Phẫu Thuật Tạo Hình (Tập 6): Bàn Tay Và Chi Trên – Neligan (Ấn bản 4)

57
Physical examination specific to the hand
A
Radius
Push
Loosened deep dorsal radioulnar ligament
Taut deep palmar radioulnar ligament
Ulna
B
Radius
Push
Loosened deep palmar radioulnar ligament
Taut deep dorsal radioulnar ligament
Ulna
Fig. 2.8  Distal radioulnar joint (DRUJ) instability test. (A) Examination for the palmar instability of the DRUJ. The examiner pushes the ulna head from the palmar side
when the forearm is pronated to examine the deep palmar distal RU ligament. The deep palmar ligament is taut in the forearm pronated. (B) Examination for the dorsal
instability of the DRUJ. The examiner pushes the ulna head from the dorsal side when the forearm is supinated to examine the deep dorsal distal RU ligament. The deep
dorsal ligament is taut in the forearm supinated.
ulnar wrist pain and a click or pop may be felt when the
examiner’s thumb is placed on the ulnocarpal joint (Fig. 2.9).12
The ulnar fovea sign
Purpose: To evaluate the foveal disruption of the distal radio­
ulnar ligaments and ulnotriquetral ligament injuries.
Maneuver: The ulnar fovea is a dynamic nucleus of the ulnar
wrist. The ulnar collateral ligament complex composed of the
deep layer of the radioulnar ligament, the ulnotriquetral liga­
ment, the ulnolunate ligament, and the ulnocapitate ligament
attaches to the ulnar fovea. The patient sits opposite the
examiner with the patient’s elbow on the table. The examiner
supports the patient’s hand to keep the elbow in 90° to 110°
of flexion, forearm in neutral rotation, and wrist in neutral
position with the patient’s upper limb relaxed. The examiner’s
thumb tip is then pressed distally and deep into the interval
“soft spot” between the ulnar styloid process, flexor carpi
ulnaris tendon, volar surface of the ulnar head, and the pisi­
form. The ulnar fovea sign is positive when there is exquisite
tenderness compared with the contralateral side. The positive
ulnar fovea sign supports the foveal disruption of the distal
radioulnar ligaments and ulnotriquetral ligament injuries
(Fig. 2.10).13
Pisiform gliding test
Purpose: To evaluate arthritis in the pisotriquetral joint.
Maneuver: The examiner palpates the pisiform and pushes it
down against the triquetrum and applies shear force between
the two bones. If there is arthritis in the pisotriquetral joint,
the patient will feel pain in the joint during this maneuver
(Fig. 2.11).
Midcarpal instability test
Purpose: To evaluate midcarpal stability.
Maneuver: The examiner places a thumb on the dorsal mid­
carpal joint and holds the patient’s affected hand with the
remaining four fingers. The patient’s forearm is stabilized
by the examiner’s opposite hand. A patient with midcarpal
instability will complain of pain in the midcarpal joint when
the wrist is deviated ulnarly or radially. Patients with dorsal
intercalary segmental instability (DISI) often complain of pain

58
SECTION I
CHAPTER 2 • Examination of the upper extremity
Supination
Ulnar deviation and axial loading
Fig. 2.9  Ulnocarpal abutment test. The wrist is subjected to
ulnar deviation and axial forces with the forearm fully
supinated or pronated.
Pronation
Ulnar deviation and axial loading
Fig. 2.10  The ulnar fovea sign. The tenderness over the ulnar fovea (positive ulnar fovea sign) strongly supports the foveal disruption of the TFCC. DPL, deep palmar
ligament; UCLC, Ulnocarpal ligamentous complex; UT, ulnotriquetral ligament.
Tear
Push
Fovea
Ulna
Radius
DPL
UTL
UCLC
Lunate
Triquetum
B
A

59
Physical examination specific to the hand
nerves should be considered. The Martin–Gruber connection
is an abnormal innervation of the median nerve to the motor
branch of the ulnar nerve. Patients with cubital tunnel syn­
drome and this nerve connection may have a sensory palsy
of the ulnar nerve without motor palsy.
Comprehensive sensibility evaluation includes static and
dynamic two-point discrimination (2PD) testing, Semmes–
Weinstein monofilament testing, vibrotactile threshold testing,
and cold-heat testing. The 2PD test evaluates the tactile
sensation of the skin and assesses density of the perception
receptors in the skin. Stimuli generated by the static 2PD test
are mainly sensed by Merkel cells (slow-adapting mechano­
receptors), while the main receptors of stimuli generated by
the moving 2PD test are Meissner corpuscles (quick-adapting
receptors). In the static 2PD test, a caliper is applied longitu­
dinally to the digit and the smallest distance between the tips
of the caliper that the patient can distinguish is measured. The
moving 2PD test is the smallest perceived distance between
the tips of a caliper that is moved longitudinally along the
ulnar or radial aspect of the finger.15 The normal distance is
3 mm for the moving 2PD test and 6 mm for the static 2PD
test of the fingertips. The Semmes–Weinstein test evaluates
the pressure perception of the skin of the fingers and assesses
the threshold of the perception receptors in the skin. This test
is conducted by touching the fingers with filaments of various
diameters.15 The vibrotactile test also assesses the threshold of
the perception receptors and is performed using two types of
tuning forks with 30 cycles per second (cps) and 250 cps. The
vibrating forks are touched on the area examined and whether
patients can recognize the vibration is examined. Main recep­
tors of stimuli generated by the tuning forks with 250 cps are
Pacinian corpuscles, while those by the forks with 30 cps are
Meissner corpuscles. In the cold–heat test, the perception of
heat is evaluated by touching the skin with a test tube contain­
ing water at 40–45°C and the perception of cold is tested using
a test tube containing water at 10°C. Stimuli of the cold–heat
test are mainly sensed by free nerve endings of the skin
(Table 2.2).
in the ulnodorsal portion of the midcarpal joint, and a click
or pop may be felt when the wrist is deviated ulnarly.
Extensor carpi ulnaris synergy test
Extensor carpi ulnaris (ECU) tendinitis is a cause of ulnar-
sided wrist pain. The ECU synergy test is a provocative test,
indicating ECU tendinitis, which is often hard to distinguish
from TFCC injuries.
Purpose: To detect ECU tendinitis.
Maneuver: The patient’s forearm is held fully supinated. The
examiner asks the patient to abduct all fingers and applies a
counterforce to the index and small fingers sufficient to
prevent abduction of the index and small fingers. A patient
with ECU tendinitis will experience pain in the sixth extensor
compartment (Fig. 2.12).14
Assessment of peripheral nerves
Evaluation of peripheral nerves should include both motor
and sensory function.
To evaluate the motor function of the hand, it is necessary
to understand not only the anatomy and biomechanics of the
muscles of the upper extremity but also the peripheral inner­
vation of the muscles. An understanding of the order in which
branches of the nerves innervate muscles is important for
assessing nerve recovery after a nerve injury or a compression
neuropathy.
Sensibility testing also relies on knowledge of peripheral
nerve anatomy. It is essential to understand which parts of the
hand are innervated by which peripheral nerves. Peripheral
nerve palsy should be diagnosed using motor and sensory
evaluation. When the outcome of a motor assessment does not
coincide with that of a sensory assessment, abnormal innerva­
tion of muscles or an unusual connection between peripheral
Fig. 2.11  Pisiform gliding test.
Fig. 2.12  Extensor carpi ulnaris synergy test. The patient is asked to abduct the
fingers with the forearm fully supinated. The examiner applies counterforce to the
index and little fingers.

60
SECTION I
CHAPTER 2 • Examination of the upper extremity
longus and (hyper)extends the thumb MP joint to stabilize it
(Jeanne’s sign). Such patients also flex the PIP joint and hyper­
extend the DIP joint of the index finger to compensate for
weakness of MP joint flexion of the index finger (Fig. 2.14).
Jeanne’s sign
Purpose: To assess motor function of the ulnar nerve.
Maneuver: When patients with ulnar nerve dysfunction
attempt a lateral or key pinch of the thumb, they hyperextend
the thumb MP joint, which locks it to compensate for the
lateral instability of the joint secondary to weakness of the
thumb adductors.
Signs and tests for peripheral nerves
Tinel’s sign
Purpose: To detect nerve regeneration.
Maneuver: When the examiner taps on a peripheral nerve
distal to a nerve injury such as a compression neuropathy or
a laceration, the patient will experience tingling that radiates
distally along the course of the nerve. This phenomenon is
called a Tinel’s sign. The most distal point of the pain indicates
the site at which axon sprouting has occurred. Peripheral
nerve recovery after a nerve injury can be assessed by observ­
ing the advancement of Tinel’s sign along the nerve (approxi­
mately 1 mm/day of advancement).
Phalen’s test
Purpose: This test is used as a provocative test specific to
carpal tunnel syndrome.
Maneuver: With the elbow in neutral position, the patient’s
wrist is held in maximum palmar flexion for up to 2 min. This
increases pressure on the carpal tunnel and provokes pares­
thesia in the area innervated by the median nerve in patients
with carpal tunnel syndrome (Fig. 2.13). Maximum extension
of the wrist also increases pressure on the carpal tunnel. This
is called the reverse Phalen’s test.
Froment’s test
Purpose: To assess motor function of the ulnar nerve.
Maneuver: The patient is asked to hold a piece of paper
between the ulnar tip of the thumb and the radial tip of the
index fingers. The examiner slowly pulls the paper away from
the patient while encouraging the patient to hold on to it.
Patients with normal strength of the first dorsal interosseous
and adductor pollicis muscles keep the IP joint of the thumb
extended. If the patient has weakness of thumb adduction
caused by ulnar nerve palsy, the patient attempts to hold the
paper by flexing the thumb IP joint using the flexor pollicis
Table 2.2  Specific sensory testing and main receptors
Test
Perception
Main receptor
Type of adaptation
Evaluation of innervation
Static 2PD
Tactile
Merkel cell
Slowly
Density
Moving 2PD
Tactile
Meissner corpuscle
Quickly
Density
Tune fork (250 cps)
Vibration
Pacinian corpuscle
Quickly
Threshold
Tune fork (30 cps)
Vibration
Meissner corpuscle
Quickly
Threshold
S–W test
Pressure
Merkel cell
Slowly
Threshold
cps, Cycles per second.
(Reproduced with permission from Bell-Krotosoki J, Tomancik E. The repeatability of testing with Semmes-Weinstein monofilaments. J Hand Surg. 1987;12A:155–161.)
Clinical tip
Ulnar nerve palsy occurring distal to the FDP muscle branches
demonstrates more severe claw deformity than that occurring
proximal to the branches. This is because the FDP tendons
continue to flex the ring and little fingers, which accentuates
the hyperextension of the MP joints and flexion of the PIP and
DIP joints.
Fig. 2.13  Phalen’s test.
Fig. 2.14  Froment’s sign. A patient with left ulnar nerve palsy attempts to hold the
paper by flexing the thumb IP joint using the flexor pollicis longus and
hyperextending the thumb MP joint to stabilize it. He also demonstrates flexion of
the PIP joint and hyperextension of the DIP joint of the index finger to compensate
for weakness of MP joint flexion of the finger (Jeanne’s sign).

61
Physical examination specific to the hand
The Pitres–Testut sign: This maneuver reveals the function of
the second and third interosseous muscles. The patient is
asked to place the hand flat on a table and then to stretch the
long finger upward (i.e., to hyperextend it) and to deviate it
radially and ulnarly.
The “crossed fingers” sign (Video 2.6
): The function of the
first palmar interosseous and the second dorsal interosseous
muscles is evaluated by this sign. The patient is asked to cross
a flexed long finger over the index finger or to cross a flexed
index finger over the long finger when the palm and the ring
and little fingers are placed flat on a table.
Tests for evaluating sensory nerve function
Two-point discrimination (2PD) test (Video 2.7
)
Purpose: To evaluate the tactile sensation of the skin and assess
density of the perception receptors of the skin.
Maneuver: In the static 2PD test, a caliper is applied longitu­
dinally to the digit and the smallest distance between the tips
of the caliper that the patient is able to distinguish is mea­
sured. In the dynamic 2PD test, the distance between the tips
of a caliper that is moved longitudinally along the ulnar or
radial aspect of the finger is measured.14 The normal distance
is 3 mm for the moving 2PD test and 6 mm for the static 2PD
test. Although it is known that the main receptors for the static
2PD test are Merkel cells (slow-adapting mechanoreceptors)
and those for the moving 2PD test are Meissner corpuscles
(quick-adapting mechanoreceptors), the results of the 2PD
test reflect the functions of multiple sensory receptors in the
skin. This test is best for evaluation of nerve lacerations.
Semmes–Weinstein monofilament test (Video 2.9
)
Purpose: To evaluate the pressure perception threshold of the
skin. Stimuli generated by this test are mainly sensed by
Merkel cells (slow-adapting mechanoreceptors).
Maneuver: Filaments of various diameters are used. The
patient places a finger on a table with the palm up and closes
his or her eyes. The tip of a filament is held vertically against
the skin of the finger and sufficient force is applied to bend
the filament before allowing it to return to the vertical posi­
tion. The filament should remain in contact with the skin
surface after the force is released. If the patient senses the
pressure applied by the filament, other filaments of decreas­
ing diameter are used until the patient no longer senses the
pressure. The size of the smallest-diameter filament that can
be sensed by the patient is recorded (Table 2.3).16
Wartenberg’s sign
Purpose: To assess the motor function of the ulnar nerve.
Maneuver: The patient is asked to keep the fingers adducted
with the MP, PIP, and DIP joints fully extended. If the patient
has motor dysfunction of the ulnar nerve, the small finger
deviates away from the ring finger because the third palmar
interosseous muscle does not function and the extensor digiti
minimi muscle abducts the small finger (Fig. 2.15).
Other signs associated with ulnar nerve palsy
Duchenne’s sign: If the FDP muscles are functioning and
the intrinsic muscles are paralyzed (low-level ulnar nerve
palsy), the ring and little fingers show hyperextension of the
MP joint and flexion of the PIP and DIP joints (claw finger
deformity).
André–Thomas sign: A conscious effort to extend the fingers
by tenodesing the extensor tendons with palmar flexion of the
wrist only increases the claw deformity.
Bouvier maneuver: When hyperextension of the MP joint of
the ring and little fingers is corrected, the flexion of the PIP
and DIP joints of the fingers is reduced.
Fig. 2.15  Wartenberg’s sign. A patient with left ulnar nerve palsy demonstrates
inability to perform adduction of the left little finger when he attempts to adduct all
fingers.
Table 2.3  Semmes–Weinstein test
Evaluator size
Pressure force (g)
Color
Interpretation
1.65–2.83
0.008–0.07
Green
Normal
3.32–3.61
0.16–0.4
Blue
Normal
3.84–4.31
0.6–2
Purple
Diminished light touch sensation
4.56–4.93
4–8
Red
Diminished protective sensation
5.07–6.45
10–180
Red
Loss of protective sensation
6.65
300
Red
Deep pressure sensation only
(Reproduced with permission from: Bell-Krotosoki J, Tomancik E. The repeatability of testing with Semmes–Weinstein monofilaments. J Hand Surg. 1987; 12A:155–161.)

