips are the
most painful. The more superficial (i.e., intradermal) the injection,
the more painful it will be. Icing and the prolonged application of a
topical anesthetic with occlusion may alleviate some of the pain that
accompanies such superficial injections in the lips. Forewarning the
patient of the potential side effects and the particular painfulness of
the treatment does not seem to dissuade those who are determined
to rid themselves of these unsightly lipstick-trailing rhytides. In con­
tradistinction, superficial injections in the perioral area do not elicit
ecchymoses with the same ease and frequency that superficial injec­
tions in the periorbital area do.
Figures 15.21 through 15.26 are additional examples of different
patients treated with OnaBTX-A for perioral rhytides.
Treatment Implications When Injecting Perioral Lip Lines
and Rhytides

1. Only dynamic wrinkles in the lips are reducible by OnaBTX-A
treatments. A thorough and accurate assessment of the patient
is the key to a successful outcome.

2. Treating hyperkinetic superficial fibers of the orbicularis oris
with OnaBTX-A will relax surface rhytides, evert the vermil­
ion, and create the appearance of fullness in the lips.

3. Inject low doses of high-volume OnaBTX-A intradermally in
the lips, and see the patient 2–3 weeks after each treatment.
It is absolutely imperative to employ a meticulous intrader­
mal injection technique when injecting lips with OnaBTX-A,
because the frequency, intensity, and duration of adverse
sequelae is technique dependent.

4. Treat the lips with symmetrically placed injections of OnaBTX-A
in all four quadrants of the pars peripheralis. Each individual
injection site can be dosed differently with the tip of the needle
advanced to just beneath the vermilion border.

5. Inject the lower lip conservatively and with a slightly lower dose
of OnaBTX-A than the upper lip to avoid aberrations of normal
labial function. Injecting OnaBTX-A into the base of the phil­
trum may flatten its contour.

6. Avoid injecting OnaBTX-A close to the corners of the mouth
for risk of creating incompetent commissures, eclabion, an
asymmetric smile, drooling, and even dribbling.

7. The pretreatment application of ice or a topical anaesthetic with
occlusion may reduce the particular pain experienced when
lips are injected.
ASYMMETRIC SMILE OF THE LOWER LIP
Introduction: Problem Assessment and Patient Selection
Many men and women are naturally born with an asymmetric
smile (see Asymmetries, p. 127; Gummy smile, p. 220 and Figures
15.27 through 15.29). This also can be a manifestation of a family
trait (Figure 15.30). For many who display this type of smile this is
a source of considerable embarrassment, especially when they are in
(a)
(b)
Figure 15.20  A 43-year-old patient puckering (a) before and (b) 3 weeks after her first OnaBTX-A treatment for perioral vertical rhytides. Note the persistence of wrinkles
in the right upper quadrant (arrow) due to inadequate treatment on that side.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
251
(a)
(b)
(c)
(d)
1
2
1
1
1
1
1
2
1
2
1
1
1
1
1
2
Figure 15.21  (a) A 53-year-old patient with deep perioral rhytides and severe solar elastosis of the face and lips at rest before and (b) 2 weeks after treatment with OnaBTX-A.
Note the subtle fullness of the lips and the eversion of the vermilion border. (c) Same patient puckering before and (d) 2 weeks after treatment with OnaBTX-A. Many of the
persistent wrinkles are of the static type, caused by photoaging. Note the subtle fullness of the lips and the eversion of the vermilion border.
(a)
(b)
1
1
1
1
1
1
1
1
Figure 15.22  A 66-year-old patient is shown at rest with perioral rhytides (a) before and (b) 1 month after a treatment with OnaBTX-A in the upper and lower lips and a
hyaluronic acid filler in the marionette lines, prementum, and prejowl areas.

Botulinum Toxins in Clinical Aesthetic Practice
252
(a)
(b)
(c)
(d)
1
2
2
1
1
1
1
1
1
1
1
1
1
1
2
2
Figure 15.23  (a) A 68-year-old patient is shown at rest with perioral rhytides before and (b) 2 weeks after a treatment with OnaBTX-A. Note the subtle fullness of the lips
and the eversion of the vermilion border. (c) Same patient puckering before and (d) 2 weeks after treatment with OnaBTX-A.
(a)
1
2
2
2
2
1
(b)
Figure 15.24  A 57-year-old patient is shown at rest with perioral rhytides (a) before and (b) 2 months after a treatment with OnaBTX-A of the upper and lower lips and a
hyaluronic acid filler in the marionette lines, prementum, and prejowl areas.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
253
2
(a)
(b)
2
2
2
Figure 15.25  A 44-year-old patient is shown at rest with perioral rhytides (a) before and (b) 2 weeks after a treatment with OnaBTX-A. Note the subtle fullness of the lips
and the eversion of the vermilion border.
1
(a)
(b)
2
1
2
2
2
Figure 15.26  A 47-year-old patient is shown puckering with perioral rhytides (a) before and (b) 3 weeks after a treatment with OnaBTX-A. The mentalis and platysma were
not treated; note the dimpling of the mentum and the perimental furrows.
Figure 15.27  In this 55-year-old female, an asymmetric smile is caused by hyperki­
netic lateral levators of the left upper pars peripheralis of the lips.
Figure 15.28  In this 62-year-old male, an asymmetric smile is caused by hyperki­
netic central levators of the right upper pars peripheralis of the lips.

Botulinum Toxins in Clinical Aesthetic Practice
254
a socially interactive situation. Just like those with a gummy smile
(see pp. 220–230) they are reticent to freely grin in public, and seek
different ways to conceal the gape of their mouths in the presence of
others when laughing or smiling. Those who have a prominent posi­
tion in society or in the workplace are especially self-conscious of
their obviously “crooked smile.” Many prefer not to smile when being
photographed, and will avoid family and social events where photo­
graphs are being taken.
Functional Anatomy of a Lower Lip Asymmetric Smile
(see Appendix 2)
No matter what type of smile one has (zygomatic, canine, or full
denture), if it is asymmetrical or “crooked” it is always a source
of anxiety and self-consciousness for the bearer, whether male or
female30–33 (see Figure 15.70 for types of smiles). Asymmetric smiles
can occur because of segmentally weakened or hyperfunctioning
muscles on either side of the upper or lower lips. If the asymmetry
appears in the upper lip, one or more of the many upper lip leva­
tors or a segmental portion of the orbicularis oris may be involved
unilaterally or bilaterally (see “Gummy Smile” earlier in this chap­
ter). If the asymmetry appears in the lower lip, it is usually caused
by a unilateral malfunctioning of a lower lip depressor that is usu­
ally weaker or stronger than its contralateral paired muscle with or
without the segmental involvement of the orbicularis oris. Lower
lip asymmetries are more easily corrected because unlike the intri­
cate network of the upper lip levators, the problem commonly stems
from a hyperkinetic depressor labii inferioris or occasionally a
depressor anguli oris and rarely both.33 Isolated quadrants or por­
tions of the muscle fibers of the lower orbicularis oris theoretically
also can be involved.
The depressor labii inferioris is a quadrilateral muscle that origi­
nates inferior to the mental foramen at the oblique line of the lower
lateral surface of the body of the mandible between the symphysis
menti and the mental foramen. As one of the direct labial retractors,
its fibers travel upward and medially overlying the mental foramen to
insert directly into the skin and mucosa of the lower lip, decussating
with fibers of its paired muscle from the contralateral side along with
some muscle fibers of the lower orbicularis oris. Inferiorly and later­
ally, it is continuous with the platysma (pars labialis) (Figure 15.31).
At its origin, the depressor labii inferioris is approximately 3 cm wide,
and superimposed laterally by muscle fibers of the depressor anguli
oris for about 1–2 cm. It then narrows to approximately 2 cm wide
before it inserts into the superior aspect of the lower lip.
(a)
(b)
Figure 15.30  (a) A father (55 years old) and (b) his daughter (20 years old) demon­
strate the same type of idiosyncratic, asymmetric smile caused by a hyperkinetic
right depressor labii inferioris. The daughter also has an asymmetric smile of the
right upper pars peripheralis with deep nasolabial grooves and folds.
2
1
3
Figure 15.31  Depressor labii inferioris is a square, deeply situated muscle on the
chin and it depresses the lateral aspect of the lower lip downward while gently evert­
ing the vermilion. It is one of the direct labial retractors inserting directly into the
skin and mucosa while other fibers interdigitate with some of the lower fibers of the
orbicularis oris and platysma (pars labialis). 1, depressor labii inferioris; 2, depres­
sor anguli oris; 3, platysma–pars labialis passed underneath depressor anguli oris.
Figure 15.29  In this 61-year-old female, an asymmetric smile is caused by a hyper­
kinetic depressor labii inferioris in the right lower pars peripheralis.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
255
The function of the depressor labii inferioris is to pull the lower lip
downward and laterally slightly everting the vermilion when a person
is chewing, drinking, smiling, laughing, or speaking. Otherwise, one
would bite or chew their lower lip while performing these functions.
It should contract symmetrically and in unison with its paired coun­
terpart on the opposite side of the chin. This is not always the case in
some individuals. The depressor labii inferioris is one of the muscles
used when expressing sorrow, irony, melancholy, and doubt.
Dilution When Treating a Lower Lip Asymmetric Smile
(see Appendix 3)
Because of the extensive interlacing of muscle fibers in the perioral area,
the success of treating a particular muscle in the lower face is predi­
cated on not having OnaBTX-A diffuse beyond the area of injection
and the targeted muscle. Consequently, minimal amounts of low-vol­
ume, highly concentrated OnaBTX-A should be used when injecting a
perioral muscle. Therefore, experienced physicians will reconstitute a
100 U vial of OnaBTX-A with only 1 mL of normal saline.
Dosing: How to Correct the Problem (see Appendix 4) (What to Do
and What Not to Do) When Treating a Lower Lip Asymmetric Smile
Ordinarily, a unilateral hyperkinetic muscle of the face, whether idio­
syncratic or secondarily induced, can be weakened with injections of
OnaBTX-A to correct an asymmetry (Figure 15.32). Depending on
the type, location, and strength of the muscles creating the asymme­
try, it is advisable for the physician injector to identify the offending
muscle correctly and determine the dose of OnaBTX-A necessary
for the correction of the asymmetry at the time of treatment. Each
patient’s problem should be evaluated individually and a suitable
solution deduced from the presenting asymmetry of the patient’s
idiosyncratic anatomy. When treating muscles in the lower face,
very low doses of OnaBTX-A are all that are necessary to produce a
desired, long-lasting effect. Dramatic results can be obtained usually
with less than 4 or 5 U of OnaBTX-A.
Prior to injection the patient should be in the sitting or semi­
reclined position while forcibly contracting the muscle(s) to be
treated. Commonly it is the depressor labii inferioris that is hyper­
kinetic and  creating an asymmetric smile. As the patient smiles
energetically, the location of the hyperkinetic muscle is easily visu­
alized (Figure 15.32a,c). The needle should pass perpendicular to
the skin’s surface and enter directly into the thickest part of the
muscle belly. This injection point should be inferior to the mental
crease which are the lower limits of the orbicularis oris. Generally,
2–4 U of OnaBTX-A will weaken the hyperfunctional depressor
labii inferioris sufficiently enough to realign an asymmetric smile
(Figures 15.32 and 15.33).33,34 Slow, deliberate injections will prevent
pain and distant spread of OnaBTX-A, averting adverse sequelae.
Outcomes (Results) When Treating a Lower Lip Asymmetric
Smile (see Appendix 4)
When the problem has been correctly assessed, and the proper
conservative dose of OnaBTX-A determined, weakening the hyper­
kinetic muscle on the side of the face producing the asymmetry
with injections of OnaBTX-A will correct the asymmetry (Figures
15.32 and 15.33). The effect of a single treatment can last beyond
5–6 months.33 It is best to treat an asymmetry with a lower dose
of OnaBTX-A which can be increased by a touch-up treatment
2–3 weeks later when the patient returns for his or her obligatory
post-treatment evaluation. Correcting a problem conservatively,
albeit possibly insufficiently, allows both the patient and the physi­
cian to assess clearly the appropriateness of the corrective action.34
Subsequently, additional units of OnaBTX-A can then be injected
with confidence to adequately treat the problem to the satisfaction
of patient and physician. In the lower face, the muscles are small,
intermingled with indistinct borders, and do not always function
in the same way in every patient.35 The shape and contour of the
mouth and whether it is symmetrical or asymmetrical will depend
on how the perioral muscles function in a particular individual.
When there is an obvious asymmetry, 1 or 2 U of OnaBTX-A can go
a long way in modifying how perioral muscles contract and interact
with each other.
In a study by Benedetto,33 four females and one male were treated
for lower lip asymmetry. Four were caused by a hyperkinetic right
depressor labii inferioris, one by a left one. Four of the patients were
aware of their asymmetry which was present since birth or early child­
hood. One was not aware of having an asymmetric smile. OnaBTX-A
was used to correct the asymmetric smile of all the patients, with only
1–3 units. The smiles became level and symmetrical within one week
of the treatments, which lasted anywhere from 6 to 7.5 months with
the first treatment session and even longer with subsequent treat­
ments, even when a lower dose was used. Such simple outpatient
myorelaxation of the depressor labii inferioris when indicated for the
properly selected patients has made invasive surgical resectioning of
the depressor labii inferioris, a procedure of the past, unwarranted
and virtually unnecessary.34
Complications (Adverse Sequelae) When Treating a Lower Lip
Asymmetric Smile (see Appendix 6)
An erroneous assessment and fallacious conclusion to a problem in
the lower face can produce incomplete and even untoward results,
which can become an intolerable annoyance and even a functional
problem to the patient. Therefore, a thorough knowledge of the anat­
omy and function of the muscles of the face in the particular area
to be treated is absolutely necessary when one is attempting to treat
a patient with OnaBTX-A. This is especially important when the
problem is not a recognized, commonly occurring complaint with
well-established and approved techniques of treatment as it is with
glabellar and lateral canthal frown lines. Idiosyncratic or iatrogenic
asymmetries need to be corrected on a case-by-case basis and expert
understanding of functional anatomy is paramount. Overzealous
treatment, especially in the lower face, of any problem can only lead to
inadvertent adverse sequelae. In the case of an asymmetric smile, one
or two extra units of OnaBTX-A can create the same complications
of an adynamic smile and incompetent buccal sphincter, causing dif­
ficulty with eating, drinking, swallowing, and speech articulation.
Figures 15.34 through 15.36 are additional examples of different
patients treated with OnaBTX-A for an asymmetric smile.
Treatment Implications when Injecting an Asymmetric Smile

1. Know the functional anatomy of the muscles to be treated.

2. Inject low-volume, minimal doses of OnaBTX-A directly into
the belly of the hyperkinetic muscles in question.

3. First treatments should be conservative with low doses of OnaBTX-A
to confirm the appropriateness of the treatment.

4. All first-time and subsequently treated patients must be re-
evaluated 2–3 weeks after an OnaBTX-A treatment to assess
their results and to monitor the patients’ satisfaction with the
outcome.