62
SECTION I
CHAPTER 2 • Examination of the upper extremity
The Allen’s test (Videos 2.7–2.10
) is helpful for determin­
ing if there is an intact circulatory connection between the
radial and ulnar arteries in the hand. If there is an intact circula­
tory path between the two arteries, the hand may be nourished
by either of the arteries.17 This test is essential for assessing
the vascularity of the hand before harvesting radial or ulnar
forearm flaps. If both arteries are not patent, pedicled forearm
flap elevation may compromise the vascularity of the hand.
To assess the circulatory connection between the radial and
ulnar palmar digital arteries, the same maneuver is performed
at the base of the fingers and thumb (digital Allen’s test
[Video 2.11
]). If there is no circulatory connection between
the palmar digital arteries, pedicled island flap harvest should
be avoided.
Allen’s test (Video 2.10
)
Purpose: To assess the blood supply of the radial and ulnar
arteries to the hand.
Maneuver: The patient places the dorsum of the hand on a
table. The examiner compresses the patient’s radial and ulnar
arteries at the wrist to occlude both arteries. The patient is
then asked to make and release a tight fist repeatedly to
exsanguinate the hand, after which the fingers are held in a
relaxed position. The examiner releases the pressure on the
radial artery while keeping pressure on the ulnar artery. The
time taken for blood to return to the hand and fingers is
noted. A normal interval for this process is 2–5 seconds. The
procedure is repeated for the ulnar artery.18
Digital Allen’s test (Video 2.11
)
Purpose: To assess the blood supply of the radial and ulnar
palmar digital arteries to the finger.
Maneuver: The patient is asked to place the dorsum of the
finger to be tested flat on a table. The examiner compresses
the ulnar and radial side of the patient’s fingertip with his or
her two fingers and moves them proximally to exsanguinate
the finger to be tested. The examiner then releases the pres­
sure on the radial palmar digital artery while maintaining
pressure on the ulnar digital artery.
The time taken for blood to return to the finger is noted. A
normal interval for this process is ≤3 seconds. The procedure
is repeated for the palmar ulnar digital artery of the finger. A
delay in the return of blood to the finger indicates that the
blood flow of the radial or ulnar palmar digital arteries is
impaired.
Physical examination specific to
the forearm
The main functions of the forearm are to transmit force
between the elbow and hand and to enable pronation and
supination. According to a cadaveric study, 80% of an axial
load applied to the wrist is transmitted to the radius and 20%
is transmitted to the ulna. The axial force is distributed to
the radiocapitellar and ulnohumeral joints in a 60 : 40 ratio,
respectively. Some 20% of an axial force applied to the radius
is therefore transferred to the ulna through the interosseous
membrane (IOM).19 After resection of the radial head, 90% of
an axial load applied to the forearm is transferred through the
IOM.20
Moberg’s pick-up test
Purpose: To generally evaluate the motor and sensory function
of the hand. This test is applied to patients with median nerve
injuries or injuries of both the ulnar and median nerves.
Maneuver: Small items such as a button, a key, and a paperclip
are placed on a cloth mat. The patient is asked to pick up each
item and put it into a small box as quickly as possible with
their eyes open and again with their eyes closed. The times
required to finish these tasks are measured (Fig. 2.16).17
Assessment of the vascular system
There are two types of vascular problems: arterial and venous
insufficiency. Vascular problems are assessed according to the
color, capillary refill, pressure (turgor) and temperature of the
affected part.
Arterial interruption causes a pale white or grayish discol­
oration of the affected area. Venous blockage results in blood
congestion, which causes a purple–blue discoloration.
Capillary refill is indicative of the circulation status of the
digits. When the fingertip or nail bed is depressed, the area
under pressure turns white. When the pressure is released,
the area should turn pink within 2 seconds. A delay in refill
is indicative of an arterial inflow problem. Prompt refilling
may indicate venous congestion. A decrease in skin pressure
or temperature may also indicate vascular problems.
Clinical tip
Touching the tip of the filament on the skin should be so
gentle that patients cannot recognize the touch of the filament
tip on the skin. Patients have to recognize the bending
pressure produced by the filaments. Some patients
misunderstand that the test is whether they recognize the
initial touch sensation of the filaments or not.
Fig. 2.16  Moberg pick-up test. A patient with eyes open or closed picks up small
items on a cloth mat and puts them into the box. The time required to finish the
task is recorded.

63
Physical examinations specific to the elbow
position. The length of the DOAC shortens as the forearm is
rotated from pronation to supination.
Measurement of forearm rotation
The patient should be seated on a chair with the elbow joints
tucked in lateral to the abdomen. The patient is asked to grasp
a pen in each hand and to rotate the forearm. The angle
between the pen and a line perpendicular to the floor should
be measured.
Measurement of the muscle strength
of the forearm
Supination
The main supinators of the forearm are the supinator muscle
and the biceps brachii muscle. The extensor carpi radialis
longus (ECRL) and brachioradialis (BR) muscles act as the
forearm supinators when the forearm is pronated.
Pronation
The main pronators are the pronator teres and pronator
quadratus (PQ) muscles. The flexor carpi radialis and palmaris
longus muscles also act as forearm pronators. The BR muscle
is a forearm pronator when the forearm is in the supinated
position. A recent study revealed that the PQ is responsible
for 20% of forearm pronation, except when in the fully pro­
nated position.24 The muscle power of the PQ should be
measured when the elbow joint is fully flexed to eliminate the
effects of the other pronators.
Pronation or supination strength is evaluated with the
elbow joint at 90° of flexion. Pronation strength is measured
by grasping the wrist with the forearm in a neutral or supina­
tion position. To test supination strength, the forearm should
be in a neutral or pronation position.
Physical examinations specific to
the elbow
Bony landmarks of the elbow
The medial epicondyle, lateral epicondyle and the tip of the
olecranon are located along a straight line (Hüter’s line) when
the elbow is extended and form an equilateral triangle (Hüter’s
triangle) when the elbow is flexed (Fig. 2.18). This feature is
helpful for identifying a deformity of the distal humerus
and elbow joint caused by fracture, malunion, dislocation or
growth disturbances.
On the lateral aspect, the capitellum of the humerus and
the radial head are easily palpable. The extensor muscles
originate from the lateral epicondyle. The radial nerve is
palpable in the interface between the BR muscle and the
brachialis muscle.
On the anterior aspect, the cubital fossa is bordered by the
BR muscle laterally and the pronator teres muscle medially.
The musculocutaneous nerve is located deep to the brachio­
radialis muscle and medial to the biceps brachii tendon. The
pulsation of the brachial artery is palpable, as it lies medial to
the biceps brachii tendon and deep to the lacertus fibrosus.
The interosseous membrane of
the forearm (IOM)
The IOM is divided into three portions. Each portion contains
several fibers that connect the radius and the ulna (Fig. 2.17).21
Distal membranous portion
Dorsal oblique band (DOB): This band functions as a stabilizer
of the DRUJ, in particular by restricting a palmar shift of the
ulna in the supination position.22
Middle ligamentous portion
a. Central band (CB): This is the strongest fiber of the IOM
and extends from the proximal radius to the distal ulna.
When the radial head removed, the CB carries 71% of the
overall mechanical stiffness of the forearm.20
b. Distal ligament of accessory band (DLAB)
c. Proximal ligament of accessory band (PLAB)
Proximal membranous portion
a. Distal oblique accessory cord (DOAC)
b. Proximal oblique cord (POC): a stabilizer of the proximal
radioulnar joint
Among these fibers, the DOB and CB are isometric compo­
nents and their lengths do not change during forearm rota­
tion.23 By contrast, the POC is shorter when the forearm is in
a neutral or supination position than when it is in a pronation
Fig. 2.17  Interosseous membrane of the forearm. CB, Central band; (DL)AB, distal
ligament of accessory band; DOB, dorsal oblique band; (PL)AB, proximal ligament
of accessory band.
Ulna
Radius
Distal membranous portion
Middle ligamentous complex
Proximal membranous portion
DOB
AB
AB
CB
Dorsal oblique
accessory cord
Proximal oblique
cord

64
SECTION I
CHAPTER 2 • Examination of the upper extremity
The median nerve is located just medial to the brachial artery
under the lacertus fibrosus, which can cause median nerve
palsy (pronator teres syndrome).
In the medial aspect, the ulnar nerve groove is palpable
between the medial epicondyle and the ulna. The ulnar nerve
is sometimes palpated as a strand in the posterior aspect of
the groove. In some patients with ulnar nerve palsy, a dislo­
cated ulnar nerve is palpable over the epicondyle when the
elbow is flexed.
On the posterior aspect, the olecranon and olecranon fossa
of the humerus are easily palpated. The triceps brachii tendon
is attached to the olecranon.
Ligaments of the elbow
Lateral ligament complex
The lateral ligament complex consists of the following four
ligaments (Fig. 2.19).
Fig. 2.18  Bony landmarks of the elbow. The medial (M)
epicondyle, (L) lateral epicondyle and the tip of the (O)
olecranon locate on a straight line when the elbow is extended
and form an equilateral triangle when the elbow is flexed.
M
M
L
L
O
O
Fig. 2.19  Lateral complex of the elbow.
Radial collateral
ligament
Lateral ulnar collateral
ligament
Accessory collateral
ligament
Annular ligament

65
Physical examinations specific to the elbow
more than the osteochondral articulation to restrain valgus
displacement when the joint is flexed. The osteochondral
articulation contributes more than the LCL to restrain varus
displacement, especially in the flexed position.
When examining instability of the elbow joint, the elbow
should be placed in a position in which other factors that
affect its stability (articulation and tension of the joint capsule)
are minimized. To assess collateral ligament integrity, the
elbow should be flexed by about 15°. This position relaxes the
anterior capsule and unlocks the olecranon from the fossa.
Varus instability of the elbow is therefore assessed with the
humerus in full internal rotation and varus stress is applied
to the slightly flexed joint. By contrast, valgus instability of
the elbow is evaluated with the humerus in full external rota­
tion while valgus stress is applied to the joint in slight flexion
(Fig. 2.21).25
Lateral ulnar collateral ligament
The lateral ulnar collateral ligament originates from the lateral
epicondyle, blends with the fibers of the annular ligament and
terminates at the tubercle of the crest of the supinator. It func­
tions as a primary stabilizer of the joint when a varus stress
is applied.
Radial collateral ligament
This structure originates from the lateral epicondyle and ter­
minates in the annular ligament. The ligament is located near
the axis of the elbow joint and is uniformly taut during elbow
motion.
Annular ligament
This ligament originates from the anterior margin of the
sigmoid notch and inserts on the posterior notch of the
sigmoid of the ulna to connect the radial head to the ulna.
Accessory collateral ligament
The ligament blends with the inferior margin of the annular
ligament to support the annular ligament during varus stress.
Medial collateral ligament complex
The medial collateral ligament complex consists of three por­
tions: the anterior bundle, the posterior bundle, and the
transverse ligament. The transverse ligament is not considered
functional. The posterior bundle is clinically insignificant with
regard to the stability of the elbow joint. Contracture of the
posterior bundle generates extension contracture of the elbow
joint. The anterior bundle functions as the prime stabilizer of
the elbow joint against valgus stress (Fig. 2.20).
Instability of the elbow joint
The elbow joint is stabilized by the medial collateral ligament
(MCL) complex, the lateral collateral ligament (LCL) complex,
the joint capsule, and the osteochondral articulation.
The MCL, joint capsule and osteochondral articulation
contribute equally to restrain valgus displacement of the
elbow joint when the joint is extended. The MCL contributes
Fig. 2.20  Medial complex of the elbow.
Anterior bundle
Posterior bundle
Transverse ligament
Clinical tip
Collateral ligament integrity of the elbow should be assessed
with the elbow in about 15° flexion, which relaxes the anterior
capsule and unlocks the olecranon from the fossa. Varus
instability of the elbow is assessed with the humerus in full
internal rotation and varus stress is applied to the slightly
flexed joint. Valgus instability of the elbow is evaluated with the
humerus in full external rotation while valgus stress is applied
to the joint in slight flexion.
Posterolateral rotatory instability
Insufficiency (loosening, rupture or laceration) of the lateral
ulnar collateral ligament causes posterolateral instability of
the elbow joint. Posterolateral rotatory instability (PLRI) is
evaluated using the pivot shift test maneuver.25
The pivot shift test
The patient is placed in a supine position with the shoulder
and elbow flexed at 90°. The examiner stands cephalad to the
patient. The examiner grasps the patient’s forearm in a fully
supinated position and extends the elbow slowly, applying
valgus and axial compressions to the joint. If the patient
has lateral collateral ligament insufficiency, these maneuvers
cause rotatory subluxation in the ulnohumeral joint. The
examiner continues to extend the elbow slowly. As the elbow
joint approaches extension, the radial head is suddenly dislo­
cated anteriorly. The prominence of the radial head disappears
and a skin dimple appears. The dislocated radial head is
repositioned by flexion of the elbow (Fig. 2.22).26
Measurement of malrotation of
the distal humerus
Patients in whom fractures of the distal humerus have not
been treated correctly often demonstrate malrotation of the
distal humerus, which restricts the functional arc of the shoul­
der joint. Malrotation of the distal humerus is easily assessed.
The patient is asked to stand and flex the trunk more than 90°
forward. The patient is then asked to extend both shoulder
joints maximally with the elbow joints in 90° of flexion.
The angles formed between the floor and the forearms

66
SECTION I
CHAPTER 2 • Examination of the upper extremity
A
Fig. 2.21  Assessment of the lateral instability of the elbow. (A) Varus instability of
the elbow is examined with the humerus in full internal rotation. (B) Valgus
instability is assessed with the humerus in full external rotation.
B
A
Valgus
Axial compression
Supination
Subluxation
Fig. 2.22  Pivotal shift test of the elbow. (A,B) Subluxation.
B
are measured. The malrotation angle of the affected distal
humerus can be measured by comparing it with that of the
contralateral normal side (Fig. 2.23).
Physical examination of thoracic
outlet syndrome
Thoracic outlet syndrome (TOS) is a broad term that refers
to compression of the neurovascular structures in the area
just above the first rib and behind the clavicle resulting in
upper extremity symptoms. It represents a constellation of
symptoms.
Classification
TOS is usually classified into two groups: neurogenic and
vascular. The neurogenic group is caused by compression
or irritation of the brachial plexus trunks and comprises

67
Physical examination of thoracic outlet syndrome
of the first rib inferiorly. This area may be small at rest and
may become even smaller in the posture with elevation or
hyperabduction of the upper limb, which moves the scapula
posteroinferiorly, resulting in the access of the clavicle to the
first rib. The anomalous structures, such as fibrous bands,
cervical ribs, and anomalous muscles, may constrict this space
further. The second space is the costoclavicular space, which
is bordered anteriorly by the middle third of the clavicle,
posteromedially by the first rib, and posterolaterally by the
upper border of the scapula. The last space is the subpectoralis
minor space beneath the coracoid process just deep to the
pectoralis minor tendon (Fig. 2.24).
Provocative maneuver
Adson test (Video 2.16 )
The patient is asked to inhale deeply with the chin up and tilt
the neck toward the involved arm holding the breath. If the
radial artery pulsation disappears or is diminished, the test is
positive. This test is considered sensitive to compression in
the interscalenus space (Fig. 2.25).28
The neck tilting
The patient is asked to inhale deeply and tilt the neck to the
opposite direction of the involved arm holding the breath. In
patients with TOS, this action produces arm heaviness, numb­
ness, and tingling in the fingers or/and arm, with some pain.
The costoclavicular compression test
The patient is asked to inhale deeply and hold the breath. The
examiner depresses the patient’s shoulder of the involved
limb. Patients with TOS complain of symptoms such as heavi­
ness, pain, numbness or tingling in the limb, and the pulsation
of the radial artery is often diminished. This maneuver calls
attention to compression in the costoclavicular space (Fig.
2.26).
Wright test
The examiner holds the patient’s arm in 90° abduction with
the elbow 90° flexed, and rotates the arm externally. If the
pulsation is diminished and the symptoms are provoked by
this maneuver, the test is positive. Entrapment of the neuro­
vascular bundle at the subpectoralis minor space or the cos­
toclavicular space can make the test positive (Fig. 2.27).29
Roos extended arm stress test (Video 2.17 )
The patient is asked to hold both arms with the shoulders in
90°-abduction and 90°-external rotation position and open
and close the hands repetitively. If the patient develops any
fatigue, pain, numbness or tingling in the hand or arm within
three minutes, the test is positive.30
Morley’s test
The patient complains of pain, numbness, tingling or uncom­
fortable feelings when the examiner pushes the patient’s
brachial plexus in the supraclavicular fossa.
These provocative tests should be performed on the bilat­
eral upper limbs and the outcomes of the involved limb
90% of the TOS. The neurogenic type can be divided into
three types, depending on involvement of cervical nerve
roots: the upper type (C5, C6, C7 spinal nerve involve­
ment), lower type (C8, T1 spinal nerve involvement), and
the combined type. The lower and combined types comprise
85–90% of all patients with TOS. Some 40–50% of TOS is
associated with distal compression neuropathies, such as
carpal tunnel, pronator teres, cubital tunnel, and radial tunnel
syndromes.24
The vascular group is subtyped into the venous type and
arterial type. The venous type comprises 70–80% of the vas­
cular group of TOS. The symptoms include pain, swelling,
distended vein, and discoloration of the affected upper limb.
Compression of the subclavian vein does not occur in the
interscalene space because it passes anterior to the anterior
scalene muscle, but usually occurs at the area between the
anterior scalene insertion to the first rib and at the costocora­
coid ligament and subclavius tendon insertion of the first rib.
This type sometimes develops into thrombosis formation in
the subclavian vein (Paget–Schroetter syndrome). The arterial
type comprises only 20–30% of the vascular group and occurs
with direct pressure of the cervical rib, or an abnormal middle
scalene muscle to the first rib, or anomalous band-like struc­
ture under the subclavian artery.27 Trauma to the neck, shoul­
der girdle, and upper extremity, particularly the lower trunk
and C8–T1 spinal nerves, is thought to play an important role
in developing the symptoms of thoracic outlet syndrome. The
trauma can be a single blow or a repetitive, strenuous type.27
Anatomy
The brachial plexus trunks and subclavian vessels are subject
to compression or irritation in three spaces at the thoracic
outlet region. The most important of these spaces is the inter­
scalene space (triangle), which is also the most proximal. This
space is bordered by the anterior scalene muscle anteriorly,
the middle scalene muscle posteriorly, and the medial surface
Fig. 2.23  Assessment of malrotation of the humerus. The patient is asked to stand
and flex the trunk more than 90° forward with the bilateral shoulder joints extended
maximally and the elbow joints in 90° of flexion. The angles formed between the
floor and the forearms are measured.

68
SECTION I
CHAPTER 2 • Examination of the upper extremity
observing the child’s activities when he or she is held by a
parent or is playing. Valuable information in terms of the
usage and dexterity of the upper extremity can be obtained
by observing children playing with age-appropriate toys or
props. The affected limb should be examined from the tip of
fingers to the hemithorax, which should be compared with
the contralateral limb to confirm the anomaly. The physical
examination should include not only a musculoskeletal
examination but also a nervous system examination. Primi­
tive reflexes, including the Moro reflex, the systemic tonic
neck response, the mouth lip reflex, and palmar grasp stimu­
lation are used to assess neuromuscular function in newborns.
As these patients age, gross movement patterns and integra­
tion of the affected hand into functional activities can be
assessed.
should be compared with those of the opposite one, because
the tests can be positive in a normal person.
Physical examination of the upper
extremity in children
Communication with very young children is often difficult or
impossible and young children are not able to articulate their
symptoms. A fatty subcutaneous tissue layer often prevents
doctors from identifying a deformity or swelling. It is often
difficult to locate the source of pain because children tend to
complain that the pain is everywhere. Questioning of the
parents and family of the patient is sometimes helpful for
making a diagnosis. Physical examination should include
Fig. 2.24  The three spaces that potentially entrap the neurovascular bundle in patients with the thoracic outlet syndrome.
Middle scalene
Long thoracic nerve
Anterior scalene
Phrenic nerve
1st rib
Costoclavicular space
Interscalene space
Subpectoral minor space

69
Physical examination of the upper extremity in children
Fig. 2.25  Adson test is sensitive to entrapment of the neurovascular bundle in the
interscalene space (arrows) by Adson test.
Fig. 2.26  The costoclavicular compression test is considered to detect the
entrapment in the costoclavicular space (arrow).
Fig. 2.27  The neurovascular bundle can be potentially entrapped in the
costoclavicular space (red arrow) and the subpectoralis minor space (black arrow)
by Wright test.

70
SECTION I
CHAPTER 2 • Examination of the upper extremity
3. Ranade AV, Rai R, Prabhu LV, et al. Incidence of extensor digitorum
brevis manus muscle. Hand (N Y). 2008;3:320–323. Small vestigial
extensor tendons are sometimes found in the long and ring fingers beside
the extensor digitorum communis tendons, which are called the extensor
digitorum brevis manus. This muscle is often found as a soft tissue mass
and sometimes causes pain in the dorsum of the hand.
7. Watson HK, Ryu J, Akelman E. Limited triscaphoid intercarpal
arthrodesis for rotatory subluxation of the scaphoid. J Bone Joint
Surg. 1968;68:245–349. Watson described his original maneuver of the
so-called “scaphoid test” in this article. This maneuver has been modified
by several authors and is now recognized as the “scaphoid shift test”,
which is a useful physiological examination to identify the instability of
the scapholunate ligament complex.
11. Kleinman WB. Stability of the distal radioulnar joint: biomechanics,
pathophysiology, physical diagnosis and restoration of function
what we have learned in 25 years. J Hand Surg Am. 2007;32A:1086–
1106. The author describes detailed anatomy and biomechanics of the
ulnar side of the wrist, including the TFCC. The deep layer of the distal
radioulnar ligament plays an important role to stabilize the distal
radioulnar joint. The dorsal deep layer of the ligament becomes tight in the
supinated forearm and the palmar deep layer increases the strain in the
pronated forearm.
20. Hotchkiss RN, An KN, Sowa DT, et al. An anatomic and mechanical
study of the interosseous membrane of the forearm:
pathomechanics of proximal migration of the radius. J Hand Surg
Am. 1989;14A:256–261. When the radial head was resected, 90% of the
axial load applied to the wrist joint was transmitted to the ulna through
the interosseous membrane. The central band of the interosseous
membrane provided 71% of the overall mechanical stiffness of
the forearm.
26. O’Driscoll SW, Bell DF, Morrey BF. Posterolateral rotatory instability
of the elbow. J Bone Joint Surg. 1991;73A:440–446. The authors
addressed grades of dislocation of the joint caused by lateral ligament
insufficiency (from instability of the joint to complete dislocation) and
described a maneuver of the pivot shift test that was provocative of the
elbow dislocation due to the lateral ligament instability.
Access the complete reference list online at

70.e1
References
References
1. Seddon HJ. Peripheral Nerve Injuries. Medical Research Council
Special Report Series. London: HMSO; 1954:282.
2. Tan JS, Oh L, Louis DS. Variations of the flexor digitorum
superficialis as determined by an expanded clinical examination.
J Hand Surg Am. 2009;34A:900–906.
3. Ranade AV, Rai R, Prabhu LV, et al. Incidence of extensor digitorum
brevis manus muscle. Hand (N Y). 2008;3:320–323. Small vestigial
extensor tendons are sometimes found in the long and ring fingers beside
the extensor digitorum communis tendons, which are called the extensor
digitorum brevis manus. This muscle is often found as a soft tissue mass
and sometimes causes pain in the dorsum of the hand.
4. Eaton RG. The extensor mechanism of the fingers. Bull Hosp Joint
Dis. 1969;30:39–47.
5. Harris C Jr, Riordan DC. Intrinsic contracture in the hand and its
surgical treatment. J Bone Joint Surg. 1954;36A:10–20.
6. Parkes A. The “lumbrical plus” finger. J Bone Joint Surg.
1971;53B:236–239.
7. Watson HK, Ryu J, Akelman E. Limited triscaphoid intercarpal
arthrodesis for rotatory subluxation of the scaphoid. J Bone Joint
Surg. 1968;68:245–349. Watson described his original maneuver of the
so-called “scaphoid test” in this article. This maneuver has been modified
by several authors and is now recognized as the “scaphoid shift test”,
which is a useful physiological examination to identify the instability of
the scapholunate ligament complex.
8. Yasuda M, Masada K, Takeuchi E. Dorsal wrist syndrome repair.
Hand Surg. 2004;9:45–48.
9. Reagan DS, Linscheid RL, Dobyns JH. Lunotriquetral sprains. J
Hand Surg Am. 1984;9A:502–514.
10. Kleinman WB. The lunotriquetral shuck test. Am Soc Surg Hand
Corr News. 1985;51.
11. Kleinman WB. Stability of the distal radioulnar joint: biomechanics,
pathophysiology, physical diagnosis and restoration of function
what we have learned in 25 years. J Hand Surg Am. 2007;32A:1086–
1106. The author describes detailed anatomy and biomechanics of the
ulnar side of the wrist, including the TFCC. The deep layer of the distal
radioulnar ligament plays an important role to stabilize the distal
radioulnar joint. The dorsal deep layer of the ligament becomes tight in the
supinated forearm and the palmar deep layer increases the strain in the
pronated forearm.
12. Tay SC, Tomita K, Berger RA. The “ulnar fovea sign” for defining
ulnar wrist pain: an analysis of sensitivity and specificity. J Hand
Surg Am. 2007;32A:438–444.
13. Tatebe M, Nishizuka T, Hirata H, Nakamura R. Ulnar shortening
osteotomy for ulnar-sided wrist pain. J Wrist Surg. 2014;3:77–84.
14. Ruland RT, Hogan CJ. The ECU synergy test: an aid to diagnose
ECU tendonitis. J Hand Surg Am. 2008;33A:1777–1782.
15. Dellon AL. The moving two-point discrimination test; Clinical
evaluation of the quickly-adapting fiber/receptor system. J Hand
Surg Am. 1978;3:474–481.
16. Bell-Krotosoki J, Tomancik E. The repeatability of testing with
Semmes-Weinstein monofilaments. J Hand Surg Am.
1987;12A:155–161.
17. Moberg E. Objective methods for determining the function value of
sensibility in the hand. J Bone Joint Surg. 1958;40B:476.
18. Allen EV. Thromboangitis obliterans: methods of diagnosis of
chronic occlusive arterial lesions distal to the wrist with illustrative
cases. Am J Med Sci. 1929;178:237–244.
19. Halls AA, Travill A. Transmission of pressures across the elbow
joint. Anat Rec. 1960;150:243–248.
20. Hotchkiss RN, An KN, Sowa DT, et al. An anatomic and mechanical
study of the interosseous membrane of the forearm:
pathomechanics of proximal migration of the radius. J Hand Surg
Am. 1989;14A:256–261. When the radial head was resected, 90% of the
axial load applied to the wrist joint was transmitted to the ulna through
the interosseous membrane. The central band of the interosseous
membrane provided 71% of the overall mechanical stiffness of the forearm.
21. Noda K, Goto A, Murase T, et al. Interosseous membrane of the
forearm: an anatomical study of ligament attachment locations.
J Hand Surg Am. 2009;34A:415–422.
22. Stuart PR, Berger RA, Linscheid RL, et al. The dorsopalmar stability
of the distal radioulnar joint. J Hand Surg Am. 2000;25A:689–699.
23. Moritomo H, Noda K, Goto A, et al. Interosseous membrane of the
forearm: length change of ligaments during forearm rotation.
J Hand Surg Am. 2009;34A:685–691.
24. McConkey MO, Schwab TD, Travlos A, et al. Quantification of
pronator quadratus contribution to isometric pronation torque of
the forearm. J Hand Surg Am. 2009;34A:1612–1617.
25. Morrey BF. The Elbow and its Disorders. 3rd ed. Philadelphia. US: WB
Saunders Company; 2000.
26. O’Driscoll SW, Bell DF, Morrey BF. Posterolateral rotatory instability
of the elbow. J Bone Joint Surg. 1991;73A:440–446. The authors
addressed grades of dislocation of the joint caused by lateral ligament
insufficiency (from instability of the joint to complete dislocation) and
described a maneuver of the pivot shift test that was provocative of the
elbow dislocation due to the lateral ligament instability.
27. Atasoy E. A Hand surgeon’s experience with thoracic outlet
compression syndrome. J Hand Surg Am. 2010;35A:1528–1538.
28. Adson AW. Surgical treatment for symptoms produced by cervical
ribs and the scalenus anticus muscle. Surg Gynecol Obstet.
1947;85:687–700.
29. Wright CJS. The neurovascular syndrome produced by
hyperabduction of the arms. Am Heart J. 1945;29:1–19.
30. Roos DB. New concepts of thoracic outlet syndrome that explain
etiology, symptoms, diagnosis, and treatment. Vasc Surg.
1979;13:313–321.

SECTION I • Introduction and Principles
3 
Diagnostic imaging of the hand and wrist
Alphonsus K.S. Chong, Jin Xi Lim, and David M.K. Tan
SYNOPSIS
■ Radiographs form the cornerstone of diagnostic imaging of the hand
and wrist, and are usually the first imaging modalities performed
following clinical evaluation.
■ The keys to obtaining the most information from radiographs are
ordering the correct radiographs for the situation, and ensuring the
radiograph is appropriately taken.
■ A systematic and careful examination of the radiograph is necessary to
glean the often subtle findings in the hand and wrist.
■ Clinical evaluation with plain radiographs often provides sufficient
information for clinical decision-making.
■ Computed tomography (CT) scans, ultrasound, magnetic resonance
imaging (MRI), and other advanced imaging modalities can
supplement information from plain radiographs in selected situations.
On occasion, they may be the primary imaging study performed.
■ These advanced imaging modalities allow today’s clinician to
visualize disorders that would previously have required open surgery
or biopsy.
Introduction
■ A proper and directed history-taking followed by a
careful examination of both hands and wrists forms the
foundation of making a clinical differential diagnosis in
hand conditions.
■ Appropriate investigations are then ordered to help
confirm the clinical diagnosis.
■ Diagnostic imaging modalities are often the first-line
investigations ordered, as many clinical conditions in the
hand and wrist can be seen visually.
■ Technological advances in many advanced imaging
modalities like ultrasound, CT, and MRI, have led to
them being applied for use in the hand and wrist. This
increases clinician choices for diagnostic imaging of a
suspected clinical condition.
■ The radiograph, despite its simplicity and age, still forms
the foundation of imaging of hand and wrist conditions.
In many clinical situations, an appropriately chosen and
well-taken set of radiographs may be all the diagnostic
imaging required.
■ The key to obtaining the most information from a
radiograph is to understand which radiographs are
appropriate for each clinical situation, and how to obtain
good-quality radiographs for evaluation.
■ Advanced imaging modalities may then be ordered to
provide additional information for decision-making.
■ This chapter will equip the reader with practical
information about the different imaging modalities
available for the hand and wrist.
■ It will start from the foundation of radiographs, covering
the appropriate views, how they are taken, and how best
to evaluate them. Following which, the advanced
imaging techniques will be described in turn,
emphasizing their applications in the hand and wrist.
Access the Historical Perspective section online at

Radiography
Radiography is the cornerstone in diagnostic imaging of the
hand and wrist. It should be the first imaging modality for
the diagnosis of most hand and wrist disorders.2 The plain
radiograph is inexpensive in relation to other imaging modali­
ties, technically easy to perform, and widely available. The
correct radiograph taken in an appropriate manner provides
much imaging information to the attending clinician. In many
hand and wrist conditions, radiography may also be the
only imaging modality required for definitive diagnosis and
assessment.
  Access video content for this chapter online at expertconsult.com

71.e1
Historical perspective
Historical perspective
The origins of diagnostic radiology are of particular signifi­
cance to hand surgery. The first radiograph of human anatomy
after the discovery of X-rays by Wilhelm Conrad Roentgen
was that of his wife’s hand in 1895. The medical community
was quick to see the potential applications of this technology,
and radiographs were rapidly adopted for clinical use. As a
result, Roentgen is considered the father of diagnostic radiol­
ogy, and his discovery led him to win the first Nobel Prize in
Physics in 1901.
Plain X-ray radiographs are still the first-line imaging
modality for the diagnosis of most hand and wrist disorders.
Plain film radiography has progressed from a tedious process
using an acetate-based film to one that applies digital technol­
ogy. In newer facilities, widespread adoption of digital tech­
nology has led to radiographs that are not printed on film, but
viewed on the computer screen. Beyond technology, the
development of special views through positioning of the
patient or machine, and stress application, has enabled
improvements in imaging of specific disorders. The develop­
ment of water-soluble contrast dyes allowed the use of X-rays
to perform arthrography.
CT, MRI, and ultrasound are advanced imaging technolo­
gies that have become widely adopted for musculoskeletal
imaging, including the hand and wrist. Improvements in
hardware technology, software, and imaging protocols have
resulted in improved imaging of bone, joints, and soft tissue.
These technologies have enabled detailed visualization and
assessment of the musculoskeletal system and its disorders in
a noninvasive manner. Prior to these technologies, many of
these disorders would have required open surgery or biopsy
for diagnosis.
Improvements in imaging modalities and technology are
only part of the equation for the advances made in musculo­
skeletal imaging. Equally important has been the parallel
development of musculoskeletal radiology as a distinct sub­
specialty.1 The dedication of musculoskeletal radiologists has
been instrumental in developing their field, and subspecialty
training of future musculoskeletal radiologists. These radiolo­
gists can better appreciate the often subtle findings on imaging,
leading to improved diagnosis. This has translated to earlier
and more effective clinical care and improved outcomes.
Musculoskeletal radiology continues to progress at a rapid
pace as both a clinical specialty and in technological advances.
Building on its strong foundations, musculoskeletal imaging
will continue to be a crucial pillar in the diagnosis and assess­
ment of hand and wrist disorders.