5. Assess and treat every patient individually. No two patients
or their individual problems are alike and therefore cannot be
treated in the same manner.

6. Reevaluate each patient’s problem before every treatment because
the dosage of subsequent injections may change depending on
how the treated muscles respond and reanimate over time.

7. Treatment results are long lasting, and their duration can
remain even longer with each subsequent treatment.

Botulinum Toxins in Clinical Aesthetic Practice
256
3
(a)
(b)
(c)
(d)
(e)
(f)
1
1
Figure 15.32  A 47-year-old female with an idiosyncratic asymmetric smile (a) before and (b) 3 weeks after 3 U of OnaBTX-A were injected into her left depressor labii inferi­
oris. (c) Same patient seen 3 months after the first treatment of her left depressor labii inferioris. An additional 1 U of OnaBTX-A was injected at this time. (d) Same patient
seen again 4 months after her second touch-up treatment. (e) Same patient seen with lasting results 8 months after her second treatment. An additional 1 U of OnaBTX-A
was injected to maintain these results. (f) Patient seen again 7 months after her third treatment.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
257
2
(a)
(b)
Figure 15.33  A 22-year-old female with an idiosyncratic asymmetric smile (a) before and (b) 4 months after 2 U of OnaBTX-A were injected into her right depressor labii
inferioris for the second time. Note the absence of dental show of the lower teeth.
2
(a)
(b)
Figure 15.34  A 55-year-old patient with an idiosyncratic asymmetric smile (a) before and (b) 3 weeks after 2 U of OnaBTX-A were injected into her right depressor labii
inferioris. Note the eversion of the vermilion border.
1
(a)
(b)
Figure 15.35  A 61-year-old patent with an idiosyncratic asymmetric smile (a) before and (b) 5 months after 1 U of OnaBTX-A was injected into her right depressor labii
inferioris.

Botulinum Toxins in Clinical Aesthetic Practice
258
MELOMENTAL FOLDS
Introduction
Patients whose corners of the mouth chronically project downward
commonly also will possess pronounced melomental folds. These
superfluous folds of skin are created by deep furrows emanating
away and downward from the oral commissures. They also are iden­
tified as a labiomandibular crease, “drool grooves,” or “marionette
lines.” Their diverse appearance varies according to a person’s indi­
vidual muscular variations and the thickness of the subcutaneous
fat.36 Usually becoming more obvious in the fifth decade of life,
melomental folds seem to appear more readily in smokers and when
smiling or opening the mouth laterally. These telltale signs of aging
involuntarily impart to others the negative expressions of sadness,
tiredness, disapproval, unpleasantness, and melancholia, and even
an angry demeanor, emphasizing negative impressions produced by
an inverted smile.35,36 When these “marionette lines” extend down­
ward along the lateral sides of the mentum they reinforce the down­
ward turn of the corners of the mouth creating an inverted smile or
“Chinese moustache” and evoke the outward appearance of someone
who is old and senile, no matter how young they might be chrono­
logically (Figure 15.37). Marionette lines can be a source of frustra­
tion and embarrassment during daily social interactions, or for those
who maintain a prominent position in the workplace. Until recently,
the only way to efface these lines was either by invasive surgical pro­
cedures such as rhytidectomies, threading, lifting, subcision, and
skin resurfacing, or injections of soft tissue fillers which can produce
results that are remedial but temporary. Injections of OnaBTX-A can
be given to supplement these procedures enhancing and even pro­
longing their results, bringing the treatments of melomental folds a
little closer to a more satisfactory outcome.37–39
Functional Anatomy of Melomental Folds (see Appendix 2)
Formation of an inverted smile because of the downward projection
of the corners of the mouth is produced by the hyperkinetic activity
of the depressor anguli oris pulling down on the oral commissures
(Figure 15.38).40–42 The depressor anguli oris is a variably sized trian­
gular muscle (also known as the triangularis) whose wide base origi­
nates on bone at the mental tubercle and along the external oblique
2
(a)
(b)
Figure 15.36  A patient with an idiosyncratic asymmetric smile (a) before and (b) 2 months after 2 U of OnaBTX-A were injected into her left depressor labii inferioris.
(a)
(b)
Figure 15.37  (a) This 52-year-old female at rest has marionette lines that extend down the lateral sides of the mentum creating an inverted smile because of a hyperkinetic
depressor anguli oris. (b) This 37-year-old female grimacing displays a deep, inverted smile, also because of a hyperkinetic depressor anguli oris. Note the asymmetry in
the depth and length of the marionette lines in both patients.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
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(a)
(b)
(c)
(e)
(f)
(d)
2
1
4
5
6
3
Figure 15.38  (a) Depressor anguli oris inserts into the modiolus before interdigitating with the risorius, platysma (pars labialis), levator anguli oris, and the orbicularis
oris. It pulls the corners of the mouth downward. 1, orbicularis oris; 2, levator anguli oris; 3, modiolus; 4, depressor anguli oris; 5, platysma (pars labialis); 6, platysma
(pars mandibularis). (b) An inverted smile with early formation of marionette lines. A hyperkinetic depressor anguli oris pulls the lateral oral commissures of the mouth
downward, resulting in (c, d) early and (e, f) advanced melomental folds or “marionette” lines.

Botulinum Toxins in Clinical Aesthetic Practice
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line of the body of the mandible below the canine premolar and first
molar, lateral and superficial to the bony origin of the larger depressor
labii inferioris, which it partially overlaps40 (Figure 15.10). The muscle
fibers of the depressor anguli oris narrow as they travel upward and
converge onto the angle of the mouth, where some muscle fibers insert
directly into the undersurface of the dermis while other fibers insert
into the modiolus and then interdigitate with muscle fibers of the orbi­
cularis oris, risorius, and levator anguli oris near the upper lip and
the zygomaticus major and buccinator and platysma modiolaris at the
oral commissures18 (Figure 15.38). Its overall size can vary according
to the shape of an individual’s facial bony structure.5 In addition, the
lower posterior fibers of the depressor anguli oris interdigitate with
those muscle fibers of the upper platysma (pars labialis) and cervi­
cal fascia that converge toward the lateral oral commissures. In some
individuals, the depressor anguli oris will traverse the midline inferior
to the mental tubercle and decussate with fibers of its paired muscle of
the opposite side, creating the transversus menti or the “mental sling.”4
Hur et al. investigated the topographical relationship of the depres­
sor anguli oris to the mental foramen.36 Although the position of the
mental foramen can vary from individual to individual, depending
on their idiosyncratic bone structure, it is generally found below the
mandibular second premolar region. They also observed that most
commonly the mental foramen was located under the middle third of
the depressor anguli oris between the cheilion and the inferior border
of the mandibule. In addition, the most common course of the buccal
and marginal mandibular branches of the facial nerve was under the
middle and lower thirds of the lateral border of the depressor anguli
oris. In all cadaver specimens studied, the motor end plates were
abundantly located in the lower portion of the depressor anguli oris
inferior to the mental foramen, which they therefore concluded was
the most effective site for injecting OnaBTX-A.36
The function of the depressor anguli oris is to depress the oral com­
missures slightly laterally and downward when opening the mouth. The
depressor anguli oris is an antagonist to the levator anguli oris, risorius,
and zygomaticus major, displacing the corners of the mouth downward
and slightly laterally when it contracts in an expression of grief, sorrow,
and sadness. The melomental sulcus, or marionette line, generally is
located in the center and over the upper aspect of the depressor anguli
oris5,40 (Figure 15.38e, f). While in certain patients, the inferior aspect
of the marionette line contributes to the formation of the prejowl or
labiomandibular sulcus, fixed in place by the mandibular (retaining)
ligament. Posterior to the depressor anguli oris and anterior to the
jowl, the mandibular ligament adheres the dermis to the mandible.5 On
opening the mouth, the labiomental sulcus (mental crease) across the
chin becomes more horizontal and deeper in its center.4
Dilution When Treating Melomental Folds (see Appendix 3)
When treating the depressor anguli oris and the perioral area,
OnaBTX-A should not be allowed to diffuse beyond the targeted
muscle fibers; otherwise, cosmetic aberrations such as an asymmetric
smile, and functional disturbances such as drooling, dribbling, and
even dysarthria are likely to follow. Therefore, the highest volume of
diluent that should be used to reconstitute a 100 U vial of OnaBTX-A
is 1 mL of normal saline. Any volume of diluent higher than 1 mL is
sure to invite adverse sequelae.
Dosing: How to Correct Problem (see Appendix 4) (What to Do
and What Not to Do) When Treating Melomental Folds
The downward angling of the “marionette lines” can be improved by
injecting 3–6 U of OnaBTX-A intramuscularly in the center of the body
of the mandible at a point that is most inferior to an imaginary verti­
cal line that passes through the nasolabial sulcus (Figure 15.39b). This
point should be approximately 8–10 mm lateral to the oral commissure
and 8–15 mm inferior to this point, depending on the idiosyncratic
shape of the patient’s face and anterior projection of the mandible.
The appropriate injection point can be identified by palpating some­
one who is actively contracting the corners of the mouth downward
(Figure 15.39c) while pronouncing the letter “E” in an exaggerated
fashion (Figure 15.39d).29,41 Having the patient smile intensely with the
lower lip clenched upward and against the upper lip (i.e. a closed mouth
smile) and then again enunciating the letter “E” also will help identify
a hypertrophic depressor anguli oris. Another maneuver to assist in
localizing the depressor anguli oris is to have the patient bite down,
forcibly contracting the jaw muscles. This will contract and enlarge the
belly of the masseter, which is a muscle very easily identified by palpa­
tion (Figure 15.40). In most individuals, the depressor anguli oris lies
approximately 1 or 2 mm to 1 cm anterior to the masseter depending
on the shape and projection of the jaw and mandible. After the patient
clenches his or her teeth and the anterior border of the masseter is iden­
tified, have the patient exaggerate the pronunciation of the letter “E.”
The location of a hypertrophic depressor anguli oris should be easily
palpated along the anterior border of the masseter and along the body
of the mandible. At times, the depressor anguli oris can be detected
more easily by palpating it intraorally along the inferior alveololabial
sulcus as the patient actively contracts it (personal communication
from Luitgard Wiest, MD). Yet another way to identify the appropriate
injection point of the depressor anguli oris is to have the patient forc­
ibly contract his or her platysma. Those patients who possess platys­
mal neck bands frequently will form a lateral neck band that is directly
beneath the point where fibers of the platysma mandibularis and the
depressor anguli oris decussate. Just cephalad to this lateral platysmal
neck band on the superior aspect of the body of the mandible is the
general vicinity where OnaBTX-A should be injected (Figure 15.39e,f).
Place the patient in the upright sitting or semireclined position.
At the point where the contracted and thickened belly of the depres­
sor anguli oris can be felt, insert the needle perpendicular to the skin
surface over the body of the mandible about 3–5 mm above the infe­
rior edge of the mandible. Advance the needle 3–4 mm deep into the
skin until it passes through the subcutaneous tissue and barely into
the muscle (approximately mid-depth) just superior to the bony origin
of the muscle. Inject slowly 4–6 U of OnaBTX-A. Remember, a sub­
stantial amount of the lower medial aspect of the depressor anguli oris
overlies the depressor labii inferioris (Figure 15.40a), so advancing the
needle too deeply and anteriorly may unavoidably expose some of the
posterior fibers of the depressor labii inferioris and possibly orbicularis
oris to the injected OnaBTX-A. Also, if OnaBTX-A is injected too high
and laterally from the depressor anguli oris, the zygomaticus major,
risorius, and platysma can be affected.18
However, some authors prefer to inject lower dosages of only 2 units
of OnaBTX-A into the depressor anguli oris at three separate loca­
tions.1,5,40 The lower two injection points (I and II in Figure 15.40b) are
applied deeply into the muscle until bone is contacted about 3–5 mm
above the mandibular border in the same general vicinity of the mus­
cle’s lower bony origin, but much more deeply than what was discussed
above. So, instead of one injection of 4–6 units of OnaBTX-A (Figure
15.39a), this technique recommends placing two injections of only 2
units of OnaBTX-A about 2–3 mm apart from each other, just anterior
to the mandibular retaining ligament. Caution should be given not to
inject OnaBTX-A too anteriorly toward the chin with this technique.
Otherwise, the depressor labii inferioris will be unintentionally affected
by these injections, producing speech difficulties and lip asymmetry at
rest and in motion. The third injection point (III in Fig, 15.40b), when
given, must be applied superficially in the midline of the upper aspect of
the muscle before it inserts into the oral commissure, and always behind
the marionette line, approximately 0.5 mm below and lateral to the com­
missure. A wheal should be elicited with this injection, otherwise the

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
261
(a)
(c)
(d)
(e)
(f)
2
X
1
(b)
Figure 15.39  (a) The correct point of injection for the depressor anguli oris is not the anterior one that is directly inferior to the downward extension of the melomental
crease (marking on the right), but slightly more posteriorly (marking on the left, arrow) at the most inferior point of an imaginary line that passes through the nasolabial
sulcus; red arrows represent directional vectors of how to determine where to inject. (b) Placing the injection point too anteriorly (black X) injects the depressor labii
inferioris. (1) The proper injection point is at the continuation of the nasolabial fold which extends to the mandibular border (dotted red line). This point is directly over
the depressor anguli oris (2 and yellow dot). (c) The injection point can be identified by feeling the contraction of the depressor anguli oris as the patient actively contracts
the corners of the mouth downward; (d) and pronounces the letter “E” in an exaggerated manner. (e) Note the lateral platysmal band, which points to where the depres­
sor anguli oris can be injected with OnaBTX-A. (f) Injecting the depressor anguli oris at the most inferior point of the nasolabial sulcus in the center of the body of the
mandible is approximately 1 cm lateral and 1 cm inferior to the corner of the mouth. Note how this usually corresponds to the uppermost aspect of the platysmal band.

Botulinum Toxins in Clinical Aesthetic Practice
262
injection will be given too deeply and the orbicularis oris will surely be
affected, creating buccal incompetence and drooling at the very least.40
This third, upper, superficial injection point to treat the depressor anguli
oris has never been attempted by this author for fear of creating unnec­
essary untoward sequelae. Only one deep injection point with at least 4
units of low volume, concentrated OnaBTX-A at the mandibular border
is the preferred technique and has always resulted in sufficient, natu­
rally appearing results to satisfy patients without creating any additional
adverse perioral functional changes.
In Asian patients, because of differences in the location of their
modioli, from Caucasians and Africans, Choi et  al. recommend
injecting OnaBTX-A into a point that is less than 45 degrees lateral
and less than 30 degrees medial to an imaginary vertical line that
passes through the center of a palpable modiolus, which in reality
is clinically similar in location to the injection technique described
above for non-Asian patients.18
If the depressor anguli oris cannot be unequivocally identified
and palpated, then it should not be treated. Inject precise amounts
of OnaBTX-A accurately into the depressor anguli oris, since the
orbicularis oris and depressor labii inferioris are immediately adja­
cent to it, and unsightly and dysfunctional perioral changes will be
avoided. Otherwise, if either one of these two muscles are inadver­
tently weakened along with the depressor anguli oris, unintentional
side effects will result. Care also should be taken not to inject into
the marginal mandibular nerve and facial artery and vein that lie in
this general vicinity in a bony groove just anterior to the masseter
and posterior to the mandibular retention ligament. If the depressor
anguli oris is palpated over this bony groove, lift the skin and muscle
with the nondominant hand before injecting OnaBTX-A. With this
technique, OnaBTX-A can be injected directly into the fibers of the
depressor anguli oris, while avoiding injecting the neurovascular
structures beneath the muscle in that area.43 Since the depressor
anguli oris is wider at its origin along the body of the mandible, it is
advisable to inject it in this location and not near its insertion close
to the corners of the mouth where it narrows and interdigitates with
other perioral muscles (Figure 15.38). In fact, when there is an obvi­
ous platysmal band just inferior to where the depressor anguli oris
is injected, an additional 2–3 U of OnaBTX-A also can be injected
into the apex of that platysmal band approximately 2–3 cm inferior
to the lower margin of the body of the mandible. This will ensure a
complete relaxation of the depressor anguli oris and an uplifting of
the oral commissures.
Outcomes (Results) When Treating Melomental Folds
(see Appendix 5)
Injections of OnaBTX-A will relax the depressor anguli oris and per­
mit the unopposed elevation of the corners of the mouth to occur by
the upward pull of the levator anguli oris, the zygomaticus major,
and risorius. When the corners of the mouth are relaxed and ele­
vated by injections of OnaBTX-A, a person appears younger and nat­
urally relaxed and pleasant (Figures 15.41 and 15.42a, b). Depending
on the extent and depth of the marionette lines present, this area is
best treated in combination with soft tissue fillers and some form
of laser or energy-based treatments whether ablative or nonablative.
OnaBTX-A then will usually prolong the beneficial effects of such
rejuvenation procedures. The beneficial effects from injections of
OnaBTX-A can last from 3 to 4 months and possibly even longer.37
Complications When Treating Melomental Folds (Adverse
Sequelae) (see Appendix 6)
It is extremely important to exercise caution when injecting the depres­
sor anguli oris too close to the mouth, since injections that are too
medial can cause an ipsilateral weakness of the depressor labii inferi­
oris, resulting in a flattening of the lower lip contour when the mouth
attempts to form an “O,” “U,” or “W,” in addition to an asymmetric
smile (Figure 15.42d). Additional adverse sequelae when the depressor
labii inferioris is inadvertantly weakened include the inability to purse
or pucker the lips symmetrically, seal the lips to contain solid food or
fluid in the mouth or to drink from a glass, sip from a straw, or eat
from a spoon (Figure 15.19b). To perform these maneuvers, a person
(a)
(b)
2
4
a
b
1
5
3
II
III
I
Figure 15.40  (a) The masseter can be easily palpated when patients clench their teeth. Note the position of the depressor anguli oris on the left. It normally is found later­
ally and superficially to the depressor labii inferioris and anteriorly to the masseter. 1, masseter; 2, depressor anguli oris; 3, depressor labii inferioris; 4a, platysma, pars
mandibularis; 4b, modiolus; 5, mandibular retaining ligament (dotted black line). (b) This technique recommends placing two injections of only 2 units of OnaBTX-A
about 2–3 mm apart from each other just anterior to the mandibular retaining ligament. These injection points, I and II, are applied deeply into the muscle until bone is
contacted about 3–5 mm above the mandibular border in the same general vicinity of the muscle’s lower bony origin. The third injection point, III, when given, must be
applied superficially in the midline of the upper aspect of the muscle before it inserts into the oral commissure, and always behind the marionette line, approximately
0.5 mm below and lateral to the commissure.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
263
(a)
4
4
(b)
Figure 15.41  (a) This 47-year-old patient possesses a deep labiomental furrow and downward projecting corners of the mouth (a) before and (b) four months after a second
treatment of 4 U of OnaBTX-A was injected into the depressor anguli oris bilaterally. Note the uplifted corners of the mouth and the patient’s more pleasant appearance
after a treatment of OnaBTX-A.
(a)
(b)
(c)
(d)
4
4
4
4
Figure 15.42  A 52-year-old patient (a) at rest and (b) 3 weeks after 4 U of OnaBTX-A were injected into each depressor anguli oris. (c) Same patient frowning before and
(d) 3 weeks after that same treatment. Note the slightly asymmetric smile with forced frowning in (d), which lasted approximately 2-3 weeks after the initial OnaBTX-A
treatment, and were of no concern to the patient. No other adverse sequelae were experienced by the patient.

Botulinum Toxins in Clinical Aesthetic Practice
264
with a weakened or adynamic depressor labii inferioris must manu­
ally depress the lower lip to open the mouth to eat, drink, and prevent
biting the lower lip while chewing; so as not to dribble, drool, or lose
any oral contents while masticating, the lower lip must be supported
by light manual pressure throughout the entire processes of eating,
drinking, and deglutition. Pronunciation of particular sounds can be
hampered and the articulation of certain words will be difficult. When
the depressor labii inferioris is profoundly affected, a disconcertingly
adynamic smile is likely to occur, with only the upper lip moving.
Overzealous injections with doses over 6–8 U of OnaBTX-A into the
depressor anguli oris also will place patients at risk for developing the
adverse sequelae as described above, even when the injection tech­
nique is flawless, if OnaBTX-A diffuses into the adjacent depressor
labii inferioris. Even when the appropriate dose is precisely injected
into the depressor anguli oris, vigorous massaging of the area after
the injection can displace the OnaBTX-A into adjacent muscle fibers
of the depressor labii inferioris or orbicularis oris and cause similar
adverse effects as described above.
Injections that are too high and either adjacent to or above the men­
tal crease can spread into the muscle fibers of the orbicularis oris and
interfere with its sphincteric function, producing a localized area of
inadequate sphincteric closure of the oral cavity (Figure 15.42d), dif­
ficulty with speech and suction maneuvers (e.g., kissing and drinking
from a straw), and a segmental inability to pucker the lips, whistle, or
perform similar functions (Figure 15.19b).38,39
Injections that are too posterior can affect the buccinator or the
orbicularis oris or both and cause difficulty chewing and swallowing.
Always remain below and far enough away from the mental crease
and the orbicularis oris when treating the depressor anguli oris.
Otherwise, OnaBTX-A can spread focally into the muscle fibers of
the orbicularis oris and result in a localized area of eclabion, an asym­
metric smile, drooling and even dribbling, and a change in speech
and word pronunciation.
Injecting too close to the mental foramen could conceivably cause
damage to the neurovascular plexus and mental nerve emerging
from the mental foramen, resulting in the loss of sensation in the lips
and chin. It may even result in lip biting, difficulty with speech, and
diminished retention of saliva.36 Therefore Hur et al. also concluded
that injecting BTX-A into the lower third of the depressor anguli
oris and below the mental foramen as described above has a lower
risk of direct needle damage to the mental foramen neurovascular
structures and a higher success rate in effectively and safely treating
unwanted melomental folds and the downward pull of the oral com­
missures compared to previously reported injection techniques.36
For the first-time patient, treatment in this area can produce simi­
lar but mild and transient sequelae that may be overwhelming to the
uninformed and unprepared patient, so pretreatment warning of
these potential side effects is mandatory (Figure 15.42).
Figures 15.43 through 15.46 are additional examples of different
patients treated with OnaBTX-A to uplift the oral commissures.
Treatment Implications When Injecting Melomental Folds
and Marionette Lines

1. Inject OnaBTX-A only when the depressor anguli oris can be
unmistakenly identified and accurately palpated.

2. The depressor anguli oris usually can be identified at the infe­
rior end of the nasolabial sulcus over the body of the mandible
and anterior to the masseter.

3. A lateral platysmal band can identify the location where the
depressor anguli oris and platysma pars mandibularis decus­
sate along the inferior border of the mandible. It is at this point
of maximal contraction of the depressor anguli oris that is the
recommended site for an injection of OnaBTX-A.

4. Avoid injecting OnaBTX-A into the marginal mandibular
nerve and facial artery and vein by lifting the skin and soft tis­
sue before injecting.

5. Avoid injecting OnaBTX-A into the depressor labii inferioris
and orbicularis oris by remaining at least 1 cm lateral and 1 to
1.5 cm inferior to the lateral oral commissure and in the center
of or just above the body of the mandible.

6. OnaBTX-A should be injected intramuscularly just beneath
the subcutaneous plane since the lower medial aspect of the
depressor anguli oris is superficial to and overlies the posterior
aspect of the depressor labii inferioris.

7. Always inject minimal doses of minimal volumes of highly
concentrated OnaBTX-A in the perioral area.
CHIN PUCKERING AND A DEEP MENTAL CREASE
Introduction: Problem Assessment and Patient Selection
For some men and especially women, a hyperkinetic mentalis can
produce involuntary localized dimpling (Figure 15.47) or an over­
all puckering of the chin, creating convolutions of deep ridges and
furrows while they speak or convey a particular facial expression
(Figure 15.48). For most individuals who consciously or involuntarily
4
4
(a)
(b)
Figure 15.43  A 45-year-old patient (a) before and (b) 3 weeks after (b) 4 U of OnaBTX-A were injected into each depressor anguli oris. Note the slight uplifting of the
corners of the mouth.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
265
(a)
4
4
(b)
Figure 15.45  A 53-year-old patient (a) before and (b) 3 weeks after 4 U of OnaBTX-A were injected into each depressor anguli oris. Note the slight uplifting of the corners
of the mouth.
(a)
4
4
(b)
Figure 15.44  A 40-year-old patient (a) before and (b) 2 weeks after 4 U of OnaBTX-A were injected into each depressor anguli oris. Note the slight uplifting of the corners
of the mouth.
(a)
4
4
(b)
Figure 15.46  A 78-year-old patient (a) before and (b) after 4 U of OnaBTX-A were injected into each depressor anguli oris. Note the slight uplifting of the corners of the
mouth. This patient also underwent ablative fractionated CO2 resurfacing and injections of soft tissue fillers 2 weeks after the OnaBTX-A injections.