72
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
Fig. 3.1  The posteroanterior (PA) radiograph of the hand and wrist is taken in the
position shown. For the hand radiograph, the beam is centered over the midshaft of
the third metacarpal. For the wrist radiograph, it is centered over the capitate.
Incident beam of X-ray perpendicular
to the X-ray cassette
Beam direction and central position:
A Wrist PA – centered over capitate
B Hand PA – centered over 3rd metacarpal
midshaft
Shoulder abducted 90º
Elbow flexed 90º
Fig. 3.2  The oblique hand radiograph is taken with the hand positioned as shown.
This position provides a good non-overlapping view of the metacarpals. The view is
not adequate for assessment of the digits; separate lateral views of the digits should
be performed if necessary.
Incident beam of X-ray perpendicular
to the X-ray cassette and centered
over the third metacarpophalangeal joint
Forearm resting on table and
pronated, radius, and third
metacarpal collinear
Thumb and index fingertip brought close;
hand lies in 45º of pronation
Fig. 3.3  This female patient presented with a soft-tissue mass over the ulnar side
of the middle finger. The radiograph shows the outline of the soft-tissue mass with
scalloping of the ulnar border of the middle phalanx. Histology of the mass showed
this to be a pigmented villonodular synovitis.
Evaluation of the hand
The three basic radiographs to evaluate the hand are: postero­
anterior (PA), oblique, and true lateral views. The radiographs
should be performed in a standardized fashion to allow
proper evaluation (Figs. 3.1 & 3.2). Specialized views are
required to assess specific areas not well seen in the above
views. The PA hand view provides a useful overview of the
skeletal structure of the hand. Fractures, osseous tumors, and
even soft-tissue masses (Fig. 3.3) can be seen on this view. The
oblique view of the hand is useful to assess the metacarpals,
as a true lateral view of the hand will lead to an overlapping
of the second to fifth metacarpals. In the common boxer’s or
fifth metacarpal neck fracture, this view allows an assessment
of the amount of angulation of the fracture.
In hand radiographs, begin by assessing the overall align­
ment of the metacarpals and phalanges. The individual bones
should then be evaluated in terms of cortical shape and
integrity, as well as bony quality. Fractures are usually easy
to detect, although a careful review is necessary in the case
of undisplaced or minimally displaced fractures. Osseous
tumors are identified by an area of different lucency in the
bone. There may be changes in the outline of the bone.
Enchondromas are common benign bony tumors in the hand.
They can result in pathological fractures, so an assessment of
the bone for such pathology should be done, particularly if
the trauma resulting in the injury is trivial (Fig. 3.4). Osteo­
myelitis typically occurs in the hand following open injuries
(Fig. 3.5).
The joints should then be assessed, starting from the car­
pometacarpal joints (CMCJs) and working distally. The CMCJs
may be dislocated following injury. These injuries are uncom­
mon but are difficult to diagnose. In a normal hand X-ray the
second to fifth CMCJs should be clearly visible on the PA view
(Fig. 3.6).3 The loss of these features in the second to fifth
CMCJs is usually due to a fracture dislocation of one or more
of the CMCJs. However, an improperly performed hand
radiograph can also give this impression. Fisher et al. described
a systematic approach to evaluating the PA view of the hand
for dislocations of the fourth and fifth CMCJs.3 In subluxation
of the fifth CMCJ, the base of the fifth metacarpal is usually

73
Radiography
Fig. 3.4  This nurse presented with pain at the base of her right ring finger after
transferring a patient from his bed to a chair. The radiograph shows a partial
articular fracture of the base of the proximal phalanx of the right ring finger. The
area of lucency just at the fracture site and minor trauma were suspicious for a
pathological fracture.
Fig. 3.5  This elderly man presented with increasing pain and redness in the finger.
The radiograph shows a destructive lesion of the distal phalanx and head of the
middle phalanx. This is consistent with osteomyelitis. A differential diagnosis would
be that of a malignant bone tumor. These are much rarer, and usually due to
metastatic disease in terminally ill patients.
Fig. 3.6  In a normal hand radiograph, the second to fifth carpometacarpal joints
should be well visualized, as shown. The articular surfaces should be profiled
without overlap, parallel to each other, and have distinct cortical rims.
offset ulnarly compared to the hamate (Fig. 3.7). Several views
have been suggested to confirm this diagnosis. The true lateral
of the hand provides a useful way to assess the CMCJ for any
signs of dislocation and oblique views may also be helpful4,5;
if the diagnosis is still uncertain, a CT scan of the hand includ­
ing the CMCJs will confirm the diagnosis.6 The more distal
joints are then evaluated, from the metacarpophalangeal
joints to the proximal interphalangeal joints and distal inter­
phalangeal joints. A normal joint should be completely con­
gruent with a visible joint space.
Osteoarthritis commonly affects the interphalangeal joints
and thumb CMCJs. It is often demonstrable on radiographs
by narrowing of the joint space, subchondral sclerosis, osteo­
phytes, and deformity (Fig. 3.8).
Special views in the hand (Box 3.1)
A true lateral radiograph of the finger is needed to complete
an assessment of the digit. Hand radiographs alone are insuf­
ficient for assessment. This is because the oblique view of the
hand does not provide an adequate lateral profile of the digit
and interphalangeal joint spaces to supplement the PA view.
With only a PA view, subtle fractures, fracture displacement,
or joint subluxation of the fingers may not be apparent. Meta­
carpal head fractures may also be difficult to assess and the
Brewerton view7 will give additional information in addition
to the standard hand radiographs.
To assess the thumb, specialized views are also necessary
as the thumb lies in an oblique plane relative to the other
digits in the usual hand radiograph. A true PA and lateral
view of the thumb is obtained to allow proper radiographic

74
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
assessment of the thumb. One common condition in the
thumb for which radiographs are performed is that of basal
joint or trapeziometacarpal joint (TMCJ) arthritis (Fig. 3.9).
This condition is graded radiologically using the Eaton clas­
sification.8 The irregular saddle shape of the trapezium makes
visualization of the bone difficult, and the Betts view will
allow all four articulations of the trapezium to be visible
without overlap (Fig. 3.10).
The ulnar collateral ligament of the thumb metacarpopha­
langeal joint is commonly injured in forceful thumb abduc­
tion.9 Less commonly the radial collateral ligament may also
Fig. 3.7  This radiograph shows a dislocation of
the fifth carpometacarpal joint. Note the ulnar offset
of the fifth metacarpal with loss of the normal
articular space.
Fig. 3.8  Osteoarthritis of the distal interphalangeal joints of middle and ring
fingers. There is loss of joint space, and osteophytes are clearly seen on this lateral
view.
BOX 3.1  Special hand and thumb views
Brewerton view
Purpose: To obtain tangential views of the metacarpal heads – for
evaluation of metacarpal head fractures and erosive changes in
rheumatoid arthritis
Positioning: With the palm facing up, the MCPJs are flexed 65°
with the posterior aspect of the fingers in contact with the cassette,
and beam angled at 15° from the ulnar side of the hand
Betts/Gedda view
Purpose: To obtain a true lateral view of the TMCJ, and see the
trapezium in profile
Positioning: Palm of the hand must be placed flat on the
cassette with the hand and forearm pronated, with the beam is then
directed 5–10° distal to proximal
Robert’s view
Purpose: To obtain a true AP view of the TMCJ
Positioning: The hand and forearm is hyperpronated such that
the dorsum of the thumb lies on the cassette, with the beam angled
15° from the vertical

75
Radiography
Fig. 3.9  The trapeziometacarpal joint shows
narrowing of the joint space with osteophytes and
joint subluxation.
A
Fig. 3.10  (A) Hand radiograph showing a trapezium fracture. (B) The Bett’s view demonstrates the trapezial fracture and the step in the articular surface clearly.
B

76
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
A misdiagnosis rate of 8% for pediatric hand fractures was
found in one study.13 There are several reasons for this. Clini­
cal evaluation in children is more difficult, the more so the
younger the child. It may not be possible to localize the site
of the problem clearly, e.g., the site of injury following trauma.
Proper standardized views may also be difficult to obtain.
Other reasons for misdiagnosis include missing additional
fractures and using an X-ray that was obscured by dressings.13
When the clinical suspicion remains high and the films
obtained are inadequate, the radiograph should be repeated,
either the same day or at another time when the patient is
more cooperative. Similar views taken of the opposite unin­
jured limb are also helpful for evaluation.
Growth plate-related injuries are common in children.
These injuries can be classified according to the system
described by Salter and Harris (Fig. 3.12).14 The Salter–Harris
type II fracture injury is the most common type of growth
plate injury seen in the hand.
Wrist evaluation
A properly performed set of orthogonal wrist radiographs
forms the basis of an effective evaluation of the wrist.15,16 This
is especially important when indices are being measured. The
wrist has numerous asymmetrically arranged bones, so a
methodical assessment of the bones, joints, and overall align­
ment of the wrist is necessary.
be injured. Lateral stress application during the posteroante­
rior thumb radiograph can be helpful to assess if the ligament
injuries are complete or partial. Ultrasonography and MRI are
alternatives to assess this injury.10,11
Pediatric hand radiographs
Evaluation of the pediatric hand, especially after injury,
is often more difficult than in adults. All carpal bones
and epiphyses in the hand lack ossification in the newborn.
The ossification centers then appear in a well-recognized
sequence,12 as detailed in Table 3.1. The staggered ossification
of the various carpal bones (Fig. 3.11) and the presence of the
growth plate may confuse the examiner as to whether a
fracture is present or not.
Table 3.1  Appearance of ossification centers and fusion of epiphyses in children
Females
Males
Appearance of capitate and hamate
3 months
3 months
Appearance of distal radius ossification center
10 months
1 year 3 months
Appearance of phalanges and metacarpal ossification center
10 months to 2 years
14 months to 3 years
Fusion of phalangeal and metacarpal epiphyses
13–15 years
14–16 years
Fusion of distal radius and ulna epiphyses
15–17 years
17–19 years
Fig. 3.11  Commonest order of ossification: capitate, hamate, triquetrum, lunate,
scaphoid, trapezium, trapezoid, and pisiform. Note the position of the growth plates
on the proximal ends of the phalanges and first metacarpal. In the remaining ulnar
four metacarpals, the growth plate is on the distal end of the bone.
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Commonest order
of ossification:
Capitate
Hamate
Triquetrum
Lunate
Scaphoid
Trapezium
Trapezoid
Pisiform
Fig. 3.12  (A–E) The Salter–Harris classification of epiphyseal plate injuries.
(Redrawn after Salter RB, Harris R. Injuries involving the epiphyseal plate. J Bone
Joint Surg Am. 1963;45:587–621.)
Most common
Crush injury
of growth plate
A
D
E
B
C

77
Radiography
loss of this distance is seen in collapse of a carpal bone, for
example Kienbock’s disease (avascular necrosis (AVN) of the
lunate) or in malrotation of the carpal bones, for example in
rheumatoid arthritis or scapholunate (SL) dissociation. A ratio
is used instead of actual dimensions to correct for variability
in carpal bone sizes.
The ulnar variance provides a measure of the height differ­
ence between distal radius and ulnar articular surfaces. There
are several ways to measure the ulnar variance.21,22 We prefer
the technique of the perpendiculars (Fig. 3.17). It is easy to
perform and has been shown to have higher intra- and
interobserver reliability.23
Obtaining proper views for wrist radiographs (Figs. 3.1 &
3.13; see Fig. 3.18, below) requires careful positioning which
may be difficult to achieve in patients with pain or limitations
in motion of the affected upper limb (Box 3.2).
The wrist radiograph is first evaluated by checking the
overall alignment of the bones of the wrist, starting with the
distal radius and ulna, progressing to the carpal bones and
metacarpal bases. Gilula described three smooth arcs made by
the articular surfaces of the proximal and distal carpal row
bones in a normal wrist PA radiograph (Fig. 3.14).17 A loss of
the normal contour usually indicates a disruption in the
normal arrangement of these carpal bones. A common cause
of this is a perilunate dislocation (Fig. 3.15). Lunotriquetral
(LT) dissociation is another cause of the loss of the normal
Gilula’s lines. Care must be taken when interpreting these
findings in an asymptomatic patient as radial or ulnar devia­
tion of the wrist can introduce a break in the arcs.18
The overall relationship between the different bones can
also be assessed using two common parameters: the carpal
height ratio and ulnar variance. These provide a quantitative
assessment of the structural integrity of the carpal rows, and
the relationship of the distal radius and ulna articular surfaces,
respectively.
The carpal height ratio (Fig. 3.16)19,20 gives a measure of the
distance between the distal articular surface of the radius to
the proximal articular surface of the third metacarpal base. A
Fig. 3.13  Normal wrist radiograph. (A) In the posteroanterior view,
note the lateral position of the ulnar styloid and position of the
extensor carpi ulnaris groove. It lies radial to the straight line that
passes tangential to the radial edge of the ulnar styloid at the fovea.
This indicates a good posteroanterior view. (B) On the lateral view,
there is good radioulnar overlap.
A
B
BOX 3.2  Assessing quality of wrist radiographs
There are criteria for acceptable wrist views. The PA view is
assessed using the position of the ulnar styloid and extensor carpi
ulnaris tendon groove.15 The lateral view is assessed using the
radioulnar overlap and scaphopisocapitate relationships.16
Fig. 3.14  In a normal posteroanterior wrist radiograph, three smooth curved
non-overlapping lines can be drawn on the proximal and distal cortical surfaces of
the proximal carpal bones (lines 1 and 2) and proximal surface of the distal carpal
row (line 3). A disruption or step-off indicates a loss of the normal carpal bone
relationships.
3
2
1

78
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
radiograph of the contralateral normal wrist is helpful if the
findings are unclear. The application of volar or dorsal-
directed stress is also helpful in cases of suspected DRUJ
instability (Fig. 3.19).
Scaphoid fractures are the commonest carpal fracture. The
shape of the scaphoid bone does not lend itself well to evalu­
ation by just two orthogonal views, so a “scaphoid series” of
X-rays is usually done (Fig. 3.20 and Box 3.3).
Fractures of the hook of the hamate are uncommon but
disabling. A carpal tunnel view is helpful to diagnose this
injury (Fig. 3.21), although a CT scan can also provide the
definitive diagnosis.
Fig. 3.15  This radiograph shows a perilunate fracture dislocation with disruption of
the normal smooth carpal arcs. There are associated radioulnar shaft fractures.
Fig. 3.16  (1) Carpal height ratio = carpal height (L2)/third metacarpal length (L1).
Normal is 0.54 ± 0.03. (2) Revised carpal height ratio = carpal height (L2)/heights
of capitate (rL1). (3) Capitate–radius index (CR). This is the shortest line between
two eccentric arches of the carpal rows. The line is moved until the shortest
distance is measured. Mean CR index 0.999 ± 0.034. Values less than 0.92 are
abnormal.
L1
L2
rL1
CR
Fig. 3.17  Ulnar variance is measured on a true neutral posteroanterior view of the
wrist. First a line along the longitudinal axis of the radius is drawn. Next a line
perpendicular to this line through the volar ulnar sclerotic rim of the distal radius is
drawn. Finally a line parallel to this second line at the level of the distal cortical rim
of the ulna is drawn. The distance between these two parallel lines is the ulnar
variance.
Ulnar variance
Level of ulna
distal cortical rim
Longitudinal axis
of radius
Perpendicular to
axis through volar
ulnar sclerotic rim
line of distal radius
3
2
1
Fig. 3.18  A true lateral view of wrist is taken in the position shown.
Beam direction
X-ray cassette
Radius, wrist and
3rd metacarpal
collinear
Wrist neutral –
no palmar or
dorsiflexion
Elbow flexed 90º
A proper PA and lateral radiograph of the wrist (Fig. 3.18;
see Fig. 3.13) is the first necessary imaging for the evaluation
of a suspected distal radioulnar joint (DRUJ) instability.
Radiographic findings associated with this injury include
widening of the DRUJ, a fracture of the ulnar styloid base, or
a displaced fracture from the ulnar fovea. On the lateral view,
there is loss of the normal radioulnar overlap. A comparison
BOX 3.3  Scaphoid series
The scaphoid view of the wrist addresses the normal foreshortening
of the scaphoid seen on the conventional PA wrist radiograph. The
view is taken with the wrist ulnarly deviated and the X-ray tube
angled 20–30°. Several other views are helpful for assessment of the
scaphoid: a pronated oblique view (to view the distal third and
tubercle of the scaphoid better), a supinated view (to assess the
dorsoradial ridge of scaphoid and pisiotriquetral articulation), and a
lateral view to help assess a humpback deformity.