Botulinum Toxins in Clinical Aesthetic Practice
266
crinkle their chin during animation or even while at rest, these
changes generally go undetected by the person producing them
unless disclosed by others. Once identified, chin puckering then can
be verified by the patient personally, viewing these chin corrugations
with a mirror while animating or speaking (Figure 15.49).
Any motion of the lower lip that causes the lip margin to evert as
when pronouncing words that begin with the letter “F” or “V” will
usually accentuate chin puckering (Figure 15.50). In other individu­
als, chin puckering can be a disquieting annoyance when it occurs
postoperatively as a secondary synkinesis from an augmentation
mentoplasty (Figure 15.51a).43,44 Because not all of the bony attach­
ments of the muscle fibers of the mentalis can reposition and reap­
proximate exactly as they were prior to the instillation of a chin
implant, the contracting fibers of the mentalis then become anoma­
lously reattached to the mentum, producing irregular crimping of the
skin surface, either at rest or with each movement of the chin and
mentalis (Figure 15.51a, c). This can be an unexpected and frustrating
side effect for a surgical correction of an inadequately projecting chin.
In still another group of people, a hyperkinetic mentalis produces an
accentuated, deep transverse (labio)mental crease between the lower
lip and the prominence of the chin that amplifies the forward projec­
tion of the apex of the mentum (Figures 15.52 and 15.53). This is viewed
as a sign of dotage or senility by the casual observer, because with age
the tip of the chin can elevate and project forward, producing the so-
called “wicked witch’s chin.” Men are not as frequently bothered by
similar changes and even less often do they seek relief from them.
Functional Anatomy Chin Puckering and a Deep Mental Crease
(see Appendix 2)
Dynamic wrinkling and corrugations of the surface of the chin or the
deep infolding and indentation of a labiomental crease is produced by
a hyperkinetic mentalis. The mentalis is a short, stout, conical, two-
bellied muscle that originates below the depressor labii inferioris on
the anterior aspect of the alveolar mandible on either side of the mid­
line and symphysis menti, at the level of the incisive fossa and root of
the lower lateral incisors and canines (Figure 15.54). It travels obliquely
(a)
(b)
Figure 15.47  (a) This 49-year-old woman was unaware of her chin dimples (arrow) even at rest. (b) 3 weeks after treatment with OnaBTX-A.
(a)
4
4
(b)
Figure 15.48  This 50-year-old was unaware that her chin puckered when she became animated or spoke. (a) Forced contraction of her mentalis produced multidirectional
corrugations before OnaBTX-A, which disappeared (b) 2 weeks after 8 U of OnaBTX-A were injected in her mentalis.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
267
downward, converging its two muscle bellies toward the midline in a
V-shaped triangle to insert with multiple fibrous attachments into the
skin of the apex of the chin on either side of the frenulum of the lower
lip. Some of its other fibers interdigitate superiorly with fibers of the
orbicularis oris and laterally with the fibers of the depressor labii infe­
rioris, contributing to the formation of the mental crease. The mentalis
elevates the skin at the base of the lower lip upward, helping to force
the lower lip against the gums. The mentalis assists other reciprocating
synergistic perioral muscles (e.g., depressor labii inferioris and orbicu­
laris oris) to depress, protrude, and evert the lower lip during drink­
ing, eating, and speaking. These synergistic functional movements
also intensify the indentation of the labiomental crease. The mentalis
also wrinkles the skin of the chin when it is contracted in pouting to
produce an expression of doubt, displeasure, sadness, or disdain. With
age comes the loss of dermal collagen, elasticity, and soft tissue sup­
port. Ageing also promotes the diminution and retrusion of the bony
mentum and a reduction in subcutaneous fat. In conjunction with a
hyperkinetic mentalis, all of these structural changes can facilitate the
appearance of uncontrollable chin convolutions and dimpling. In most
individuals, when frowning in displeasure or projecting an expres­
sion of sadness, doubt, or disdain, the depressor anguli oris contracts
simultaneously with the mentalis, so the melomental (“marionette”)
lines also are accentuated. Therefore, for many patients, it is advisable
Figure 15.49  This 30-year-old was unaware of her chin corrugations until she was
actively animating and puckering in front of a mirror. Note the localized dimpling
of her chin.
4
(a)
(c)
(d)
(b)
Figure 15.50  A 63-year-old woman (a) at rest before 4 U of OnaBTX-A were injected into her mentalis. (b) Note the crimping of the chin and deep mental crease at rest
and while pronouncing words containing the letter “F.” Same patient (c) at rest and (d) 3 weeks after the OnaBTX-A treatment. Note the reduction of chin crimping and
effacement of the mental crease.

Botulinum Toxins in Clinical Aesthetic Practice
268
to treat both the presence of marionette lines and chin dimpling at the
same time during the same session.
Dilution When Treating Chin Puckering and a Deep Mental
Crease (see Appendix 3)
When treating the mentalis, lateral diffusion of the OnaBTX-A runs
the risk of weakening the depressor labii inferioris and producing
sphincter and motor movement incompetence of the mouth, caus­
ing an inability to depress the lower lip when smiling, laughing,
speaking, drinking, and eating. Therefore, accurately reconstituted,
low volumes of concentrated OnaBTX-A must be precisely injected
when treating the mentalis. The preferred way to accomplish this is
to reconstitute a 100 U vial of OnaBTX-A with only 1 mL of normal
saline.
(a)
(b)
(c)
4
4
(d)
Figure 15.51  A 67-year-old (a) before and (b) 6 weeks after her third OnaBTX-A treatment with 8 U of OnaBTX-A into her mentalis for a synkinesis caused by an augmenta­
tion mentoplasty 2–3 years previously. Note the difference in the pattern of chin crimping before and after a treatment with OnaBTX-A. The same patient was plagued with
the appearance of chin crimping both at rest and during animation seen here (c) before and (d) 3 weeks after her fourth treatment of OnaBTX-A.
(a)
(b)
3
3
Figure 15.52  A 52-year-old patient seen (a) before and (b) 1 month after 6 U on OnaBTX-A were injected into the mentalis. Note the slight diminution of the mental crease.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
269
Dosing: How to Correct the Problem (see Appendix 4) (What to
Do and What Not to Do) When Treating Chin Puckering and a
Deep Mental Crease
Injections of the mentalis are best done with the patient in the upright
sitting or semireclined position. A hyperactive mentalis can be relaxed
by inserting the tip of the needle perpendicular to the surface of the
skin and injecting 3–4 U of OnaBTX-A deeply into the muscle at one
point about 5 mm on both sides of the midline into the apex of the
protuberance of the mentum, approximately 1 cm above the tip of the
chin. This two-point injection technique is especially appropriate if
the patient has a vertical mental cleft or a widely shaped, square chin
(Figures 15.51 through 15.53). If the patient has a narrow, rounded, or
a more pointed chin, the insertion of the mentalis into the undersur­
face of the skin with its paired muscle belly of the contralateral side
probably is more centrally located in a narrower, overlapping V-shape.
For these patients, an alternative one-point injection technique is
more appropriate (Figure 15.55). This is accomplished by injecting
4–6 U of OnaBTX-A deeply into one point only into the center of the
mentum at the apex of the mental protuberance, approximately 1 cm
above the tip of the chin (Figure 15.56).
It is imperative to avoid inadvertent diffusion of OnaBTX-A into any
of the muscle fibers of the orbicularis oris, which can result in sphincter
and motor movement irregularities. This can be accomplished by inject­
ing OnaBTX-A significantly lower than the transverse mental crease
and into the center of the apex of the mental protuberance. Light mas­
sage will relieve the pain of injection. Vigorous massage will displace the
OnaBTX-A laterally or superiorly, particularly if the two-injection point
technique is used, and cause the OnaBTX-A to spread into the fibers of
the depressor labii inferioris or the orbicularis oris or both producing
untoward sequelae.
Outcomes (Results) (see Appendix 5)
Relaxing the hyperkinetic muscle fibers of the mentalis can reduce
or eliminate the involuntary convolutions and corrugations of the
chin when one is at rest, speaking, or emotionally expressing one­
self (Figures 15.53 and 15.56). A weakening of the mentalis also can
drop the anterior projection of the skin of the chin slightly downward,
attenuating an already deep transverse labiomental crease and pos­
sibly rotating the lower lip slightly upward (Figures 15.53 and 15.57).
When the transverse labiomental crease is exceptionally deep and
resistant to treatment with OnaBTX-A, elevating and effacing it with
soft tissue fillers is an advisable alternative. Deeply placed injections of
soft tissue fillers across the anterior aspect of the mentum will recon­
tour and rejuvenate the chin. Injections of OnaBTX-A into the men­
talis will actively sustain and prolong the improvement.
For those patients who have a distorted convoluted chin because
of a previous augmentation genioplasty with a chin implant, injec­
tions of OnaBTX-A can produce a softening and a relaxation of
the chin. This is much appreciated by those who are vexed by these
anxiety provoking wrinkles and convolutions of the mentum and
for whom additional surgery is not an option (Figure 15.51). The
addition of a soft tissue filler will augment and prolong the correc­
tive effects produced by the injections of OnaBTX-A. The effects of
the injections of OnaBTX-A of the mentalis can last anywhere from
4 to 6 months.
4
4
(a)
(b)
Figure 15.53  This 58-year-old patient seen (a) before and (b) 3 weeks after 8 U of OnaBTX-A were injected into the mentalis. Note the deep transverse labiomental crease
prior to treatment and its diminution after treatment.
2
1
4
3
Figure 15.54  The mentalis elevates the lower lip, indents the mentolabial crease,
and creates surface corrugations over the mentum: 1, depressor anguli oris; 2,
mentolabial crease (dotted line); 3, mentalis; 4, mentum.

Botulinum Toxins in Clinical Aesthetic Practice
270
(a)
6
(b)
Figure 15.56  A 53-year-old, with chin puckering at rest that was exacerbated with animation, is seen (a) before and (b) 2 weeks after 6 U of OnaBTX-A were injected into a
single site at the apex of the mentum. Note the narrowness of the apex of the mentum and the location of the single injection point.
(a)
4
(b)
Figure 15.57  A 58-year-old patient seen (a) before and (b) 1 month after 4 U of OnaBTX-A were injected into the mentalis. Note the deep transverse labiomental crease
prior to treatment and its slight diminution after treatment.
(a)
4
(b)
Figure 15.55  This 70-year-old woman accentuated chin puckering by pursing her lips (a) before and (b) 1 month after 4 U of OnaBTX-A were injected into a single site at
the apex of the mentum.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
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Complications When Treating Chin Puckering and a Deep Mental
Crease (Adverse Sequelae) (see Appendix 6)
When dosing is excessive or if the injections of an appropriate
amount of OnaBTX-A are placed too high on the lower lip, that is,
above the transverse (labio)mental crease, the orbicularis oris, and
even the depressor labii inferioris can certainly be weakened, par­
ticularly when using the two-point injection technique. Diffusion of
OnaBTX-A into the depressor labii inferioris and orbicularis oris also
can occur when the injections are too superficial or vigorous mas­
saging is performed immediately after injection. If either the orbicu­
laris oris or the depressor labii inferioris is inadvertently affected by
OnaBTX-A, a relaxation of a tight oral sphincter, a reduction in lip
competence, and a diminution in buccal motor movements will occur
(Figure 15.58). This can cause a patient to form certain letters, such
as P, B, W, F, O, and U, and articulate certain sounds and words with
embarrassing difficulty. Also, an asymmetric smile can be produced
because of an adynamic or synkinetic lower lip. An overzealous treat­
ment of the mentalis with too high a dose of OnaBTX-A that virtually
immobilizes the mentalis will cause an inability to evert and approxi­
mate the lower lip tightly against the teeth, or against a glass or cup,
producing a disconcerting predicament with incontinence of solid
food when eating, dribbling from the lower lip when drinking, and
drooling from the corners of the mouth when at rest (Figure 15.58).
Excessive dosing also can inadvertently spread to fibers of the adja­
cent depressor labii inferioris, intensifying the total weakness of the
lower lip, resulting also in a profound inability to depress the lower
lip. When this occurs, the person affected is obligated to manually
lower his or her lower lip to avoid biting it while eating, drinking,
and even speaking. Proper enunciation of speech is temporarily and
overwhelmingly impeded.
Figures 15.59 through 15.63 are additional examples of different
patients treated with OnaBTX-A for chin puckering and a deep men­
tal crease.
Treatment Implications When Injecting the Mentalis

1. Inject OnaBTX-A far below the transverse mental crease and at
the apex of the mental protuberance.

2. Injections should be placed deeply, in one site centrally or in
two sites separately on either side of the midline depending on
the width of the chin.
(a)
(b)
10
Figure 15.58  A 55-year-old patient smiling (a) before and (b) after 10 U of OnaBTX-A were injected into her mentalis. Note the inability of the mentalis to lower the center
of the lower lip after her excessively high dose treatment, which also might have diffused into the depressor labii inferioris. The patient had to manually lower her lip to
avoid biting it while eating and drinking. She had incontinence with liquids and difficulty with articulating certain sounds and words.
(a)
4
(b)
Figure 15.59  This 44-year-old with chin puckering and perioral rhytides is seen (a) before and (b) 3 weeks after 4 U of OnaBTX-A were injected into the mentalis. Note the
softening of the lower face and fullness of the lip vermilion with additional OnaBTX-A injections of the perioral rhytides.

Botulinum Toxins in Clinical Aesthetic Practice
272
(a)
4
(b)
Figure 15.60  A 53-year-old with chin puckering is seen (a) before and (b) 2 months after 4 U of OnaBTX-A were injected into the mentalis. Note the transverse widening
of the mentum. Perioral rhytides were also treated with OnaBTX-A.
(a)
(b)
4
Figure 15.62  A 66-year-old is shown at rest with chin puckering and perioral rhytides (a) before and (b) 2 weeks after 4 U of OnaBTX-A were injected into the mentalis and
additional OnaBTX-A was injected in the perioral rhytides. Note the excessive wrinkling of the lower lip and chin before treatment that softened after treatment.
(a)
4
(b)
Figure 15.61  A 53-year-old with chin puckering is seen (a) before and (b) 6 weeks after 4 U of OnaBTX-A were injected into the mentalis. Note the softening of the lower
face and a fullness of the lip vermilion with the additional treatment of her perioral rhytides with onaBTX-A.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
273

3. High-volume injections or an improper heavy-handed tech­
nique can cause the spread of OnaBTX-A into the depressor
labii inferioris or the orbicularis oris or both, and result in an
inability to move the lower lip inferiorly, causing sphincter
incompetence of the buccal aperture.

4. Immobilizing the mentalis with a high dose of low-volume
OnaBTX-A can prevent the lower lip from approximating
tightly against the teeth or a drinking vessel, resulting in drib­
bling while drinking and drooling while at rest. Inability to
articulate words and sounds distinctly also can occur.

5. Injections of OnaBTX-A can correct postoperative chin
puckering and distortions resulting from an augmentation
mentoplasty.

6. The use of OnaBTX-A can prolong the enhancement produced
by soft tissue filler injections of the perimental and perioral
areas.

7. OnaBTX-A treatment of the lower face and perioral area should
always include injecting the mentalis.
JAWLINE BLUNTING AND WRINKLING OF THE
PERICOMMISSURAL AREA AND LOWER MANDIBULAR BORDER
Introduction: Problem Assessment and Patient Selection of
Jawline Blunting and Wrinkling of the Upper Platysma
With age, the effects of gravity, genetics, and the environment cause
our skin to slacken and become redundant as we lose dermal elastic­
ity. There is a descent of soft tissue from the mid face toward the man­
dibular border.45 With time, the platysma can become hyperkinetic
and the skin of the face and neck becomes lax and drapes randomly in
the lower face, over the mandibular border, overhanging and blunting
the cervicofacial angle (Figure 15.64a). Patients who can elevate their
platysma, blunting their sharp mandibulocervical angle by pulling
down hard on their platysma are ideal candidates for treatment with
OnaBTX-A (Figure 15.64b).
In addition, there is a small subset of patients whose upper pla­
tysma is very active and hyperkinetic creating various types of lower
face wrinkling. For example, one type of hyperkinetic platysmal lower
face wrinkling can be attributed to the long-term changes occurring
4
4
(a)
(b)
Figure 15.63  A 38-year-old at rest with a deep transverse mental crease (a) before and (b) 3 weeks after 8 U of OnaBTX-A were injected into the mentalis. Note the efface­
ment of the mental crease and upward rotation of the lower lip vermilion.
(a)
(b)
Figure 15.64  (a) This patient has a hyperkinetic platysma, creating a blunting of the cervicofacial angle. (b) Same patient tightening her platysma and further blunting the
cervicofacial angle.

Botulinum Toxins in Clinical Aesthetic Practice
274
after a surgical rhytidectomy. These patients by grimacing can form
different atypical wrinkles parallel to the mandibular border, which
are produced by the compensatory contractions of the mandibular
platysma (pars mandibularis) as it becomes hypertrophic and more
active with time (Figure 15.65a, b).
Still another type of lower face wrinkling attributed to a hyper­
kinetic mandibular platysma are the naturally occurring pericom­
missural horizontal lines, which become visible with the slightest
bit of buccal movement. These lines in particular will deepen with
smiling or laughing and are an annoyance to those who possess them
(Figure 15.66). Lower facial platysmal lines become more obtrusive
when their bearer loses weight and the lower facial skin continues to
become lax and inelastic with time and progressive photoaging.
Functional Anatomy of the Upper Platysma (see Appendix 2)
The platysma is composed of two separate paired broad, flat, thin
sheets of muscle originating over the chest and shoulders, extending
over the full length of the neck. It continues up the frontal and lat­
eral aspects of the neck subcutaneously from the upper chest to the
mandible, fusing and blending its paired muscle fibers just below the
chin, and participating in the formation of the superficial musculo-
aponeurotic system (SMAS) in the lower, lateral and superior aspects
of the face (Figure 15.67).46–50 The platysma can vary considerably
in thickness and extent; in general, women have a thinner platysma
than men.51 In some individuals, the platysma may even be absent.
The platysma ascends obliquely upward and inward in a superome­
dial direction from the upper anterior thorax and deltoid, and later­
ally from across the clavicle and acromion of the scapula and up the
lateral neck. It continues up the anterior and lateral aspect of the neck
and inserts into the chin anteriorly, while laterally, it inserts above the
mandible into the anterior one third of the oblique line of the man­
dibular ramus (Figures 15.10 and 15.67). The more posterior fibers
of the lateral platysma partially cover and interdigitate with fibers of
the sternocleidomastoid, running posterior to it. Then some of these
posterior platysmal fibers assume a more anterior course, while tra­
versing over the lower border of the mandible, and pass superficially
over the marginal mandibular branch of the facial nerve, artery, and
vein and insert into the oral commissures. These posterior superior
muscle fibers of the platysma move in a “lazy S” configuration as they
travel from the chest, up the neck, over the mandible, onto the lower
face and into the corners of the mouth (Figures 15.9 and 15.67).52 The
platysma can reach as high as the ear or zygoma because it then joins
the layers of the temporalis fascia over the zygomatic arch near the
origin of the zygomaticus major which it envelopes and can continue
up to the margin of the orbital orbicularis oculi. This is because as the
plastysma continues cephalad from the neck onto the face it is indis­
tinguishable from and persists as the SMAS of the face.48,49
The upper portion of the platysma muscle, before it becomes an apo­
neurosis and part of the SMAS, is composed of three parts, the mandib­
ular, labial, and modiolar parts, and functions as an accessory muscle
(a)
(b)
(c)
Figure 15.65  (a) This 68-year-old has a very active upper platysma which creates a set of perioral horizontal rhytides with the slightest buccal movement. Same patient
is seen grimacing prior to (b) 20 U of OnaBTX-A that were injected 2–4 mm above and below the inferior border of the body of the mandible. (c) Same patient shown 1
month after treatment.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
275
to the orbicularis oris complex4 (Figures 15.7, 15.9, and 15.67). The
upper fibers of the platysma identified as the platysma pars mandibu­
laris insert onto the lower border of the mandible below the oblique line
and into the skin and subcutaneous tissue of the lower part of the face
(Figures 15.10 and 15.67). Posterior to this attachment, a substantial
number of flattened muscle bundles separate and pass superomedially
to interdigitate with muscle fibers of the lateral border of the depressor
anguli oris (Figure 15.9). Other fibers of the platysma pars mandibu­
laris travel deep to the depressor anguli oris and re-emerge medial to it.
Some of these medial platysmal fibers known as the platysma pars
labialis continue within the tissue of the lateral half of the lower lip, as
a direct labial retractor. The pars labialis occupies the interval space
between the depressor anguli oris and depressor labii inferioris, and
is in the same tissue plane as both of these muscles. The adjacent mar­
gins of all three muscles interdigitate with each other and have simi­
lar labial dermal attachments. They then also blend into some of the
muscle fibers surrounding the buccal commissures (orbicularis oris
and risorius) and the chin (mentalis) (Figures 15.67).
The platysma pars modiolaris is comprised of all the remaining
muscle fibers of the upper platysma posterior to the platysma pars labi­
alis other than a few fine fascicles that end directly into buccal dermis
or submucosa. The pars modiolaris is posterolateral to the fibers of the
depressor anguli oris. They pass superomedially, deep to the risorius
and into the apical and subapical modiolar attachments4 (Figure 15.7).
The platysma slightly depresses the mandible, partially opening the
mouth during an expression of surprise. The platysma also is active
(a)
(b)
(c)
2
2
2
5
(d)
Figure 15.66  This 55-year-old has lower face platysmal lines due to aging and weight loss. Patient is seen before (a, c) and 3 weeks after (B, D) 6 U of OnaBTX-A were injected
into the platysma pars mandibularis along the inferior border of the mandible. The mentalis was injected with 5 U of OnaBTX-A and a hyaluronic acid soft tissue filler was
injected into the nasolabial folds during the same treatment session.
Figure 15.67  Anterolateral view of the extent of platysma (pars mandibularis, pars
labialis, and pars modiolaris), from its origin in the chest and pattern of ascent, to
insertion along the mandible. (Note that only the right side of platysma is shown
here; the left side has a paired symmetrical extent.)

Botulinum Toxins in Clinical Aesthetic Practice
276
during sudden, rapid, and deep inspiration. The anterior portion and
thickest fibers of the platysma can pull the lower lip and corners of
the mouth downward and laterally, widening the buccal aperature at
the corners of the mouth as in an expression of horror. Contracting
the platysma can increase negative pressure in the superficial jugular
veins of the neck, facilitating venous circulation. Electromyographic
studies have demonstrated that the platysma is not actively contract­
ing during laughing, opening the mouth, or moving the head.40,46,47
However, deliberate maximum contraction of the platysma pulls the
skin lying over the clavicles upward and wrinkles the skin of the neck
in an oblique direction increasing the diameter of the neck, as one
does when relieving the pressure of a tight collar. Platysmal cords and
bands also may be unmasked with this maneuver in those so predis­
posed to develop them (see Vertical Bands below).
Dilution (see Appendix 3) When Treating Jawline Blunting and
Wrinkling of the Upper Platysma
When treating the upper fibers of the platysma, it is safer and results will
be more consistent if small volumes of OnaBTX-A are injected. This will
avoid any unintended diffusion beyond the targeted thin muscle fibers
of the platysma. Therefore, a 100 U vial of OnaBTX-A is best recon­
stituted with 1 mL of normal saline. If a more far-reaching technique
simulating the “microbotox” technique is desired (Chapter 17 by Dr.
Seo), then a 100 U vial of OnaBTX-A can be reconstituted with 2–5 U
of normal saline. This more highly diluted OnaBTX-A should only be
injected with the small volume, intradermal, microinjection technique.
Dosing: How to Correct the Problem (see Appendix 4) (What to
Do and What Not to Do) When Treating Jawline Blunting and
Wrinkling of the Upper Platysma
The platysma plays a predominant role in the overall contour of the
mandibular border and the cervicofacial angle. It also is responsi­
ble for the horizontal wrinkles seen just below and adjacent to the
modiolus and the oral commissure (Figure 15.66). To treat either
the blunting of the jawline or the horizontal wrinkles lateral to the
mentum and inferior to the oral commissure along the upper man­
dibular border, place the patient in a sitting or semireclined position.
Because of the intricate way the upper platysma interdigitates with
the muscles of the lower face above the mandible, those horizontal
rhytides that become more prominent when the corners of the mouth
are compressed by the contraction of the modiolar area should be
treated with injections of onaBTX-A only submandibularly and never
over or above the body of the mandible. These horizontal lines along
the upper border of the mandible frequently are caused mainly by the
platysma mandibularis and platysma labialis, and occasionally rein­
forced by the platysma modiolaris. Place 2–3 U of OnaBTX-A in the
upper neck, approximately 1.5–2.0 cm below the inferior margin of
the mandible and directly beneath those horizontal wrinkles in 2–4
injection points 1.5–2.0 cm apart from each other (Figure 15.66). The
injections should begin just lateral to the bony origin of the depressor
labii inferioris and not any more anterior to this point. These injec­
tions usually should be performed at the same time the depressor
anguli oris and mentalis are treated, since these muscles all interdigi­
tate and function codependently with each other.
In addition, Levy found that he could delineate more sharply the
mandibulocervical angle by injecting 2–3 U of OnaBTX-A at mul­
tiple sites along the upper cervical border of the platysma just adja­
cent and inferior to the mandibular border and over the entire lateral
side of the neck in patients who did not need a lower face or cervi­
cal rhytidectomy. He called this injection technique the “Nefertiti”
lift (Figure 15.68).53,54 These injections should begin no higher than
1.5–2.0 cm beneath the mandibular border just underneath and lat­
eral to the bony origin of the depressor labii inferioris. This places the
first injection point directly beneath the bony origin of the depres­
sor anguli oris. Continue the injections along the upper border
and over the entire lateral side of the neck. However, the injections
should not cross over the anterior border of the sternocleidomastoid
(Figure 15.69). The total dose for each lateral side of the neck should
not exceed more than 20–25 U of OnaBTX-A, that is, a total dose of
40–50 units of OnaBTX-A on both sides of the entire neck during
any given treatment session. If there are prominent platysmal bands
in the anterior and lateral neck, they also should be included in the
treatment of this “Nefertiti lift” (Figure 15.68a,b) (see Vertical Bands
below and Figure 15.69a,b).
The platysma with or without platysmal bands in the submandibular
area of the lateral neck can be easily treated by grasping skin or the band
with the thumb and index finger of the nondominant hand and inject­
ing 2–3 U of OnaBTX-A between those fingers in a “T”-like pattern
along the lateral side of the neck. Six to a maximum of 8 points of injec­
tion along one lateral side of the neck is sufficient to produce a Nefertit
(a)
(b)
2
2
2
2
2
2
Figure 15.68  (a, b) Note the multiple injection points along the upper cervical border of the platysma, along the lateral aspect of the neck. Approximately 2 U of OnaBTX-A
were injected at each point (wheal).