79
Ultrasonography
(Fig. 3.28) enable tangential X-ray exposure to the articular
surface and facilitate this assessment after fixation. With
increasing using of volar plates for treatment of distal radius
fractures, extensor tendon rupture from screw protrusion
dorsally is a concern. Detection of dorsal screw protrusion
from a lateral X-ray has a sensitivity of only 56%26 and on
average, protrusion of the radial-most screw can only be
detected at a minimum of 6.5 mm of protrusion.27 Special
X-ray views can be done to improve detection of screw protru­
sion (Box 3.4 and Fig. 3.29)
The availability of fluoroscopy in many clinics and operat­
ing rooms allows the dynamic assessment of many hand and
wrist conditions. Smaller, lower cost, and radiation28 mini
c-arms have also lowered the barrier to acquiring such facili­
ties. The clinician can operate the c-arm to obtain the best
view and view changes in the relationships of the bones “live”
with motion, loading, or application of stress. Fluoroscopy is
helpful for assessing carpal instability, including SL injuries29
(Video 3.1
) and midcarpal instability (Video 3.2
), guiding
percutaneous insertion of implants, and assessing the position
of implants.30
Ultrasonography
Diagnostic ultrasound has advanced much recently. New
ultra-high frequency probes and smaller probe sizes allow
higher-quality images of the hand and wrist.31 Ultrasound’s
safety, portability, and relatively low cost have led to wider
use, especially by clinicians operating the machines them­
selves.32 One additional advantage over other forms of
imaging, like CT scanning or MRI, is that it allows dynamic
and real-time assessment. The addition of Doppler imaging
enhances the information provided by the ultrasound study.31
Ultrasound uses the acoustic properties of generated sound
waves to form images.32 The ultrasound transducer generates
the sound waves in pulses. When the transducer is applied
over the surface of the part to be examined, the sound waves
pass through tissues. At the junction of two tissues, an acoustic
interface occurs. When the sound waves meet an acoustic
interface, some of the sound wave energy is reflected, while
the rest continues to be transmitted deeper. The greater the
differences in material properties of the adjacent tissues, the
Fig. 3.19  Stress view: true lateral of the wrist. Notice the loss of radioulnar overlap
due to the dorsal subluxation of the distal radioulnar joint. The pisiform lies
between the volar aspect of the scaphoid and capitate, so the view is accurate.
Injuries to the wrist ligaments, for example the SL ligament,
can lead to carpal instability. In severe cases, this can be seen
on the usual wrist views as loss of the normal relationships
between the carpal bones. In SL instability, this is typically
seen as a dorsal intercalated segmental instability deformity
(Fig. 3.22) with an increase in the SL angle, and dorsal tilt in
the radiolunate angles (Fig. 3.23). However, in milder forms
of instability, application of loads and/or positioning of the
wrist are necessary to bring out these dynamic changes in
carpal relationships. The clenched-fist PA series of the wrist is
one technique used to diagnose dynamic carpal instability
(Fig. 3.24).
Ulnar abutment syndrome is a common cause of ulnar-
sided wrist pain. The use of a clenched-fist pronated view of
the wrist enhances the ulnar variance and may demonstrate
the abutment (Fig. 3.25).24
Wrist evaluation in distal radius fractures
Distal radius fractures are the commonest fractures encoun­
tered in the emergency room.25 Loss of the normal distal
radius indices (Figs. 3.26 & 3.27) due to fracture displacement
can affect final outcome. Unstable and displaced fractures are
commonly treated with plates and screws. Screws placed
subchondrally offer the greatest rigidity in fixation. However,
conventional wrist views do not allow accurate assessment of
screw position, especially when a distal fracture line compels
the surgeon to place the screws in close proximity to the
radiocarpal joint. This is because standard views do not
compensate for the normal anatomic tilt of the radius. Radio­
graphs angled 22 degree lateral and 11 degree posteroanterior
BOX 3.4  Additional views for assessment of dorsal screw
penetration from distal radius
Supinated
This view aligns the X-ray beam to the radial side of the dorsal
cortex, allowing easier detection of prominent screws in the first and
second dorsal compartment.
Pronated
This view aligns the X-ray beam to the dorsal-ulnar corner of the
distal radius and allow easier detection of prominent screws in the
fourth extensor compartment.
Dorsal horizon view
This view is done with the wrist hyperflexed and the X-ray beam
aimed along the longitudinal axis of the radius.

80
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
Fig. 3.20  Scaphoid series to assess for a scaphoid fracture. Notice the fracture is best seen in the scaphoid view on the lower left corner of the series.
more energy is reflected. The reflected sound wave is received
in the transducer. This is then converted to an electrical signal
for processing. The greater the sound reflected, the larger
the amplitude of the reflected wave, and consequently, the
brighter the image.
Ultrasound has its disadvantages (Table 3.2). It only allows
a small field of view, so is best used for a focused examination
of a small area. Differentiation of different soft-tissue tumors
of the hand and wrist, apart from ganglia, is also inadequate.33
The problem of anisotropy can lead to reduced echogenicity
when tendons are being imaged. Anisotropy is a phenomenon
where the echogenicity of the tendon changes when the
incidence of the sound beam changes. This can lead to the
operator mistaking anisotropy for pathology like tendon
degeneration. A careful complete assessment of suspected
tendon lesions will detect this phenomenon.34
One major advantage of musculoskeletal ultrasound is the
ability to do real-time and dynamic assessments. An area in
the hand and wrist where this is particularly useful is in the
assessment of tendons. For example, flexor tendon bowstring­
ing due to pulley rupture can be dynamically demonstrated
on ultrasound by the patient. Tendinopathies, partial and
complete tendon tears, or lacerations can be demonstrated
(Fig. 3.30). Ultrasound has also been shown to be able to detect
changes in trigger finger35 and DeQuervain’s tenosynovitis.36
Table 3.2  Advantages and disadvantages of ultrasound
Advantages
Disadvantages
• No ionizing radiation
• Allows real-time and dynamic
assessment by operator
• Relatively cheap to acquire
and operate
• Very limited field of view
• Highly operator-dependent
• Limited usefulness for
assessment of soft-tissue
masses

81
Ultrasonography
Fig. 3.21  (A) Carpal tunnel view of the wrist demonstrating several structures:
trapezium (Tz), pisiform (P), and hook of hamate (HH). A fracture across the hook
of the hamate is indicated by the black arrow. The trapezial ridge (indicated by
white arrow) is an unusual site for fractures that is best seen on this projection. (B)
Same patient with carpal tunnel view of the same wrist following open reduction
and screw fixation. Notice that the fracture line is no longer visible.
P
HH
Tz
A
B
A
Fig. 3.22  DISI is the acronym for dorsal
intercalated segmental instability. The term
“intercalated segment” refers to the proximal
carpal row bones. (A) This row has no direct
musculotendinous insertions, hence it is
“intercalated.” “Dorsal” refers to the
dorsiflexion of the lunate seen in the
radiograph. A scapholunate dissociation is
the commonest cause of a DISI deformity,
and will show an increased scapholunate
angle as above. (B) On the posteroanterior
view, the scaphoid will appear flexed and
foreshortened with a positive cortical ring
sign as seen.
B
Fig. 3.23  Carpal indices. Axes are drawn based on the true lateral wrist
radiograph. (A) The scaphoid (S) is represented by a tangential line that connects
the two palmar convexities of the bone. (B) The lunate (L) axis is perpendicular to a
line that joins the two distal horns of the bone. (C) The capitate (C) axis is
determined by the center of the two proximal and distal articular surfaces. (D) The
axis of the radius (R) is obtained by tracing perpendicular lines to its distal third
and connecting the center of these lines. (E) Normal scapholunate angles. (F)
Normal capitolunate angles. (G) Normal radiolunate angles. DISI, dorsal intercalated
segmental instability.
Scapholunate angle
Capitolunate angle
Radiolunate angle
S
L
C
R
Normal 30–80º
Normal is ±15º
Dorsal tilt
of >15º DISI
A
B
C
E
F
G
D

82
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
Fig. 3.24  These radiographs show a
patient with dynamic scapholunate
instability. The scapholunate interval is
normal on an unloaded wrist (A), but
widens on clenching the fist (B).
A
B
Fig. 3.25  This patient presented with signs
and symptoms of ulnar carpal abutment. The
positive ulnar variance (A) is increased with
the pronated clenched-fist view (B).
A
B

83
Computed tomography
Fig. 3.26  Normal distal radius indices. PA, Posteroanterior.
PA wrist
A: Radial height. Normal = 11–12mm, Range = 8–18mm
B: Radial inclination. Normal = 22–23º, Range = 13–30º
C: Volar tilt. Normal = 11–12º, Range = 0–28º
A
PA wrist
Lateral wrist
B
C
Fig. 3.27  Distal radius fracture with loss of the
normal radial height, inclination, and volar tilt.
Fig. 3.28  Position of the limb and direction of X-ray beam for an anatomical tilt
lateral view of the distal radius. This view is very helpful for assessing screw
position when applying plates and screws close to the articular surface in distal
radius fractures.
Incident beam of X-ray perpendicular
to the X-ray cassette and centered
over the wrist joint
Firm soft radiolucent support
inclining elbow at 22º to
horizontal
X-ray cassette
In trigger finger, ultrasound has also been used to guide
steroid injection and percutaneous release.37,38
Diagnostic ultrasonography has also been applied to other
wrist and hand disorders. Carpal ligament injuries and trian­
gular fibrocartilage (TFCC) tears can be assessed using
ultrasonography.39 For TFCC tears, ultrasonography has been
shown to have good correlation with MRI.40 Ultrasonography
of the carpal tunnel may be helpful to assess carpal tunnel
syndrome. The median nerve is enlarged in carpal tunnel
syndrome, with changes in the echogenicity of the nerve. The
most consistent finding across the studies is the increase of
the cross-sectional area of the median nerve at the level of
the pisiform bone.41 Ultrasound is also useful for clinical
assessment if other causes of carpal tunnel syndrome are
suspected (e.g., mass lesions in the carpal tunnel or
tenosynovitis).
Computed tomography
CT is a key advanced imaging modality for the assessment of
hand and wrist disorders, particularly those affecting the

84
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
Fig. 3.29  (A) Standard PA and lateral wrist X-rays showing a distal radius fracture
post-fixation. (B) Supination and pronation views showing dorsal screw penetration.
(C) Dorsal horizon view showing dorsal screw penetration.
A
B
C
bones and joints. Advances in CT scanning technology have
resulted in shorter scanning times, and allow manipulation
and reformatting of the CT data for image reconstruction in
multiple planes and the development of three-dimensional
images. The advantages and disadvantages of CT are shown
in Table 3.3.
Fractures and dislocations
CT is useful in evaluation of the hand and wrist for bony and
joint injuries that are not well visualized or assessed using
radiographs. Examples of these include scaphoid fractures,
CMC joint injuries (see discussion in radiography section,
above), and other articular fractures (Fig. 3.31).
Scaphoid fractures are often difficult to detect on plain
radiology after an acute injury. A repeat radiograph several
weeks later or other radiological investigations like CT scan,
MRI, and bone scans are often employed to detect an occult
scaphoid fracture.42 In one study, multidetector CT was shown
to be as effective as MRI in the detection of such occult frac­
tures.43 In the management of scaphoid fractures, CT scan is
useful in evaluating fracture union,44 as plain radiography has
been shown to have poor interobserver agreement for assess­
ing scaphoid union.45 CT scans along the long axis of the
scaphoid46 improve the ability to evaluate the scaphoid for
fractures, and assess for any displacement or humpback
deformity.47 CT scan is also useful for the evaluation of other
carpal fractures.48

85
Computed tomography
Wrist radiographs provide a first evaluation of the distal
radius fractures. In an acute fracture, patient positioning is
hindered by pain, and suboptimal radiographs are common.
Radiography can over- and underestimate the articular
step-off in 30% of intra-articular fractures.49 CT scans of the
wrist can improve assessment, which has an impact on
clinical decision-making (Fig. 3.32). CT scanning and three-
dimensional reconstruction are also helpful in complex frac­
tures of the distal radius and ulna to help in surgical planning.
In distal radius malunion, CT is recommended to assess the
deformity50 and as a basis for computer-assisted surgical
techniques.51,52
A
Fig. 3.30  This patient presented with difficulty in finger flexion after an injury.
Ultrasonography showed a partial tear of flexor tendon at the level of the head of
middle phalanx, more obvious on flexion against resistance (dark area, arrowed on
longitudinal section image and between calipers on transverse section image).
(Courtesy of Dr. Ian Tsou, Singapore.)
B
Table 3.3  Advantages and disadvantages of computed
tomography (CT)
Advantages
Disadvantages
• Quick scanning with modern
machines
• Capacity to image in any anatomic
plane (multiplanar imaging) and
three-dimensional reconstruction
• Excellent for assessing complex or
poorly visualized fractures in the
hand and wrist
• CT angiography can be performed
at the same sitting to assess the
vascular tree
• Inferior to magnetic
resonance imaging for
imaging of soft tissue
• Requires expose to
ionizing radiation
• Prone to artifacts from
patient movement and
implants
A
Fig. 3.31  This displaced fracture of the radial condyle of the proximal phalanx
(small finger) is well visualized on the computed tomography (A) and (B), but
obscured on plain radiograph. There is a concomitant fracture of phalanx base, seen
in (B).
B
CT is also helpful in suspected DRUJ instability. A proper
lateral view of the wrist is the key initial imaging. There are
several pitfalls associated with this. Proper positioning of the
wrist for a proper lateral wrist radiograph or stress views may
not be possible because of pain or other factors. The instability
may be subtle, manifesting only in certain wrist positions or
under load. Bilateral axial cut CT scans of the wrists in the