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
277
lift. Eight to a maximum of 12 points of injection along one lateral side
of the neck is sufficient to diminish prominent platysmal banding when
they are present. (Figures 15.68, 15.69, and 15.79).
Outcomes (Results) When Treating Jawline Blunting and
Wrinkling of the Upper Platysma (see Appendix 5)
Hyperkinetic platysma and inelastic, saggy skin cause blunting of
the jaw line. Injections of OnaBTX-A along the inferior border of
the mandible and down the lateral sides of the neck relax the upper
lateral platysma and pars mandibularis, allowing the levators of
the face to lift the skin of the lower face and upper neck. This in
turn redefines the mandiblar border and sharpens the mandibulo­
cervical angle closer to 90 degrees by redraping the skin over the
jaw line for a tighter, more youthful, contoured appearance. This
technique also elevates the corners of the mouth giving the over­
all visual effect of a “mini-lift” of the lower face and upper neck53
(Figures  15.70,  15.71, and 15.74). Levy named this technique the
“Nefertiti lift” to emphasize the final visual effect of an elegant, per­
fectly recontoured jawline similar to that of the famous bust of the
Egyptian Queen Nefertiti (Figure 15.72).
Figure 15.69  The injection points are posterior to the lateral border of the depres­
sor anguli oris (dashed lines) and anterior to the belly of the sternocleidomastoid
(red dashed lines).
(a)
(b)
(c)
2
4
2
2
2
2
2
(d)
2
2
2
2
2
2
4
Figure 15.70  (a) A 59-year-old patient is seen (a) before and (b) 2 weeks after 12 U of OnaBTX-A were injected in her left plastysma, pars mandibularis and left depressor
anguli oris. Same patient is seen (c) before and (d) 2 weeks after the identical treatment with OnaBTX-A was completed on the right.

Botulinum Toxins in Clinical Aesthetic Practice
278
For those horizontal platysmal wrinkles lateral to the mentum
and inferior to the oral commissures, a treatment with 4–8 U of
OnaBTX-A will diminish them, and the results can last 3–4 months
(Figures 15.65 and 15.66). Levy, however, reports the effects of the
“Nefertiti lift” to last even longer, an average of 6 months.53
Complications When Treating Jawline Blunting and Wrinkling of
the Upper Platysma (Adverse Sequelae) (Appendix 6)
Injecting the platysma pars mandibularis is no easy task and
should only be performed by the expert injector. If there is diffu-
sion of OnaBTX-A beyond the immediate site where it is injected,
the depressor labii inferioris, the orbicularis oris, and other seg-
ments of the platysma will be affected, which can adversely impact
the final results (Figure 15.73). In addition, if OnaBTX-A is injected
unevenly or if it is taken up by the different muscle fibers of the
platysma that interdigitate with the lower lip depressors, then an
asymmetry and a malfunctioning of the mouth and distortion of
the lower face will be experienced by the patient (Figure 15.73).
This can occur when performing the Nefertiti lift or when one
attempts to eliminate the horizontal lines of the lateral mentum
inferior to the oral commissures. Injections too close to the infe-
rior border of the mandible and too far anteriorly, that is, directly
under the origin of the depressor labii inferioris will cause lower lip
fuctional disturbances, as was also seen in de Almeida’s recent ret-
rospective study81 and first described in the previous edition of this
text (Figure 15.73).82 Other predictable adverse sequelae that can
occur when injections of OnaBTX-A are not placed properly in the
neck are an asymmetric smile, disruption of lip competence caus-
ing incontinence of food and liquids, dysarthria, disphonia, and
dysphagia. When treating the platysma pars mandibularis along
the inferior mandibular border posteriorly, OnaBTX-A should not
inadvertently penetrate the sternocleidomastoid either by direct
injection or unintentional spread. If this occurs, the patient will
have difficulty with lateral and rotational movements of the neck,
resulting in an instability of head positioning and difficulty raising
it from a supine position.
When treating the lower face and the platysma, there is an exqui-
sitely delicate balance of levators and depressors just like in the mid-
face, that is, a narrow margin of dosing for successful and uneventful
outcomes. Increasing a proven efficacious dose of OnaBTX-A by 1 or
2 U may cause adverse sequelae when a lower dose did not. Therefore,
only a minimal amount of concentrated, low volume OnaBTX-A
should be injected in the mid and lower face, if predictable and
reproducible beneficial treatments without adverse side effects are
expected. Most importantly, when treating the platysma in the lower
face, keep the injections superficial (i.e., intradermal) and far away
from the orbicularis oris and depressor labii inferioris.
(a)
(b)
4
2
2
2
2
2
2
Figure 15.71  A 58-year-old patient is seen (a) before and (b) 2 weeks after 12 U of OnaBTX-A were injected in her left platysma, pars mandibularis and left depressor
anguli oris.
Figure 15.72  The world-renowned statue of Nefertiti, currently housed at the
Neues Museum in Berlin, illustrates the ideal cervicofacial angle of 80°–95°.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
279
Treatment Implications When Injecting the Jawline and
Upper Platysma

1. Horizontal rhytides just lateral to the mentum and oral com­
missures can be diminished by intradermal injections of
OnaBTX-A only along the undersurface of the mandible and
never above it.

2. Hyperkinetic fibers of the upper platysma (pars mandibularis)
can blunt the jawline.

3. Properly placed intradermal injections of OnaBTX-A along
the underside of the mandible and down the lateral neck can
sharpen the jawline and lift the skin of the lower face and upper
neck.

4. Injections of the submandibular upper platysma with
OnaBTX-A should be performed posterior to the origin of the
depressor labii inferioris and 2–3 cm inferior to the lower bor­
der of the body of the mandible.

5. Avoid injecting the stermocleidomastoid by placing the injec­
tions of OnaBTX-A in the lateral neck in front of the anterior
border of the muscle to prevent difficulty with neck movements
and head positioning.

6. For optimal results, the lower face should be treated as one cos­
metic unit with injections of OnaBTX-A placed intradermally
in the superficial labial orbicularis oris, deeply into the men­
talis, subcutaneously and intramuscularly into the depressor
anguli oris, and intradermally in the upper platysma.

7. Avoid injecting the depressor labii inferioris and the deep fibers
of the orbicularis oris with OnaBTX-A to prevent oral sphinc­
ter incompetence and a disruption in buccal function.
HORIZONTAL LINES AND VERTICAL BANDS OF THE NECK
Introduction: Problem Assessment and Patient Selection
Frequently, the neck can be a more accurate gauge of a person’s
­chronologic age than the overall appearance of his or her face. This
is ­especially true in those individuals who have spent a lot of time
outdoors and who have taken advantage of various cosmetic proce­
dures available to rejuvenate their faces. The neck as well as the peri­
oral region have remained the bane of aesthetic rejuvenation for most
age-conscious individuals seeking relief from the ravages of time and
the innumerable hours spent outdoors, whether for work or pleasure.
None of the available invasive surgical procedures (i.e., cervicoplasties
(a)
(b)
Figure 15.73  (a, b) This patient experienced asymmetry of the lower right pars peripheralis of the lips and distortion of the lower face after submandibular injections of
OnaBTX-A diffused into the right depressor labii inferioris. Note the synkinesis of the levators in the upper lateral quadrant. The right submandibular injection was placed
anterior to the posterior border of the depressor anguli oris and possibly too close to the lower edge of the mandible.
4
(a)
(b)
2
2
2
2
2
2
Figure 15.74  (a) This 66-year-old patient is seen before (a) and 3 weeks after (b) 12 U of OnaBTX-A were injected in her left platysma, pars mandibularis, and 4 U of
OnaBTX-A were injected in her left depressor anguli oris.

Botulinum Toxins in Clinical Aesthetic Practice
280
or rhytidectomies) have ever eliminated satisfactorily and safely hori­
zontal necklace lines or vertical platysmal bands for any substantial
length of time.53 Since the 1990s, more innovative and aggressive
approaches to neck rejuvenation have been introduced, albeit not as
invasive as a surgical intervention. These include minimally invasive
suture-based suspensory thread-lifting techniques and superficial
skin surface altering procedures, for example, chemical peeling or
ablative and nonablative fractionated laser resurfacing. A multitude
of transepidermal and subdermal approaches to facial and neck reju­
venation have become popular, including sequential treatments with
nonablative laser and light devices, for example, pulsed dye laser and
polychromatic intense pulsed light, radiofrequency (RF) and high-
intensity focused ultrasound (HIFU). The routine use of energy-
based treatments in combination with BoNT, soft tissue fillers and
implants, and daily topical treatments with cosmeceuticals is prob­
ably the only way to effectively maintain a harmoniously youthful
appearance of the neck with the rest of the face.55 (See Carruthers,
Chapter 7.)
With age, the skin of the neck progressively loses its elasticity,
becoming increasingly lax and redundant. There also is a diminution of
soft tissue support, causing the skin of the neck to be susceptible to fre­
quent and continuous horizontal creasing in some individuals. These
idiosyncratic movements of the neck can lead to persistent transverse
wrinkles that are perpendicular to the normal vertical contractions of
the platysma. These horizontal lines traverse the anterolateral aspect
of the neck between the anterior borders of the right and left sterno­
cleidomastoid, which start just below the submandibular border and
continue downward toward the clavicles like multiple parallel rings
around the neck, also referred to as “necklace lines” (Figure 15.75).
A hyperkinetic anterior platysma also produces the detested pla­
tysmal neck bands, whether a person is actually at rest or intention­
ally tightening their neck muscles. Upon animation with different
neck movements, vertical bands and cords may become prominent
at an early age (in the fourth or fifth decade) in predisposed indi­
viduals or eventually in the sixth or seventh decade for many others
(Figures 15.76 and 15.77). Neck bands are caused by the platysma and
not by the skin of the neck, whether the skin is inelastic or lax.5 When
an individual’s platysma is hyperkinetic, anterior neck bands will be
noticeable even when that person is at rest. Intentionally contracting
the platysma will intensify these bands significantly.
When the platysma becomes less elastic with age, it separates
anteriorly and can be appreciated clinically as two or more diver­
gent bands or folds of skin that extend from the lower margin of the
mandible to the medial aspect of the clavicles. These anterior neck
bands often tighten and become more visible, especially when the
patients turn the head from side to side as they speak or gesticulate
(Figure 15.76).56 Vertical bands and cords develop as the result of
a hyperactive platysma attempting to support the ptotic structural
(a)
(b)
Figure 15.75  (a, b) This 55-year-old began to notice deep horizontal wrinkles of the anterior neck at age 40.
(a)
(b)
(c)
Figure 15.76  (a, b, c). This 52-year-old began to notice deep horizontal wrinkles of the anterior neck at age 38. Note the platysmal neck bands when she forcibly contracts
her platysma.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
281
changes so characteristic of a senescent neck. The anterior edges of
the fibers eventually lose muscle tone, separate over time, and pro­
trude anteriorly, creating the cords and bands that are sometimes
referred to as the “turkey neck” deformity52 (Figure 15.77). For some
carefully selected individuals who still possess a reasonable amount
of cutaneous elasticity, but who develop prominent platysmal neck
bands because of idiosyncratic platysmal hyperactivity, injections
of OnaBTX-A have become a viable treatment option to reduce the
prominence of those platysmal neck bands. For others demonstrat­
ing a similar integrity of cutaneous elasticity, but who either are
unable for medical reasons or are unwilling for other personal rea­
sons, to undergo the burden of the postoperative morbidity of an
invasive surgical procedure such as a cervicoplasty or rhytidectomy,
injections of OnaBTX-A have become a frequently requested and
reliable solution to their problem.
Functional Anatomy of Horizontal Lines and Vertical Bands
of the Neck (see Appendix 2)
The platysma is composed of two separate paired broad, flat, thin
sheets of muscle originating from the superficial fascia of the upper
part of the thorax over the pectoralis major and deltoid, extending
over the full length of the neck. In certain patients, the platysma can
originate lower than the second, and as far down as the fourth to the
sixth intercostal space (Figure 15.67). It continues running up the
frontal and lateral aspects of the neck subcutaneously from the upper
chest to the mandible, fusing and blending its paired muscle fibers
just below the chin, and participating in the formation of the SMAS
in the lower, lateral and superior aspects of the face (Figure 15.67).46–49
The platysma can vary considerably in thickness and extent; in gen­
eral, women have a thinner platysma than men.51 In some individu­
als, the platysma may even be absent.
The platysma ascends obliquely upward and inward in a superome­
dial direction from the upper anterior thorax and deltoid, and later­
ally from across the clavicle and acromion of the scapula and up the
lateral neck. It continues up the anterior and lateral aspect of the neck
and inserts into the chin anteriorly, while laterally, it inserts above the
mandible into the anterior one third of the oblique line of the man­
dibular ramus. The more posterior fibers of the lateral platysma par­
tially cover and interdigitate with fibers of the sternocleidomastoid,
running posterior to it. Then some of these posterior platysmal fibers
assume a more anterior course, while traversing over the lower border
of the mandible, and pass superficially over the marginal mandibular
branch of the facial nerve, artery, and vein and insert into the oral
commissures (Figures 15.9 and 15.67).
The medial, anterior fibers of the platysma in the neck are the most
variable. Both sheets of the anterior fibers of the platysma on either
side of the neck converge at the level of the thyroid cartilage and form
an inverted “V,” decussating at various levels in the submental area or
directly under the chin at or near the symphysis menti of the mandi­
ble. Consequently, the submental area can be either totally covered or
even devoid of muscle fibers of the platysma.49,52,57,58 Some authors like
to emphasize the different anatomic variations of the platysma based
on the pattern of decussation of its interlacing fibers as they approach
the submental region (Figure 15.78b).48,49,52,57,59–61 One can appreciate
from many of the existing anatomical studies in the literature why
some individuals develop platysmal neck bands and cords, while oth­
ers do not. Most of these reports are of cadaver dissections, and they
differ according to race, sex, and age of the cadavers, depending on
the country in which the study took place. One of the first and fre­
quently referred to studies of cadaver dissection was that of Cardoso
de Castro. In 1980, he characterized the various configurations of the
anterior, medial muscle fibers of the platysma based on his dissec­
tion of 50 cadavers, in which he observed three patterns of platysmal
decussation.57 The most common variant was seen in approximately
75% of the cadavers. Identified as type I, the fibers of the platysma
showed convergence and decussation with its counterpart from the
opposite side of the neck 1–2 cm below the chin. Another 15% of the
cadavers (type II) showed muscle fibers which decussated at the level
of the thyroid cartilage and became a unified sheet of muscle from
thereon up and over the entire submental region. Only type III, or
10% of the cadavers, demonstrated two separate straps of platysma
which ran parallel to each other up the neck, attaching to the under­
surface of the chin and mandible and into the skin without decussat­
ing its fibers (Figure 15.78b).46,57,60–63
Pogrel et al. in their later study categorized four similar but differ­
ent patterns of anterior platysma decussation.58 Approximately 40%
of their cadavers had platysma fibers from the level of the thyroid car­
tilage converging in the center of the neck just beneath the chin, but
they did not decussate. They formed what they called a “V-shaped
dehiscence.” Another 35% of their specimens, converged lower in
the center of the neck; however, these muscle fibers criss-crossed
over the midline, decussating with each other, also in a “V-shaped
dehiscence.” These two groups of “V-shaped dehiscence” (75%) seem
to correspond to Cardoso de Castro’s group I cadavers. Another 15%
of the cadavers in the Pogrel et al. study showed total interdigitation
of platysmal fibers in the midline throughout the submental region.
In this group, no area in the submental region was free of muscle and
there were no free borders of dehisced platysma fibers. Their submen­
tal area was completely covered in a sheet of muscle forming a sub­
mental sling or what they considered a platysmal “diaphragm.” These
were the patients who were least likely to form platysmal bands, even
with advancing age. In the final 10% of their cadavers, Pogrel et al.
found the right and left platysma were the farthest apart from each
other, but eventully merged and interdigitated with each other closest
to the chin in a “U-shaped dehiscence” rather than in a “V-shaped
dehiscence. They felt that this configuration of the submental area
was the freest of muscle and had the greatest potential for a “turkey
Figure 15.77  Note the pendulous “turkey neck deformity” in this 73-year-old
woman.

Botulinum Toxins in Clinical Aesthetic Practice
282
neck” deformity.58 These results are similar to what Cardoso de
Castro found in 10% of his cadavers where both sides of the platysma
approached the menton without prior decussation.
The simplest explanation why some people develop platysmal bands
and chords and others do not is that, according to Vistnes et al.52 and
Hoefflin,49 there are just two basic decussating configurations of the
platysma in the anterior neck. Vistnes et al. found in approximately
60% of their cadavers that the free medial borders of the paired pla­
tysma formed an inverted “V” around the prominence of the thyroid
cartilage, with its apex at the hyoid bone (Figure 15.78a). At the level
of the hyoid bone, the muscle fibers decussated across the midline,
forming a sling from the hyoid bone to the tip of the chin (menton)52
(Figure 15.78b). Hoefflin further simplified the classification of the
platysma as either decussating two-thirds of the time, or not at all.49
There are two distinctly separate depots of fat in the submental
region of the neck that must be taken into consideration when plan­
ning rejuvenation procedures for the aging neck. The more superfi­
cial one of the two is the submental or submandibular fat pad, which
lies directly anterior to the platysma in the subcutaneous plane. The
other, the subplatysmal fat pad, lies more deeply in the neck, resid­
ing behind and posterior to the platysma. Herniation and protrusion
of the subplatysmal fat pad in the aging neck are predicated on the
type of anatomic variant and amount of platysmal central dehis­
cence present in an individual and whether there is a significantly
wide enough separation of the two muscle sheets inferior to the men­
tum. In those individuals with excessive amounts of submental fat
in the subplatysmal layer, the loss of platysmal muscle tone permits
the subplatysmal fat pad to herniate through the free borders of the
platysma and establish a central fullness of submental fat in between
vertical columns of neck bands, blunting a youthful 110-degree
cervico-mental angle and creating the so-called turkey neck defor­
mity50,52 (Figure 15.77).
The submandibular salivary glands are secondary salivary glands
which measure approximately 3 × 5 cm and are located one-third of
the way between the chin and mastoid process and are found in the
lateral floor of the mouth, positioned under the border of the mandib­
ule.55 With time, the gland becomes enlarged and ptotic and can herni­
ate through a weakened or attenuated platysma. This creates a small
bulge at the sides of the neck, characteristic of someone of advanced
age. Injections of OnaBTX-A can contribute to this deformity by
decreasing the support of the platysma and superficial cervical fascia.
However, direct injections of OnaBTX-A into the body of the subman­
dibular glands are somewhat successful in reducing the size of enlarged
and ptotic submandibular glands and minimizing their appearance for
(b)
Type I
Type II
Type III
(a)
Epiglottis
Hyoid bone
Thyroid cartilage
Circoid cartilage
Trachea
Anterior view
Figure 15.78  (a) Anatomical landmarks of the anterior neck. (b) Three types of decussating platysma. (From Brennan PA, Mahadevan V, Evans BT, Clinical Head and Neck
Anatomy for Surgeons, CRC Press: Boca, 2016, with permission.)

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
283
prolonged periods of time.55 Such BoNT-A treatments usually are per­
formed more frequently in the East64 (see Chapter 17 by Kyle Seo).
Dilution When Treating Horizontal Lines and Vertical Bands of
the Neck (see Appendix 3)
Because the platysma is a large sheet of muscle that drapes over the
anterolateral aspect of the neck, injections of large volumes of dilute
OnaBTX-A may be more expedient when the entire neck needs to
be treated. Therefore, reconstituting a 100 U vial of OnaBTX-A with
2–4 mL of normal saline is more practical than reconstituting it with
a smaller volume when injecting the platysma.
Dosing: How to Correct the Problem (see Appendix 4) (What to
Do and What Not to Do) When Treating Horizontal Lines and
Vertical Bands of the Neck
To eliminate most of the dynamic horizontal lines of the neck, inject
approximately 2–3 U of OnaBTX-A above and below the entire ante­
rior and lateral extent of the main horizontal line at points 2–3 cm
apart into the deep dermis, rather than the subcutaneous plane
(approximately 2–3 mm deep), using dilute volumes of OnaBTX-A.
Elevated wheals will confirm that the injections were placed cor­
rectly. Repeat this technique above and below the other horizontal
lines along the anterior and lateral aspects of the neck. Injections are
performed with the patient sitting upright or in a semireclined posi­
tion and forcibly contracting their platysma by clenching their teeth
(Figure 15.76). Depending on the size of the patient’s neck, no more
than 25–35 U of OnaBTX-A should be given at any given treatment
session for this indication.65
In the properly selected patient, OnaBTX-A also can be used to
reduce the appearance of vertical bands and cords of the neck.37–
39,41–43,56,66 In those patients with extensive cutaneous laxity and
flaccid platysmal cords, injections of OnaBTX-A can actually cause
the patient to appear worse, and therefore should not be attempted
(Figure 15.77).
Again, with the patient sitting upright or in a semireclined position
and contracting their platysma, grasp the platysmal band between
the thumb and index finger of the nondominant hand (Figure 15.79).
Inject 2–3 U of OnaBTX-A intradermally, or just subcutaneously
(2–3 mm deep) into each injection site along the vertical extent of
the band. Start the injections approximately 2 cm below the inferior
border of the mandible centrally in the submental area, 1–2 mm lat­
eral to the origin of the depressor labii inferioris or posterior to the
mandibular retaining ligament. This technique avoids the spread of
OnaBTX-A into the lower fibers of the depressor labii inferioris and
may prevent unexpected visible distortions of the chin and func­
tional disturbances of the lower lips. Repeat each injection at inter­
vals of 1.5–2 cm from each other, descending down the neck toward
the upper border of the clavicle, stopping at the level of the thyroid
cartilage.5,60 Raising a visible wheal with each injection attests to
the appropriately superficial placement of the injected OnaBTX-A
(Figure 15.80). Keeping the injections as superficial as possible will
avoid postinjection ecchymoses that result from puncturing super­
ficial vasculature of the muscle. The application of ice to the area
before and especially immediately after injecting OnaBTX-A as well
as gentle massage helps to alleviate some of the pain that accompanies
an intracutaneous injection. It also may help reduce the potential for
bruising. Most patients require 3–5 injection points along the verti­
cal length of a platysmal band to treat it adequately, and some may
require even more, depending on the length of their neck. It is advis­
able to inject no more than 6–12 U of OnaBTX-A along the vertical
extent of each platysmal band for a total of 30 to 50 U per treatment
session when two or three neck bands are treated on both sides of the
neck.46 When more than two platysmal bands are present on each side
of the neck, the other platysmal bands should be treated at another
treatment session, 2–4 weeks later, especially if more than 50 U of
OnaBTX-A have already been injected. When the neck bands pres­
ent as thick cords and a hypertrophic platysma can be palpated, an
additional 1 or 2 units of OnaBTX-A can be applied at each injection
point. Some authors have injected as much as 200 U per treatment
session in the same patient, a practice that is not necessary in most
cases.62,63 There are others who use electromyographic guidance to
accurately place a minimum amount of OnaBTX-A in a platysmal
band when treating the neck. By utilizing electromyographic guid­
ance, they can use less than a total of 20 U of OnaBTX-A in the neck
of a patient in any given treatment session.67
Outcomes (Results) When Treating Horizontal Lines and Vertical
Bands of the Neck (see Appendix 5)
Relaxation of a hypertrophic platysma with diminution of horizontal
neck lines and vertical bands will occur 5–7 days after a treatment
with OnaBTX-A. The effects can last anywhere from 3 to 5 or more
months, depending on the precision of the injections, the strength of
the platysma, and the frequency and intensity of the patient’s neck
movements. Usually patients who are too young for rhytidectomies
or older patients who have had rhytidectomies and have minimal skin
excess will have the best results when there is reasonably tight cutane­
ous elasticity and minimal ptosis of subplatysmal fat and soft tissue.
It is advisable to have patients return 2–3 weeks after a treatment ses­
sion with OnaBTX-A to assess their response to the treatment and
their satisfaction with the overall results. Touch-up injections always
can be done to correct any asymmetry or lack of a response along a
particular neck band or cord.65
Treatment with OnaBTX-A has been beneficial in preparing a
patient for submental liposuction because, by relaxing the neck bands,
Figure 15.79  Contracting the platysma makes grasping the skin and band easy to
inject OnaBTX-A into the lower dermis.

Botulinum Toxins in Clinical Aesthetic Practice
284
a more even draping of the anterior neck skin can be achieved in the
postoperative period after liposuction. In those patients in whom lipo­
suction surgery has unmasked vertical neck bands postoperatively,
injections of OnaBTX-A will help conceal them again after surgery.68
When there is a significant amount of fat herniation from in between
the two lateral sheets of platysma in certain patients, along with sub­
mandibular fat occupying the submental area, deoxycholic acid injec­
tions or liposuction with or without a platysmaplasty and possibly a
rhytidectomy, are the only treatments that will be corrective (Figure
15.81). Injections of OnaBTX-A in these patients are marginally help­
ful. On the other hand, when there is no herniation or protrusion
of subplatysmal fat and the presence of submental fat is negligible,
injections of OnaBTX-A will be effective in reducing the vertical neck
bands and cords created by a hypertrophic platysma (Figure 15.82).
In some authors’ experience, the anatomic type or configuration of
platysmal decussation (Figure 15.78b) does not necessarily prove to be
predictive of whether a treatment of OnaBTX-A will be successful.62 It
is the length of the platysma, the extent of muscle flaccidity, and the
degree of muscle hypertrophy that seem to be the predictive factors
that mostly influence the success rate of a treatment of OnaBTX-A in
the neck. In fact, flaccid neck bands that are heavy and loose can be
made worse with injections of OnaBTX-A (Figure 15.77).
In patients who experience suboptimal results with residual
banding and asymmetric draping of the anterior neck skin after
(a)
(b)
Figure 15.80  (a, b) Raising a wheal while injecting OnaBTX-A in the neck attests to the superficial placement of the product.
(a)
(b)
Figure 15.81  (a, b) The significant amount of fat in between bands of the neck of this 49-year-old may be more conducive to alternative treatment, i.e., liposuction.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
285
rhytidectomy, injections of OnaBTX-A can help normalize these
types of unwanted outcomes. The additional benefit of a slight ele­
vation of the lower lip and buccal commissures and a tightening of
lower cheek jowl has been known to occur.62,63,67 This effect of lower
face lifting takes place when OnaBTX-A diffuses from the fibers of
the upper platysma pars mandibularis into the decussating fibers of
the depressor anguli oris and the platysma (pars labialis), which are
immediately subjacent to the mandible during injections of platysmal
bands.62,63,67 This allows for compensatory muscle contractions by the
zygomaticus major, levator anguli oris, and risorius, contributing to a
“mini-chemical face lift.” This relaxation of the upper platysma (pars
mandibularis), along with a secondary tightening of the cerviofacial
angle62,63,67 was recently described as the Nefertiti lift.53
Complications (Adverse Sequelae) When Treating Horizontal
Lines and Vertical Bands of the Neck (see Appendix 6)
Treatment of horizontal rhytides and vertical bands in the neck with
OnaBTX-A usually is very safe, and there is a very low incidence of
untoward sequelae, provided the injections are place intradermally.
When complications do occur, however, they usually are the result of
improper technique and overzealous dosing.
Since the underlying nine muscles of deglutition, phonation,
and neck flexion are also cholinergic in origin, overdosing with
OnaBTX-A when treating the neck bands can result in xerostomia,
dysphagia, dysphonia, dysarthria, and neck weakness.62,69,70 The static
wrinkles caused by solar elastosis and age usually are not affected by
OnaBTX-A. Injections of more than 50 U of OnaBTX-A in the neck
increases the risk for temporary hoarseness and difficulty with swal­
lowing (dysphagia). Older patients are more at risk for such complica­
tions because they present with more wrinkling and banding of their
necks and commonly require higher doses of OnaBTX-A to achieve
satisfactory results. They also have a diminution in the soft tissue sup­
port of the neck, making it easier for the OnaBTX-A to diffuse to other
deeper muscles of the neck, which will affect deglutition, speech, and
the overall strength of the neck in keeping it upright, especially if
the sternocleidomastoid is weakened. Similar complications can be
produced in younger patients when OnaBTX-A is injected too deeply,
because it can affect the deeper musculature of the neck.
In patients treated for cervical dystonia in whom over 200 U of
OnaBTX-A commonly are injected into the strap muscles of the neck
during one treatment session, dysphagia, hoarseness, dry mouth, and
flu-like syndromes have been frequently observed.62,63,70–72
When OnaBTX-A is injected in the neck only to reduce platysmal
banding and transverse rhytides, mild and transient neck discomfort
can occur 2–5 days after treatment, with only a rare occurrence of
neck weakness experienced with head elevation and flexion.62 Only 1
patient out of 1500 in a multiple center treatment study experienced
clinically significant dysphagia, which resolved spontaneously within 2
weeks. Profound dysphasia was reported in 1 patient when more than
75–100 U of OnaBTX-A were used to treat platysmal bands during one
treatment session.73 A nasogastric tube was temporarily required to feed
the patient until she could swallow without assistance.
Commonly observed and expected side effects include transient
edema and erythema, both of which usually resolve within 1–2
days. Postinjection ecchymoses may last a few days longer. Other
less commonly occurring adverse sequelae can include muscle sore­
ness or neck discomfort and mild headache. A few patients complain
of either difficulty or, in extreme cases, an inability to lift the head
from the supine position and then to keep it still, steady, and upright.
When OnaBTX-A injections are placed less than 1–2 cm beneath the
menton at the inferior margin of the mandible, centrally, fibers of the
depressor labii inferioris can be weakened by spread of the product.
This can cause a reduction in the strength of the lower lip and the
integrity of perioral sphincteric balance (Figure 15.73). For many
patients, the cost–benefit ratio is not significant enough to make this
procedure a regularly sought-after treatment.
Figures 15.83 through 15.86 are additional examples of different
patients treated with OnaBTX-A for horizontal lines and vertical
bands of the neck.
Treatment Implications When Injecting the Neck