86
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
The usefulness of CT is often enhanced when coupled with
volume-rendering techniques. These allow clearer imaging of
subtle fractures and complex injuries. They are also helpful in
the evaluation of suspected infections or neoplastic disease.
After operative fixation of fractures, volume rendering can
improve the quality of imaging by eliminating streak arti­
facts.60 Using intravenous contrast, CT angiography can be
performed (see section on vascular imaging techniques for the
upper extremity, below).
Magnetic resonance imaging
MRI of the hand and wrist has come to the forefront in the
last decade. It is the preferred modality for imaging soft tissue,
particularly those associated with trauma and neoplastic
conditions. Larger and more powerful magnets, improved
gradient strength and speed, dedicated coils providing favor­
able signal-to-noise ratios, and the capability of supporting
small fields of view enable visualization of pathology in
exquisite anatomic detail. The advantages and disadvantages
of MRI are shown in Table 3.4.
MRI basics
MRI employs magnetic fields and radiowaves rather than
ionizing radiation. The magnetic field is generated by an
electromagnetic coil with field strengths ranging from 1.5 to
3.0 Tesla (T) (15 000–30 000 gauss). Gradient (secondary)
magnets fine-tune and focus the MRI on specific areas of
interest. MRI coils send and receive radiofrequency pulses
that are used to create images. In general, the smaller the coil
and the more centrally located an anatomic structure is within
the coil, the sharper the image and the higher the signal-to-
noise ratio.
MR differentiates tissues such as fat, muscle, bone, blood,
and water on the basis of their innate magnetic characteristics
and the varying tissue concentration of hydrogen ions
(protons). Each proton spins like a top, around an axis. In the
absence of a magnetic field, their axes are randomly oriented
and produce no net magnetic effect. In the MRI scanner, the
magnetic field generated causes the axes of rotation of
the protons to align themselves with the longitudinal axes of
neutral, pronated, and supinated position provide critical
information to allow better evaluation of these injuries (Fig.
3.33). For CT evaluation of DRUJ instability, different radio­
graphic parameters have been described.53–56 Our institution
uses the subluxation ratio method described by Park and
Kim.57
Other applications of CT
CT is also helpful for the evaluation of bony tumors in the
hand. CT can help characterize the bony tumor and assess for
bony destruction. In these situations, MRI is often comple­
mentary. Fine-cut CTs are the modality of choice for osteoid
osteoma.58
There are limitations to the use of CT. Soft-tissue resolution
is limited, so it is less useful than MRI for imaging soft-tissue
disorders. Artifacts from various sources, including patient
movement and metal implants, hinder evaluation. Software
techniques can be used to limit these artifacts, but often at the
cost of resolution at the site of interest.59
Fig. 3.32  Coronal computed tomography (CT) image of distal radius fracture.
Extension into the radiocarpal joint is seen here but not on the plain radiograph. CT
is helpful for the assessment of intra-articular distal radius fractures with respect to
articular involvement and incongruity, fragment number, and fragment orientation.
Fig. 3.33  Axial computed tomography cut of distal radioulnar joint in neutral
position shows dorsal subluxation of the left joint (right image). This can be
quantified by the use of indices.
Table 3.4  Advantages and disadvantages of magnetic
resonance imaging (MRI)
Advantages
Disadvantages
• Capacity to image in any
anatomic plane (multiplanar
imaging)
• High soft-tissue contrast with
indication of tissue composition
• No ionizing radiation
• Acquisition of three-
dimensional volume data using
gradient echo sequences
• Noninvasive imaging of blood
vessels and other structures
without the use of contrast
(e.g., MR arthrography)
• The high cost of
equipment
• Image artifacts from
motion and ferromagnetic
objects
• Inferior to computed
tomography for imaging
of cortical bone
• Contraindicated in
patients with cardiac
pacemakers, aneurysm
clips, metallic foreign
body, claustrophobia

87
Magnetic resonance imaging
the magnet. Gradient magnets change the alignment of the
rotating protons whilst radiofrequency pulses from the coils
excite the protons to a higher energy level. Cessation of
radiofrequency stimulation induces a tiny current within the
surrounding coil which can be detected and amplified to give
a signal. The time taken for a proton to become magnetized
is known as the T1 relaxation time and the time taken for the
proton to be demagnetized is known as the T2 relaxation time.
The amount of energy released by a tissue is directly propor­
tional to its concentration of protons. It is also the varying
concentration of protons between different tissues that allows
them to be magnetized and demagnetized differentially. This
is the basis of differentiating the soft tissues. The relevant
signals of different tissues on T1- and T2-weighted images are
shown in Table 3.5.
Water can be categorized into free water and bound water.
Free water is found mostly in extracellular fluid whilst bound
water is mostly in intracellular fluid. Free water has long T1
and T2 relaxation times. Hence it typically shows low signal
intensity on T1-weighted images and high signal intensity on
T2-weighted images. Water that is not free is usually bound to
proteins which inhibit motion. This preferentially shortens the
T1 relaxation time more than the T2 relaxation time, hence the
T1 signal is usually of intermediate to high intensity. Examples
of proteinaceous fluid include abscesses, synovial fluid, and
purulent collections.
Clinical applications of MRI
MRI for soft-tissue masses
MRI is the preferred modality for imaging soft-tissue masses
in the hand and wrist. The majority of soft-tissue masses
in the hand and wrist are benign.61 MRI characteristics of
the common tumors are well described in literature and
references.62–64 MRI, with its multiplanar imaging capability,
tissue characterization of lesions, and ability to define rela­
tionship of lesions to surrounding tissue and vessels (includ­
ing tumor invasion), allows one in many circumstances to
arrive at a specific diagnosis.
Ganglion cysts
Ganglia show low to intermediate signals on T1-weighted
images and high signals on T2-weighted images. They may be
Table 3.5  Signal intensities of tissues on T1- and T2-weighted
magnetic resonance images
Tissue
Signal T1-
weighted image
Signal T2-
weighted image
Fluid (free water)
Low
High
Fluid (proteinaceous)
Intermediate
High
Fat
High
High
Muscle
Intermediate
Intermediate
Cartilage
Intermediate
High
Cortical bone
Low
Low
Bone marrow (yellow)
High
Intermediate
Bone marrow (red)
Low
Intermediate
uniloculated or multiloculated and contain proteinaceous
synovial fluid. This accounts for its isointense or slightly
hypointense signal on T1-weighted images compared to
muscle (Fig. 3.34). Demonstration of a stalk can usually reveal
its site of origin. Hemorrhage into a ganglion cyst can result
in high signal intensity on T1-weighted images. A ganglion
A
Fig. 3.34  This patient presented with a firm mass in the left thenar eminence that
was difficult to characterize clinically. Radiographs were normal. (A) Magnetic
resonance imaging shows a mass with typical high signal intensity during the
T2-weighted sequence. (B) A sagittal fat suppression short tau inversion recovery
sequence shows the stalk of the ganglion connecting to the sheath of the flexor
carpi radialis (indicative arrow) with the scaphoid (S) in close relation.
B

88
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
shows no enhancement on administration of intravenous
gadolinium; however, its capsule and septa will usually show
enhancement. Ganglion cysts occurring in “classic” locations
such as the dorsum of the wrist can usually be diagnosed
clinically and do not require MRI.
Giant cell tumors of the tendon sheath (GCTTS)
Synonymous with focal pigmented villonodular synovitis,
these benign tumors of synovial origin typically occur in the
digits over the volar aspect, and arise from the tendon sheath,
joint capsule, fascia, or ligaments. They contain multinucle­
ated giant cells and have intra- and extracellular hemosiderin
deposition. On MRI, GCTTS appear as solid masses, hypoin­
tense on both T1- and T2-weighted images. The low signal is
due to the paramagnetic effect of hemosiderin deposition. On
T1-and T2-weighted images, these masses appear isointense
with skeletal muscle. Uniform enhancement is seen following
administration of intravenous gadolinium contrast (Fig. 3.35).
Lipomas
Lipomas are less common in the hand and wrist than in other
parts of the body. In the hand, they usually occur over the
palmar aspect, either in the thenar or hypothenar eminence
or in the mid-palmar space. They show the same homoge­
neous high signal intensity as fat on T1-weighted images and
superficial lipomata can appear inconspicuous. They show
low signals on short tau inversion recovery (STIR) and T2-
weighted sequences. The presence of distinct nodules or solid
components may suggest a liposarcoma.
Hemangiomas
Hemangiomas are benign tumors classified into capillary,
cavernous, and venous types. T1-weighted signal intensity
varies from low, to high, depending on the amount of fat
contained. On T2-weighted sequences, they tend to be lobu­
lated with well-defined borders and very high signal intensity
from pooled blood. A lace-like pattern of enhancement may
be seen on T1-weighted images due to fibrofatty elements.
Signal voids may be present on all MR sequences as a conse­
quence of phleboliths within the hemangiomas. The hetero­
geneous nature of hemangiomas thus makes preoperative
diagnosis by MRI less certain.61
Enchondromas
Enchondromas are the most common benign tumors of bone
that are found in the hand. Problems associated with enchon­
dromas are pathological fractures and the rare occurrence of
malignant transformation. Radiography demonstrates a lytic
expansile lesion with a clear zone of transition and speckled
calcifications. Cortical thinning is present and may be associ­
ated with a pathological fracture. On MRI, they appear as
high-signal-intensity lobulated tumors on fat suppression (FS)
STIR and T2-weighted sequences. They show low to interme­
diate signal intensity on T1-weighted sequences.
MRI for wrist and hand trauma
This application of MRI has become more widespread in the
last two decades, in particular for ligamentous injuries. A
further advantage of MRI is its superior imaging of bone
A
Fig. 3.35  This man presented with a firm painless enlarging mass over the dorsum
of the left hand. Magnetic resonance imaging shows a low signal intensity mass
over the third carpometacarpal junction, seen on (A) sagittal T1-weighted sequence
and (B) axial T2-weighted sequence.
B
marrow and vascularity of bone with a wide range of applica­
tions, including diagnosing AVN, marrow edema, and inflam­
mation, as well as infection.
Occult scaphoid and carpal fractures
MRI is the most sensitive and specific imaging modality for
occult scaphoid fractures, although its cost may be greater or

89
Magnetic resonance imaging
An intact ligament is shown as a homogeneous black signal
or band on a proton density-weighted GRE sequence or a
T1-weighted spin echo sequence on coronal slices. An abnor­
mal ligament shows increased signal intensity on T2-weighted
sequences or STIR sequences, segmental defect, increased
length, thickening, thinning, and nonvisualization.68 MR
arthrography can be performed with saline or dilute gado­
linium injected into the joint, enhancing the detection of liga­
ments and TFCC perforations.
Thumb ulnar collateral ligament injuries
A poorly treated complete tear of the ulnar collateral ligament
of the thumb metacarpophalangeal joint can lead to painful
and chronic instability. MRI is valuable in assessing for com­
plete ligamentous disruption, a diagnosis that may be difficult
to make in early or acute presentations (Fig. 3.37). Such
imaging helps exclude a Stener lesion,69 where the adductor
aponeurosis becomes interposed between the two ends of the
ruptured ligament, preventing ligament healing.
Scapholunate interosseous ligament injury
This is the most common intrinsic wrist ligament injury.
Presentations vary from occult SL joint ganglions, dynamic SL
instability, to static SL dissociation. SL dissociation is the com­
monest cause of carpal instability. Early recognition of SL
instability allows treatment and prevention of late arthritis.
Features which support a tear of the SL ligament include
widening of the SL interval, fluid signal traversing the SL
or LT ligaments on the fat-suppressed fast spin echo (FSE)
T1-weighted sequence, or STIR sequence (Fig. 3.38). Proton
density sequences as well as T2-weighted sequences with FS
can also reveal morphological abnormalities and absence of
the SL ligament. The same criteria also apply for evaluating
the less common LT ligament injuries.
MRI for evaluating ulnar-sided wrist pain
Ulnar-sided wrist pain is a common and challenging problem.
Causes of ulnar-sided wrist pain include injuries to the TFCC,
LT ligament injuries, and ulnocarpal abutment syndrome.
Other diagnoses include fractures and nonunion of frac­
tures, especially of the ulnar styloid, DRUJ problems, and
tendinopathies.
TFCC tears
TFCC injuries are classified into two groups: those occurring
acutely and degenerative lesions. In the latter group, lesions
occur in the central portion of the TFCC and the incidence
increases with advancing age. Acute traumatic tears of the
TFCC usually occur following a forced axial load of the wrist
in an extended and ulnar-deviated position. Acute tears of the
TFCC resulting in detachment from the fovea or detachment
from its radial border can result in DRUJ instability. The gold
standard for evaluation of TFCC injuries is arthroscopy.
MRI has been increasingly used for imaging the TFCC. The
sequence which best demonstrates the TFCC is the FS FSE
T1-weighted and GRE T2 sequence.70 GRE sequences which
mimic FS FSE T1-weighted sequences such as the proton
density-weighted GRE sequence depicts TFCC disruptions
even more distinctly (Fig. 3.39). With the advent of 3.0-T MRI
equitable compared to the classic diagnostic algorithm.65,66 An
area of a linear band of low signal intensity on T1-weighted
sequences, coupled with an area of high signal intensity on
FS T2-weighted sequences or STIR sequences, has the highest
combined sensitivity and specificity. Cortical fracture lines are
best seen on a STIR or gradient echo (GRE) sequence. Use of
MRI for diagnosis of radiographically occult fractures is not
limited to the scaphoid, but includes other carpal bone frac­
tures which are difficult to image on radiography.67 The added
value of using MRI for detection of occult carpal bone frac­
tures is that it also demonstrates ligament injuries which can
clinically mimic carpal fractures (Fig. 3.36). Bone bruising, a
term synonymous with bone contusion, exhibits exactly the
same MRI findings as occult fractures do with the exception
of a cortical break. This diagnosis is made in the setting of a
positive history of preceding trauma and positive MRI find­
ings, as described above.
Ligamentous injuries of the hand and wrist
Suspected ligamentous injures of the hand and wrist are prob­
ably the most common indication for ordering an MRI. SL and
LT ligament tears as well as tears of interphalangeal or meta­
carpophalangeal joint ligaments are frequent clinical prob­
lems. Another large group of wrist pathologies – ulnar-sided
wrist pain, including but not limited to tears of the TFCC,
ulnocarpal abutment, DRUJ and tendinitis – is considered
separately in the next section.
Fig. 3.36  This patient presented with persistent dorsoradial-sided wrist pain after a
fall. He had initially been seen by a general practitioner and diagnosed as having a
sprain. Magnetic resonance imaging coronal fast spin echo proton density
sequences with fat suppression showed two areas (white arrows) of high signal
intensity in the scaphoid proximal pole and waist (associated with fracture). The
signal enhancement in the proximal pole is due to an injury of the scapholunate
ligament, noting a normal ligamentous structure of the lunotriquetral ligament
(black arrow).

90
SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
A
Fig. 3.37  This 15-year-old girl presented with pain at the ulnar aspect of the
metacarpophalangeal joint of her right thumb after an abduction injury from a fall.
Plain posteroanterior and lateral radiographs showed no abnormalities. Clinical
assessment for joint instability was difficult because of her anxiety and pain and a
magnetic resonance imaging scan was performed. The coronal fast spin echo
proton density sequence, a variant form of gradient echo sequences, reveals a distal
avulsion/rupture (A) of the ulnar collateral ligament (black arrow). The radial
collateral ligament on the other hand is intact and smoothly inserts or joins the
base of the proximal phalanx of the thumb. (B) The short tau inversion recovery
sequence shows bright signal intensity at the site of rupture seen on the proton
density sequence, correlating with an acute tear or rupture of the ligament.
B
A
Fig. 3.38  This patient presented with right-sided wrist pain. He had tenderness
over the scapholunate junction over the dorsum of the wrist. Radiography showed a
normal scapholunate angle on lateral wrist projections and no widening of the
scapholunate interval on posteroanterior projections of the wrist. Magnetic
resonance imaging coronal fast spin echo proton density sequences with fat
suppression (A) showed widening of the scapholunate (SL) interval (star) with
absence of the membranous portion of the ligament. The membranous portion of
the lunotriquetral (LT) ligament is intact (white arrow). The next sequence shows a
more dorsal section of the proximal carpal row with an intact LT ligament (black
arrow) and disrupted SL ligament with abnormal fluid signal traversing it and a
thickened and fibrillar morphology (white arrow) (B).
B

91
Magnetic resonance imaging
A
Fig. 3.39  This 27-year-old male presented with right ulnar-sided wrist pain of 1
year’s duration. There was a preceding history of a fall during rollerblading.
Magnetic resonance imaging proton density-weighted sequences show that the
portion of the triangular fibrocartilage (small arrow) that inserts into the fovea (big
arrow) has been avulsed off its insertion (A). In a different patient, the triangular
fibrocartilage with its insertion into the fovea preserved (white arrow) is shown (B).
This patient had instead a scapholunate ligament injury.
B
machines, the sensitivity and specificity of MRI for detection
of TFCC lesions exceed that of 1.5-T machines.71,72
Ulnocarpal abutment
This is a degenerative condition related to excessive load-
bearing across the ulnar side of the wrist. An ulna positive
variance may be present. Radiography may be normal or may
show subchondral cyst formation in the lunate and/or trique­
trum. Stress films can demonstrate dynamic increase in ulnar
length relative to the radius (pronated grip film of the wrist).
MRI shows foci of low signal intensities in the lunate and
triquetrum and occasionally in the ulnar head, reflecting
chondromalacia. On FS STIR or FS T2-weighted sequences,
these same areas show bright signal intensities from bone
marrow edema or secondary to the presence of cyst formation
(Fig. 3.40).
DRUJ instability and tendinopathies
CT is the preferred imaging modality for DRUJ instability and
subluxation. MRI however allows visualization of the liga­
ments and the insertion of the TFCC into the fovea, which
contributes to stability of the DRUJ. Furthermore, high signal
intensities on FS STIR sequence will suggest reactive marrow
edema from persistent DRUJ instability and synovitis. The
relationship of the ulnar head to the distal end of the radius
and DRUJ subluxation is best assessed on an axial FSE T1-
weighted sequence. A halo of high signal enhancement can be
seen in tendinopathies on axial slices during an FS STIR
sequence or an FS T2-weighted sequence. In addition, there
may be thickening of the tendon and abnormal signal within
the tendon itself on coronal slices.
MRI for evaluation of fracture nonunion
Scaphoid fractures are prone to nonunion. Radiography to
assess for fracture healing lacks a high degree of sensitivity
and specificity. The MRI criterion to assess union is the pres­
ence on T1-weighted sequences of normal signal intensity
crossing the previous fracture line.73 Nonunion is shown by
the presence of high signal intensity at the fracture line on FS
STIR or FS T2-weighted sequences or the GRE equivalents.
MRI for avascular necrosis (AVN) in scaphoid
fracture nonunion
The proximal pole of the scaphoid is prone to AVN following
a fracture due to its retrograde vascular axis pattern.74 Radio­
graphs can show changes associated with AVN, including
sclerosis of the proximal fragment, osseous absorption, and
cysts. MRI can detect AVN at an earlier stage. Knowing the
vascularity of the proximal fragment guides clinical decision-
making, including whether to use vascularized or nonvascu­
larized grafts. Low signal intensity of the proximal fragment
on T1-weighted sequences indicates replacement of the normal
marrow with fibrous tissue. High signal intensity of the
proximal pole on gadolinium contrast-enhanced study sug­
gests that vascularity is preserved. This finding has not been
consistently proven in all studies, and the relative enhance­
ment should be significantly greater than the surrounding
carpal bones.73
Kienbock’s disease
Idiopathic AVN of the lunate is relatively uncommon when
compared with post-traumatic AVN of the scaphoid. A nega­
tive ulnar variance has been shown to be associated with
an increased risk of Kienbock’s disease. MRI is of value in
detecting early disease, prognosticating, and for monitoring

92
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CHAPTER 3 • Diagnostic imaging of the hand and wrist
A
Fig. 3.40  This patient presented with persistent right ulnar-sided wrist pain of 6
months’ duration and he complained of inability, in particular in hammering
objects. He had tenderness over the ulnar fovea and a positive ulnocarpal grind.
Plain film radiography (A) showed no fractures of the ulnar styloid. There was,
however, a subchondral cyst seen in the proximal ulnar corner of the lunate (black
arrow) and there was positive ulnar variance (white arrow). On magnetic resonance
imaging, the fat suppression short tau inversion recovery sequence showed high
signal intensity in the same corresponding area of the lunate (B). Note that the
triangular fibrocartilage and the ulnar head (white arrows) show no signal
enhancement which would typify more advanced involvement.
B
revascularization of the lunate following treatment.75 AVN of
the lunate is suggested by low signal intensity on T1-weighted
sequence as marrow is replaced by fibrous tissue. Areas of
high signal intensity may be seen on FS T2-weighted sequence
or FSE FS STIR sequences, suggesting marrow edema or
neovascularization (Fig. 3.41). Low signal intensity on such
sequences likely indicates established ischemic necrosis
without any further bone reactive changes.
Osteomyelitis
Osteomyelitis of the hand and wrist bones is relatively
uncommon. It is usually a consequence of previous surgical
intervention for fractures or other procedures. Traditionally,
either scintigraphy or MRI has been used when plain film
radiography has been negative in suspected osteomyelitis.
MRI has the advantage of discriminating marrow abnormali­
ties from joint and soft-tissue changes. Areas of marrow
involvement will show low signal on T1-weighted sequence
and high signal intensity on T2-weighted sequence.
Vascular imaging techniques for the
upper extremity
Digital subtraction angiography (DSA) is the gold standard
for vascular imaging of the extremities.76,77 Improvements in
CT angiography and magnetic resonance angiography (MRA)
make them increasingly viable alternatives in vascular
imaging of the upper extremity. Arterial imaging of the upper
limb is usually performed in two different clinical settings: the
detection of extremity vascular injury following trauma to
the limb, and assessment of vascular disorders involving the
upper limb.
The indications for angiography following trauma are:
decreased or absent pulse or blood pressure, cold limb, bruit
or murmur, uncontrolled bleeding or increasing hematoma,
neurologic deficit, and proximity of the injury to vascular
structures.78 When the clinical condition warrants immediate
surgery, conventional angiography is contraindicated. Knife
injuries (80%) and blunt trauma (67%) are more likely to be
associated with vascular abnormalities, followed by gunshot
wounds (44%).78
DSA has a role in the assessment of the vascular tree in
peripheral arteriosclerotic disease, connective tissue diseases,
thoracic outlet syndrome, and Raynaud’s phenomenon. It is
also useful for assessing arteriovenous fistulae and vascular
tumors and malformation of the upper limb.
CT angiography (CTA) is less invasive than DSA and can
additionally assess vessel wall and extraluminal pathology.
The data obtained allow reconstruction in three-dimensional
and multiple planes. The advancements in CT technology,
new protocols, and availability of CTs in proximity of many
emergency departments have made CTA an increasingly
attractive option for the assessment of the extremity vascular
tree following trauma.79,80 In extremity trauma, CTA can
identify arterial injuries, including pseudoaneurysm, active
arterial hemorrhage, arteriovenous fistulae, occlusion, intimal
injury, or vasospasm.81 Venous injury may also be assessed.
CTA has also been shown to be useful in the evaluation of
suspected extremity vascular trauma in pediatric patients.82 In

93
Radionuclide imaging
A
Fig. 3.41  A karate enthusiast presented with right wrist central dorsal pain of
gradual onset that was associated with morning stiffness as well as weakness of
grip over the passage of time. Radiography was normal aside from the suggestion
of an area of faint linear sclerosis in the lunate. Magnetic resonance imaging fast
spin echo T1-weighted sequence showed loss of normal marrow signal affecting the
radial corner of the lunate (A). Fast spin echo fat suppression short tau inversion
recovery sequences showed diffuse marrow enhancement, sparing only the proximal
ulnar tip of the lunate (B).
B
intimal injury, vasospasm, or adjacent hematoma, is difficult.79
Imaging of the distal vascular tree is also difficult. DSA also
offers an advantage where there is a possibility of endovascu­
lar treatment, for example in an arteriovenous fistula. The
sensitivity and specificity of CT arteriography have been
shown to be 95.1% and 98.7% in cases of suspected vascular
injury following blunt or penetrating injury.83
MRA offers advantages over conventional DSA for extrem­
ity vascular imaging. MRA is less invasive, does not require
iodinated contrast, and can simultaneously demonstrate
extraluminal disease.84 The angiographic effect in MRA is
created by various techniques with or without contrast
enhancement with gadolinium chelate agent. The use of
contrast-enhanced MRA with a dedicated surface coil enables
quick and high-quality examination of the hand vascular
tree.85
MRA of the wrist and hand has a potential number of
indications for its use and has been employed successfully in
imaging of vascular malformations, vascular trauma, and
vascular occlusion.86 MRA is performed making use of a
coronal volume three-dimensional spoiled GRE time-of-flight
sequence and dynamic administration of intravenous gado­
linium contrast with image acquisition using a wrist coil. The
inherent contrast from protons in flowing blood relative to the
saturated protons in the stationary soft tissue produces
the image which is formulated based on an MR algorithm
which deletes the signal from the soft tissue. MRA has the
potential to depict pathologic change in vessels of up to 1 mm
in diameter and can reliably show the superficial and deep
palmar arches of the hand (Fig. 3.42). Some of the disadvan­
tages of MRA include the inferior resolution of vasculature at
1 mm diameter or less, susceptibility to motion artifacts, as
well as flow artifacts at sites of severe stenosis or thrombosis
where a high signal intensity may be mistaken for flowing
blood. MRA is useful in patients with renal impairment where
intravascular ionic contrast could cause further nephrotoxic
damage, as well as in pediatric patients.
Radionuclide imaging
Radionuclide imaging is a highly sensitive imaging modal­
ity87 with applications in hand and wrist conditions. It can be
positive even when conventional imaging techniques are
unable to visualize the condition. The main limitation of
radionuclide imaging is its lack of specificity. This is because
the tracers used reflect function.88 The imaging detail required
to differentiate physiological and pathological processes is
often lacking in these scans. Therefore it is most useful as a
screening tool. The most common radionuclide musculoskel­
etal imaging is bone scintigraphy with technetium-99m-
labelled diphosphonates. The three-phase bone scan is highly
sensitive for osteomyelitis. However, similar findings can be
mimicked by conditions such as tumors, fractures, and joint
neuropathy. The use of indium-111-labeled autologous leuko­
cytes can improve its specificity.89 Bone scintigraphy is also
useful for diagnosis of complex regional pain syndrome
(reflex sympathetic dystrophy),90 occult fractures of the scaph­
oid,91 and metastatic disease.92 Newer modalities, such as the
combination of scintigraphy with morphologic information,
e.g., single-photon emission CT/CT can improve diagnostic
yields in the extremity.93
pediatric patients, CTA allows imaging of the vascular tree
where DSA is often not possible.
The indications for CTA are similar to that of DSA. There
are limitations with use of CTA for evaluation following
trauma. For example, differentiation of a tapered contour
deformity of CTA, which may variously represent dissection,

94
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CHAPTER 3 • Diagnostic imaging of the hand and wrist
radiation exposure is an occupational risk, with potential
serious effects. There was a report suggesting an increased
cancer risk in orthopedic surgeons working in an institution
with poor compliance to use of radiation protective measures
when working with standard c-arm devices.94 Another study
found a 1.9-fold increased prevalence of cancer and 2.9-fold
increased prevalence of breast cancer in female orthopedic
surgeons when compared with the women of similar age and
race.95
Radiation exposure is directly related to the distance from
the X-ray source. This relationship is described by the inverse
square law. In practical terms, a doubling of the distance from
the source reduces the exposure 4 times. Conversely, a halving
of the distance results in a four-fold increase in radiation
exposure. Some basic knowledge and precautions will mini­
mize radiation to the worker during its operation (Box 3.5).
The choice of fluoroscopy affects the potential radiation
exposure. Compared to conventional fluoroscopy, mini c-arm
fluoroscopy has been shown to emit about half the radiation
exposure.96 However, if the surgeon places his or her hand
in the path of the X-ray beam during intraoperative use of
the mini c-arm, there is a decreased source-to-skin distance
resulting in higher radiation exposure to the hand than when
using the standard c-arm.97,98 While the mini c-arm fluoros­
copy has been widely adopted in hand surgery, we need to
exercise caution during its use to ensure safety of both the
surgeon and the patient. Technological advances will improve
the resolution and utility of these devices, while aiming to
mitigate radiation risks. In tandem, there should be more
research into the long-term risks of exposure during use of
such devices.
Future directions – safety in
fluoroscopy
Fluoroscopy is a powerful imaging tool allowing operative
and dynamic assessment of the bones and joints of the hand.
As the surgeon is often the operator of the machine, this
causes exposure to both direct and scattered radiation. Such
Fig. 3.42  This 23-year-old female had a previous excision of arteriovenous
malformation more than 5 years ago and now presents with skin changes
suggestive of recurrence. Magnetic resonance angiography delineates the palmar
arch well and in addition shows blushes of bright signal intensity over the thumb
pulp, the first web area, and over the index finger (A). This correlated well with the
pigmented changes seen on the clinical photo (B).
A
B
BOX 3.5  Methods to reduce radiation exposure
Increasing the distance between the personnel and the source of
radiation is key, as it has been shown that the rate of radiation
exposure drops significantly beyond the path of the radiation beam
and is minimal beyond 15 cm from the point of focus on the image
intensifier.99
1. Increasing distance from radiation source
•
Placement of the limb directly on the image intensifier (when
using mini C-arms)
•
Uninvolved personnel to position themselves away from the
radiation source
2. Shielding
•
Lead gowns
•
Lead-lined operating rooms
•
Protective goggles
•
Radiation attenuation gloves for operators placing their
hands near radiation source
•
Shielding for anaesthetists and patients
3. Minimizing radiation use
•
Increasing accuracy of fluoroscopy by using laser beams
•
Collimation
•
Avoiding long exposure time

95
Future directions – safety in fluoroscopy
3. Fisher MR, Rogers LF, Hendrix RW. Systematic approach to
identifying fourth and fifth carpometacarpal joint dislocations. AJR
Am J Roentgenol. 1983;140:319–324.
14. Salter RB, Harris R. Injuries involving the epiphyseal plate. J Bone
Joint Surg Am. 1963;45:587–621. This classic instructional lecture course
provides an excellent overview of the growth plate, its injury patterns,
mechanisms and prognosis, as well as radiographic features.
17. Gilula LA. Carpal injuries: analytic approach and case exercises.
AJR Am J Roentgenol. 1979;133:503–517.
32. Smith J, Finnoff JT. Diagnostic and interventional musculoskeletal
ultrasound: part 1. Fundamentals. PM R. 2009;1:64–75. The principles
of medical ultrasonography as applied to the musculoskeletal system are
covered in this first part of a two-part comprehensive review. Part 2 covers
clinical applications of ultrasonography.
48. Kaewlai R, Avery LL, Asrani AV, et al. Multidetector CT of carpal
injuries: anatomy, fractures, and fracture-dislocations1.
Radiographics. 2008;28:1771–1784.
57. Park MJ, Kim JP. Reliability and normal values of various computed
tomography methods for quantifying distal radioulnar joint
translation. J Bone Joint Surg Am. 2008;90:145–153.
64. Ergun T, Lakadamyali H, Derincek A, et al. Magnetic resonance
imaging in the visualization of benign tumors and tumor-like
lesions of hand and wrist. Curr Probl Diagn Radiol. 2010;39:1–16.
This review provides a practical approach to MR evaluation of benign
tumors of the hand and wrist. A comprehensive list of conditions is
covered, with descriptions and images of the MRI findings.
70. Nakamura T, Yabe Y, Horiuchi Y. Fat suppression magnetic
resonance imaging of the triangular fibrocartilage complex.
Comparison with spin echo, gradient echo pulse sequences and
histology. J Hand Surg [Br]. 1999;24:22–26.
84. Stepansky F, Hecht EM, Rivera R, et al. Dynamic MR angiography
of upper extremity vascular disease: pictorial review. Radiographics.
2008;28:e28. MRA is rapidly becoming a viable alternative to digital
subtraction angiography. This article reviews MRA techniques and
protocols, and shows examples of upper extremity pathology diagnosed
with MRA.
87. Love C, Din AS, Tomas MB, et al. Radionuclide bone imaging: an
illustrative review. Radiographics. 2003;23:341–358. Bone scintigraphy
is one of the most frequently performed radionuclide procedures. This
article reviews the basic principles, protocols, normal findings, and
applications of bone scintigraphy.
Access the complete reference list online at

95.e1
References
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SECTION I
CHAPTER 3 • Diagnostic imaging of the hand and wrist
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84. Stepansky F, Hecht EM, Rivera R, et al. Dynamic MR angiography
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subtraction angiography. This article reviews MRA techniques and
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Bone Joint Surg Am. 2007;89:948–952.