1. Superficial intradermal injections of OnaBTX-A can diminish
horizontal wrinkles and vertical bands of the neck.

2. The platysma lies superficial to the muscles of deglutition
and neck flexion while deep injections of large amounts of
OnaBTX-A too low down the neck can weaken these muscles
and cause varying degrees of dysphonia, dysphagia, and an
inability to raise the head and keep it steady and upright.
Injections should not go below the level of the thyroid
cartilage.
(a)
(b)
Figure 15.82  A 52-year-old patient is seen (a) before and (b) 3 weeks after treatment with OnaBTX-A.

Botulinum Toxins in Clinical Aesthetic Practice
286

3. Injecting the platysma pars mandibularis can affect the corners
of the mouth, lower lip, chin, and inferior border of the mandible
because of the interdigitation of platysmal fibers into the mimetic
muscles of the lower face. Therefore, injections of onaBTX-A
should start at least 1.5–2 cm below the mandibular border.

4. In older patients with lax, redundant skin and attenuated pla­
tysma fibers that are separated and form flaccid neck bands
and cords, so-called “turkey neck deformity”, injections of
OnaBTX-A may enhance rather than diminish the appearance
of those neck bands.

5. Injections of OnaBTX-A cannot correct the herniation of sub­
platysmal fat or reduce the fullness of excessive amounts of
submental or submandibular fat.

6. Injections of OnaBTX-A should be applied at least 1.5–2.0 cm
inferior to the mandibular origin of the depressor labii inferi­
oris to prevent distortions of the skin of the chin and dysfunc­
tion of the lower lip.

7. Horizontal neck lines do not always completely efface with
injections of OnaBTX-A, especially in an older person with
lipodystrophy, and excessively lax and severely photodam­
aged skin.
UPPER CHEST AND DECOLLETE WRINKLING
Introduction: Problem Assessment and Patient Selection
When the fashion of women’s clothing becomes more revealing,
the décolleté takes on an entirely new significance, revealing the
tell-tale skin surface changes caused by the innumerable number
of hours one has spent in the sun, either at leisure or for work.
Inelastic, sagging facial and neck skin that has been rejuvenated to
a more youthful appearance by myorelaxation redraping and resur­
facing techniques and with soft tissue fillers and implants will be
marred by the appearance of the crepe paper-like wrinkling of the
“V” of the upper chest. On the upper chest, both static and dynamic
wrinkling can coexist. When they do, the person exhibiting them
(a)
2
2
2
2
2
2
(b)
Figure 15.83  A 71-year-old patient is seen (a) before and (b) 3 weeks after treatment with OnaBTX-A.
(a)
(b)
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Figure 15.84  This 52-year-old patient (the same patient as in Figure 15.80) is seen (a) before and (b) 2 months after treatment with OnaBTX-A. Note the additional attenu­
ation of the horizontal wrinkles.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
287
appears deceptively older than their stated age, spoiling the youth­
ful impression that is portrayed by a supple and wrinkle-free
face and neck. Recently, superficial and middepth wrinkles on
the upper anterior chest wall have been successfully treated with
OnaBTX-A.19,74,78
There also have been reports describing the use of OnaBTX-A to
relax postsurgical myospasm of the fibers of the pectoralis complex
after breast implantation surgery.75,76 Subsequently, there appeared a
report describing the use of injections of AboBTX-A to reduce wrin­
kles of the lower anterior neck and upper chest wall attributed to the
excessive contractions of the platysma.76
Functional Anatomy of Upper Chest and Decollete Wrinkling
(see Appendix 2)
The platysma is composed of two separate paired broad, flat, thin
sheets of muscle originating from the superficial fascia of the upper
part of the thorax over the pectoralis major and deltoid, extending
over the full length of the neck. In certain patients, the platysma can
originate lower than the second, and as far down as the fourth to the
sixth intercostal space (Figure 15.67). The platysma can vary con­
siderably in thickness and extent; in general, women have a thinner
platysma than men.51 However, in some women when a large, thick
and extensive platysma is in constant, hyperkinetic contraction,
(a)
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
(b)
Figure 15.85  This 66-year-old patient is seen (a) before and (b) 2 weeks after treatment with OnaBTX-A. Note the dimpling of the mentalis, because it was mentalis was
not treated in this patient.
(a)
2
2
2
2
2
2
(b)
Figure 15.86  A 47-year-old patient (a) before and (b) 1 month after treatment of the platysmal bands with OnaBTX-A. The mentalis, depressor anguli oris, and perioral
rhytides were also treated with OnaBTX-A.

Botulinum Toxins in Clinical Aesthetic Practice
288
excessive horizontal and vertical wrinkling in the center of the
chest, from mid to the lower décolleté can occur75 (Figure 15.87).
These changes are more commonly seen in individuals who have
spent the better part of their daily activities and leisure time out­
doors in low cut, revealing clothing.
Dilution When Treating Upper Chest and Decollete Wrinkling
(see Appendix 3)
Because of the large surface area of the upper chest, a more exten­
sive coverage of OnaBTX-A is necessary and widespread diffusion is
encouraged. Therefore, a 100 U vial of OnaBTX-A can be reconsti­
tuted with 2–4 mL of normal saline.
Dosing: How to Correct the Problem (see Appendix 4), (What to
Do and What Not to Do) When Treating Upper Chest and
Decollete Wrinkling
The patient can be treated more comfortably in the semireclined
rather than in the upright position. OnaBTX-A can be injected into
each site on the anterior chest wall in several different treatment pat­
terns. The key to a successful outcome is to have the OnaBTX-A dif­
fuse throughout the entire anterior expanse of the upper chest wall.75
Injections should be applied superficially into the deep dermis or at
the dermosubcutaneous junction, particularly because the soft tissue
density of the chest is relatively thin. Intercostal muscle injection with
OnaBTX-A must be avoided; otherwise, the patient may have severe
difficulty with deep respirations. The pattern of injection depends
on the particular shape of an individual’s upper chest. Accordingly,
the area to be treated is outlined as either an upside down isosceles
or equilateral triangle, whose apex is at a point over the middle of
the xiphoid process of the sternum and whose base is an imaginary
line that connects two points placed over the middle of both clavicles
(Figure 15.88).74 This triangle corresponds to the points of interdigi­
tation of the clavicular portion and the sternocostal portion of the
platysma and pectoralis major. Approximately 2–4 U of OnaBTX-A
are injected into the dermosubcutaneous plane at multiple sites that
are roughly 1.5–2.0 cm apart from each other within the triangle. The
total dose injected should range from 20 to 50 U (average is 35 U) of
OnaBTX-A, depending on the overall strength of the platysma, the
number and depth of the wrinkling, and the size and expanse of
the anterior chest wall of the patient being treated. Some chests will
require anywhere from 6 to 12 injection sites to be successfully treated.
Gentle massage and point pressure with ice to the area injected can
prevent postinjection bleeding and ecchymoses. Severly photodam­
aged chest wall skin also needs to be treated by fractionated nonabla­
tive laser, light and energy-based devices that are readily available for
such situations to assure the long-term success of BoNT-A treatments.
(a)
(b)
Figure 15.87  (a, b) Area of the central upper chest with extensive vertical and some horizontal wrinkling.
(a)
(b)
Figure 15.88  (a) An upside-down triangle represents the area where the OnaBTX-A can be injected to reduce wrinkling. (b) Note fine wrinkling on chest in close-up.

15.  cosmetic uses of botulinum toxin a in the lower face, neck, and upper chest
289
Outcomes (Results) When Treating Upper Chest and Decollete
Wrinkling (see Appendix 5)
A smoothening of the surface of the mid to lower décolleté usually
occurs within 1–3 weeks after a treatment session of OnaBTX-A
(Figures 15.89 through 15.91).
The diminution of chest wrinkling usually commences more
slowly than when OnaBTX-A is injected in the face, and it may be
effective for only 2–3 months (Figures 15.89 and 15.92). Widespread
diffusion of the injected OnaBTX-A is necessary to achieve total cov­
erage and complete reduction in the wrinkling of the skin surface
of the upper chest wall. Therefore, injections in the upper chest wall
are performed preferably with high volumes of low concentrations
of OnaBTX-A.38 For many patients with severely photodamaged skin
of the upper chest wall, a combination of treatments with soft tissue
fillers, laser, light and energy-based devices, and daily application of
collagen enhancing cosmeceuticals along with regular OnaBTX-A
injections is the only way to recapture a youthful decollete.
Complications (Adverse Sequelae) When Treating Upper Chest
and Decollete Wrinkling (see Appendix 6)
The most common side effect reported when treating the decollete with
OnaBTX-A is inadequate clinical results because of insufficient dosing.
Additional adverse sequelae include a reduction in upper extremity
muscle strength, especially on adduction and internal rotation as when
performing a hugging motion. If OnaBTX-A is injected too deeply and
at higher doses, exceeding 75–100 U per treatment session, unintended
weakening of the intercostal musculature can occur, which may inter­
fere with deep respiration. This absolutely needs to be avoided in both
young patients who are physically active in sports and during routine
daily activities, and in older patients who may already suffer from some
sort of respiratory compromise.
The clinical results of pectoral platysma weakening can take up to
15 days or longer to occur, a much slower onset of effect compared to
that which occurs after OnaBTX-A injections of facial muscles.76,77
The more severely photodamaged the skin of the chest, the more
readily bruising occurs with the injections of OnaBTX-A no matter
how carefully the treatements are performed. The other frustrating
adverse result is the quantity and the cost of so much OnaBTX-A
that often produces so little appreciable changes. Therefore, for many,
the cost–benefit ratio is not an incentive to have this procedure per­
formed on a regular basis.77
Treatment Implications When Injecting the Upper Chest

1. Injections of high-volume, low concentration OnaBTX-A in the
upper “V” of the anterior chest wall can suppress the fine sur­
face wrinkling of the skin of the decollete.
(a)
(b)
Figure 15.89  (a) Asterisks represent points where 5 U of OnaBTX-A were injected; (b) post-treatment. (Courtesy of Dr. Francisco Perez-Atamoros.)
(b)
(a)
4
4
4
4
4
4
4
4
4
4
Figure 15.90  (a) Area of the central upper chest of a 56-year-old treated with OnaBTX-A before and (b) 5 weeks after treatment. (Courtesy of Dr. Francisco Perez-Atamoros.)

Botulinum Toxins in Clinical Aesthetic Practice
290

2. Induction of effect after a treatment with OnaBTX-A in the upper
chest wall takes longer and lasts for a shorter amount of time com­
pared to OnaBTX-A injections in the face.

3. Overdosing OnaBTX-A can cause difficulty with deep inspira­
tion or with adducting the upper extremities, as is done when
one performs a hug.

4. Injections of OnaBTX-A must be performed intradermally to
prevent weakening of the intercostal musculature and difficulty
with deep inspiration.

5. For many individuals, the cost and questionable benefit of having
the upper chest treated with OnaBTX-A to diminish fine wrin­
kling is not conducive to frequent and regular treatments.

6. Combination treatments with fillers, laser, light and
energy-based devices along with OnaBTX-A is the only
way patients with severely photodamaged skin of the upper
chest will be able to realize a noticeable rejuvenation of the
decollete.

7. Injecting severely photodamaged skin of the upper chest can
cause easy bruising no matter how carefully and gently the
injections are performed.
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