SECTION I • Introduction and Principles
4 
Anesthesia for upper extremity surgery
Jonay Hill, Vanila M. Singh, and Subhro K. Sen
SYNOPSIS
■ Optimal perioperative anesthetic outcomes are achieved by a thorough
understanding of anatomy, pharmacology, techniques, and potential
complications.
■ Local anesthetics (LA) make regional anesthesia possible by preventing
the propagation of nerve conduction and by inhibiting or relieving pain.
■ Ultrasound guidance in the use of regional anesthesia has decreased
the need for high volumes of anesthetic.
Introduction
The goal of anesthesia for hand and upper extremity proce­
dures is to provide a comfortable and safe experience for the
patient during surgery. Many options are available for anes­
thesia, with respective benefits and risks. The decision regard­
ing which anesthetic technique is chosen depends on various
factors, including the extent, site, and expected duration of
surgery; need for sedation; general medical health of the
patient, and personal preference.
General anesthesia techniques can be applied for hand and
upper extremity procedures the same as for procedures else­
where. In addition, regional anesthesia techniques can be
applied for procedures involving the upper extremity when
used in the proper setting and patient population. Adjunctive
measures are used to augment local anesthetics to provide
longer duration of action, lower risk of adverse systemic
effects, and less bleeding at the surgical site.
Optimal perioperative anesthetic outcomes are achieved by
a thorough understanding of anatomy, pharmacology, techniques,
potential complications, and general pain management.
Anatomy
The brachial plexus arises from the ventral rami of nerves
C5–8 and T1, with variable contributions from C4 and T2
(Fig. 4.1). These rami unite and diverge forming the roots,
trunks, divisions, cords, and terminal nerves of the brachial
plexus. C5 and C6 roots form the superior trunk, C7 becomes
the middle trunk, and C8 and T1 form the inferior trunk
between the anterior and middle scalene muscles. The three
trunks then divide into anterior and posterior divisions,
coursing over the first rib and lateral to the subclavian artery.
The divisions then reunite to form cords. The anterior divi­
sions of the superior and middle trunk form the lateral cord,
while the anterior division of the inferior trunk forms the
medial cord. The posterior divisions of all three trunks form
the posterior cord. The cords are named according to their
anatomic relationship with the axillary artery. The cords then
divide once again to become the terminal branches of the
brachial plexus. The lateral cord gives rise to the musculocu­
taneous nerve and contributes to the median nerve. The
medial cord also contributes to the median nerve and gives
rise to the ulnar nerve and the medial brachial and ante­
brachial cutaneous nerves. The posterior cord becomes the
axillary and radial nerves.1
Additional nerves outside the brachial plexus can be
important for complete anesthesia of the upper extremity. The
supraclavicular nerve (C3–4) provides sensory innervation to
the “cape” of the shoulder, and the intercostobrachial nerve
(T2) innervates the skin of the medial upper arm and axilla.
Knowledge of brachial plexus anatomy and the derma­
tomes supplied (Figs. 4.2 & 4.3) enables selective regional
anesthesia.
Perineurial environment
The axillary sheath is the connective tissue surrounding the
neurovascular structures of the brachial plexus. It originates
as a continuation of the prevertebral fascia and joins the fascia
of the biceps and brachialis muscles distally. This connective
tissue extends inward, forming septa between components of
the plexus and creating fascial compartments for each nerve.2
Controversy exists regarding the ability of the septa to limit
the spread of local anesthetics within the sheath. Some inves­
tigators report that these fascial compartments limit the
  Access video content for this chapter online at expertconsult.com

97
Anatomy
Fig. 4.1  Brachial plexus anatomy.
from C4
C5
C5
C6
C6
C7
C7
C8
C8
T1
T1
Axillary nerve
LATERAL
POSTERIOR
MEDIAL
SUPERIOR
MIDDLE
INFERIOR
ROOTS
3 TRUNKS
3 CORDS
DIVISIONS
3 Ventral
3 Dorsal
TERMINAL BRANCHES
Radial nerve
Median nerve
Ulnar nerve
Radial nerve
!st rib
Median nerve
Ulnar nerve
Musculocutaneous nerve
Median cutaneous nerve of forearm
Median cutaneous nerve of arm
Long thoracic
nerve
Suprascapular
nerve
Subscapular nerve
Thoracodorsal nerve
Fig. 4.2  Upper extremity nerve innervation (arm pronated).
Axillary nerve
Radial nerve
Radial nerve
Median nerve
Supraclavicular nerve (cervical plexus)
Ulnar nerve
Musculocutaneous nerve
(lateral antebrachial cutaneous nerve)
(posterior
antebrachial
cutaneous
nerve)
(posterior
brachial
cutaneous
nerve)
Intercostobrachial cutaneous nerve
(inferior
lateral
cutaneous
nerve)
Median antebrachial
cutaneous nerve
Fig. 4.3  Upper extremity nerve innervation (arm supinated).
Axillary nerve
Radial nerve
(superficial branch)
Radial nerve
(inferior lateral brachial
cutaneous nerve)
Median nerve
Supraclavicular nerve (cervical plexus)
Ulnar nerve
(palmar digital branch)
(palmar branch)
Musculocutaneous nerve
(lateral antebrachial cutaneous nerve)
Intercostobrachial
and medial brachial
cutaneous nerve
Median antebrachial
cutaneous nerve

98
SECTION I
CHAPTER 4 • Anesthesia for upper extremity surgery
hydrophilic tail, and a chain linking the head and tail which
is either an amide or ester and determines the classification of
the type of LA. Alteration of the structure of the LA affects the
various actions of the LA itself and is important when making
the choice of which LA to use. For example, increasing the
alkyl substitution on the aromatic ring increases its lipid solu­
bility, thereby increasing its potency. Allergic reactions to local
anesthetics are more common with esters and rare with
amides.
Pharmacokinetics
Local anesthetics differ from other drugs because they are
directly delivered at their site of action. Efficacy depends on
the amount of LA that reaches the nerve and proximity to
the nerve. Diffusion of local anesthetic is dependent on the
amount of connective tissue and adipose tissue that is present
in the area of the block.
Toxicity
Local anesthetic toxicity has been a concern since its first use
in nerve blockade. Regardless of which local anesthetic is
injected, traditional methods have required large volumes for
successful regional anesthesia such as with brachial plexus
blockade or Bier blocks. Frequent aspiration and incremental
dosing are imperative, as is communication with the patient
to detect early signs of potential intravenous injection before
progression to signs and symptoms of toxicity. Factors such
as drug dose, rate of absorption, biotransformation, and
elimination of the drug from the circulation are determinants
of the plasma concentration of local anesthetics. Fortunately,
one of the benefits of ultrasound guidance in the use of
regional anesthesia has been the decreased need for large
volumes.13
High plasma levels may be a consequence of direct intra­
vascular injection, plasma absorption, and/or certain under­
lying medical conditions of the patient (i.e., hypoproteinemia
in renal or hepatic disease). Elevated intravascular levels of
LA may result in minor CNS symptoms such as dizziness,
ringing in the ears, and may proceed to more intense symp­
toms of loss of consciousness, and seizures. At even higher
levels, cardiac arrhythmias ensue, including complete cardio­
vascular collapse. Use of LA in regional anesthesia demands
an appreciation of these toxicities. Understanding agent-
specific toxic levels is vital – as much as the preparation for
these unintended events.
Adjuncts such as epinephrine affect absorption and elimi­
nation. The use of epinephrine as a marker of intravascular
injection is warranted in almost all situations. Exceptions
include those cases where the vasoconstriction resulting from
epinephrine may in fact compromise the blood flow to the
area.
Physicians must be prepared with monitors, emergency
drugs, and airway supplies to facilitate treatment of LA-related
toxicity. Toxicity related to LA can include but is not limited
to oxygen desaturation, hypotension, bradycardia, and sei­
zures. The extent of toxicity is determined by the specific
drug’s intrinsic properties as well as the plasma level of the
LA. The safety of LA is an essential aspect of regional anes­
thesia and is dependent on the skill of the physician, place­
ment of the needle, the drug utilized, and patient health. All
circumferential spread of local anesthetics and that injected
solutions spread longitudinally up and down the nerve and
remain compartmentalized. This concept provides a rational
explanation for the occurrence of a rapid and profound block
of one nerve, yet partial or absent block in other nerves during
brachial plexus blockade.3 Other investigators propose that
these septa are incomplete and form small bubble-like pockets
when solution is injected. They found that single injections of
dye solutions into the axillary sheath resulted in immediate
staining of median, radial, and ulnar nerves, despite the pres­
ence of septa. These data demonstrate that there are connec­
tions between compartments within the sheath, and may
explain why single injection techniques have success rates
comparable with multiple injection techniques during block­
ade of the brachial plexus.4
Microneuroanatomy
Peripheral nerves are composed of fascicles of individual
nerve fibers surrounded by endoneurium. Groups of fas­
cicles are contained within the epineurium. As the nerve
travels away from the spinal cord, fascicle numbers increase,
while fascicle size decreases.5 The nerve roots contain large
fascicles, demonstrating a monofascicular or oligofascicular
pattern, while a multifascicular pattern is found more dis­
tally.6,7 While the amount of neural tissue remains constant,
the amount of non-neural connective tissue increases from
proximal to distal. The ratio of neural to non-neural tissue
changes from 1 : 1 in the proximal plexus to 1 : 2 in the more
distal plexus.2,7 The presence of non-neural tissue may
explain why injections within the epineurium rarely result in
neural injury.6
Sonoanatomy
The shape and echogenicity of a nerve determine its ultra­
sound appearance. Structures that strongly reflect ultrasound
waves generate large signal intensities and appear white or
hyperechoic. In contrast, hypoechoic structures weakly reflect
ultrasound waves and appear darker.8 Peripheral nerves
show a mixture of hypoechoic and hyperechoic structures
constituting a typical “honeycomb” structure.9 Hypoechoic
structures seen with ultrasound correspond to neural tissue,
while hyperechoic areas correlate with connective tissue.10
Ultrasound imaging of the proximal brachial plexus usually
shows hypoechoic structures reflecting an oligofascicular
pattern. Distal brachial plexus structures display a more
hyperechoic, honeycomb appearance, reflecting a multifas­
cicular pattern.7
Pharmacology of local anesthetics
Local anesthetics (LA) make regional anesthesia possible by
preventing the propagation of nerve conduction and inhibit­
ing or relieving pain.11 LA are primarily weak bases that attach
to sites of the sodium channel in nerves and prevent the
movement of the sodium ion through the nerve pores, which
temporarily halts nerve conduction.12
Local anesthetics are classified as amides or esters, based
on the chemical structure. Most local anesthetics used in
regional anesthesia are amides (e.g., “-caines”). The structure
of a typical local anesthetic consists of a lipophilic head, a

99
Pharmacology of local anesthetics
have the distinct advantage as they often can outlast the
surgery and offer the greater benefits of postoperative pain
management.
Time to onset is also an important factor. Most of the time,
regional anesthesia is done prior to the surgery and a fast time
to onset is highly desirable. Each LA has its own time to onset
or latency. Various factors can shorten this latency, including
the addition of bicarbonate, higher dose, and needle location.
The recent use of ultrasound allows for a more precise needle
placement, which in turn allows for quicker onset.
The choice of local anesthetic affects the quality of the
block, time to onset, and duration of action (Table 4.2).15
Quicker onset generally leads to quicker clearance. Lidocaine
and mepivacaine, agents with intermediate duration, have
a short latency period which is further shortened by the
addition of bicarbonate as mentioned above. In comparison,
bupivacaine and ropivacaine, two long-acting agents used
commonly in regional anesthesia, have a longer latency
period, and are not able to mix with bicarbonate due to pre­
cipitation concerns. Some may consider mixing two agents
together to achieve the quicker onset effect and the longer
duration of anesthesia/analgesia. These mixtures can be
about 50 : 50; however, it can vary depending on the experi­
ence and training of the anesthesiologist. The toxicity of
mixtures are additive and the mixture does not lower the
overall toxicity.17
Another consideration is the differential blockade, as
nerves are blocked unequally and at different rates. Nerve
blockade proceeds in the following order: sympathetic nerves,
pin-prick sensation, touch, temperature, and finally motor.18
This is an important attribute of bupivacaine, as one can
provide improved analgesia without much motor blockade in
the postoperative period if an infusion is run at analgesic
doses. Optimally, an LA with sensory selectivity is desired.
of these factors must be considered when determining the
appropriate procedure and LA dose.14
Bupivacaine has been in use for many years and has the
highest cardiotoxicity potential due to its intrinsic properties.
Although the cardiac system is generally resistant to the
effects of LA, bupivacaine is the notable exception. An over­
dose is more likely to result in cardiovascular collapse com­
pared with other LA. This cardiac collapse is difficult to treat
traditionally with ACLS/CPR alone. Recent case studies have
demonstrated that IV infusion of Intralipid, an emulsified fat,
may be successful in ameliorating cardiotoxicity associated
with local anesthetics by acting as a “sink”.
Vasoconstrictors
With the addition of vasoconstrictors such as epinephrine or
phenylephrine to the LA anesthetic solution, the systemic
absorption rate of an LA can be decreased.14 The dose of
bupivacaine increases from 3.5 to 4.0 mg/kg. This action of
epinephrine is more significant with lidocaine as the upper
limit increases from 3.0 to 7.0 mg/kg. Vasoconstrictors allow
the physician to identify an intravascular injection sooner
rather than later, due to the development of tachycardia with
an intravascular injection.15 The block can be halted immedi­
ately, possibly preventing a more serious intravascular com­
plication. Vasoconstrictors result in decreased plasma uptake
and increased duration of local anesthetic effect.16
LA selection
The choice of a LA depends on toxicity (as discussed previ­
ously), duration of effect, and time to onset (Table 4.1).
Duration is important when considering surgical times
when the block is the primary anesthetic. In such instances,
the longer-acting agents such as ropivacaine or bupivacaine
Table 4.1  Commonly used agents in upper extremity regional anesthesia
Lidocaine
Most widely used local anesthetic
Prototype amide
Can be used in almost any peripheral block
1.5% or 2% with or without epinephrine is most commonly used for surgical anesthesia
Mepivacaine
Intermediate duration
Similar to lidocaine
Less vasodilation
Ineffective as topical agent
1.5% mepivacaine is the most commonly used agent in regional anesthesia
Bupivacaine
One of the most commonly used local anesthetics in regional and infiltration anesthesia
Long-acting
High quality sensory anesthesia relative to motor blockade
Most commonly used for epidural and spinal
Refractory cardiac arrest with 0.75% concentration. Interaction with cardiac Na+ channels “fast in, slow out”
Disruption of atrioventricular nodal conduction
Depression of myocardial contractility
Indirect effects mediated by CNS
Limitations on total dose of bupivacaine given
Ropivacaine
Developed due to cardiotoxicity related to bupivacaine
Long-acting
Slightly less potent than bupivacaine
Higher concentrations fastens its onset and density of block
Reduced CNS/CV toxicity compared to bupivacaine

100
SECTION I
CHAPTER 4 • Anesthesia for upper extremity surgery
Table 4.2  Comparative pharmacology and current use of local anesthetics
Classification
and compounds
pKa
Non-ionized
(%) at pH 7.4
Potencya
Max. dose (mg)
for infiltrationb
Duration after
infiltration (min)
Topical
Infiltration
Intravenous
regional
Peripheral
block
Epidural
Spinalc
Esters
Procaine
8.9
3
1
500
45–60
No
Yes
No
Yes
No
Yes
Chloroprocaine
8.7
5
2
600
30–60
No
Yes
No
Yes
Yes
Yes (?)
Tetracaine
8.5
7
8
−
−
Yes
No
No
No
No
Yes
Amides
Lidocaine
7.9
24
2
300
60–120
Yes
Yes
Yes
Yes
Yes
Yes (?)
Mepivacaine
7.6
39
2
300
90–180
No
Yes
No
Yes
Yes
Yes (?)
Prilocaine
7.9
24
2
400
60–120
No
Yes
Yes
Yes
Yes
Yes (?)
Bupivacaine,
levobupivacaine
8.1
17
8
150
240–480
No
Yes
No
Yes
Yes
Yes
Ropivacaine
8.1
17
6
200
240–480
No
Yes
No
Yes
Yes
Yes
aRelative potencies vary based on experimental model or route of administration.
bDosage should take into account the site of injection, use of a vasoconstrictor, and patient-related factors.
cUse of lidocaine, mepivacaine, prilocaine, and chloroprocaine for spinal anesthesia is controversial and evolving (see text).