together to flex the finger. However, their action alone would wind up virtually every muscle in the limb is active.
the interphalangeal before the metacarpophalangeal joints and the
finger would not move in a normal arc of flexion. This is precisely what The hand is opened from its relaxed balanced posture, e.g. when stretch-
happens in an ulnar nerve paralysis, in which the interossei and lum- ing out to reach an object. This motion is made up of extension of the
bricals are not functioning. These small (intrinsic) muscles have been distal interphalangeal, proximal interphalangeal and metacarpophalan-
described earlier in terms of their individual actions. For their role in geal joints. The hand is provided with an ingenious mechanism that
coordinated activity, it is sufficient to appreciate that their contribution allows this to happen. The laws of mechanics would suggest that one
changes the arc produced by the long flexors, increasing flexion at the motor would be required for every joint in a chain, together with some
metacarpophalangeal joint and reducing flexion at the proximal inter- sort of controlling mechanism to ensure that the chain of joints moved
phalangeal joint. All three joints are then angulated to the same degree together in a coordinated fashion. In the hand, this is achieved through
and the fingers form a normal arc of flexion. As the finger flexes, the an extensor apparatus that minimizes the number of motors required
long extensor tendons (extensor digitorum, extensor indicis and exten- for movement by allowing the muscles to act on more than one joint,
sor digiti minimi) aid the process by relaxing and allowing the extensor and by linking different levels in the mechanism so that the arc of
apparatus to glide distally on the dorsum of the phalanges. motion is controlled.
The tendons of extensor digitorum run distally over the metacarpal
As the fingers wind up to make a fist, the wrist tends to extend, particu- heads, forming the major component of the extensor apparatus. Exten-
larly when force is applied. This extension has a marked effect on the sor digitorum has no insertion into the proximal phalanx and, there-


excursion of the long flexor tendons. On its own, digital flexion would fore, exerts its extensor action on the metacarpophalangeal joint
require the long tendons to move proximally in their sheaths and the indirectly through more distal insertions. The first point of insertion is
flexor muscles in the forearm would shorten. Extension of the wrist at the base of the middle phalanx (‘central slip’, in clinical practice).
tends to produce a lengthening of the same muscles, which, in normal Acting at this insertion alone, extensor digitorum can extend both meta-
use, is almost enough to balance the shortening due to finger flexion; carpophalangeal and proximal interphalangeal joints together. The
the net effect is a very slight shortening (approximately 1 cm) of the interossei are also active in hand opening, since they will tend to
long flexors in the forearm. The wrist can, therefore, be seen as a mecha- increase extension of the proximal interphalangeal joint. There is, there-
nism for maximizing force because it allows the fingers to flex while fore, a range of possibilities. At one extreme, with no contribution from
maintaining the resting length of the extrinsic muscles near to the peak the interossei, the long extensor will exert all of its action at the meta-
of the force–length curve. It is, of course, possible to wind up the fingers carpophalangeal joint; this leads to full extension, and even hyperexten-
with the wrist held in a neutral position but the grip is somewhat sion, while the proximal interphalangeal joint remains flexed (the
weaker. With the wrist in full flexion, it is not possible to flex the fingers typical ‘intrinsic minus’, or claw hand, of ulnar nerve paralysis). At the
fully. other extreme, when the intrinsics act strongly together with extensor
Flexion of the fingers on gripping tends to result in a distal excursion digitorum, the proximal interphalangeal joint will extend completely
of the long extensors. However, this tendency is counteracted by dorsi- while the metacarpophalangeal joint remains flexed (‘intrinsic plus’
flexion of the wrist. The net effect is a very small proximal excursion of hand). Thus, the hand possesses, in the proximal part of the extensor


the long extensor tendons on gripping, mirroring the effect on the flexor apparatus, a variable mechanism that allows different amounts of rela-
surface. If the movement of the wrist is exaggerated so that the wrist is tive metacarpophalangeal or proximal interphalangeal joint motion.
a little flexed on opening the hand, and fully dorsiflexed on closing it,
the net excursion of long flexors and extensors is zero, i.e. this whole
movement sequence can be completed with the forearm flexor and
extensor muscles contracting isometrically.


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In contrast, the more distal part of the extensor apparatus acts as an
automatic or fixed mechanism that determines that the two inter-
phalangeal joints, proximal and distal, will move together. The lateral
slips of the extensor apparatus arise from extensor digitorum and pass
distally on either side of the central slip and thus over the proximal
interphalangeal joint; being further lateral, they are nearer the joint axis
because the dorsal surface curves away on each side. A helpful analogy
that has been suggested for this arrangement is to consider it as two
pulleys of different size on one axle. The central slip can be regarded as
a cord that passes over the larger wheel, and each lateral slip as a cord
that passes over the smaller wheel. Since these latter pulleys are smaller,
there is less longitudinal excursion for a given rotation of the wheel,
and this allows some of the excursion to be used for another function,
namely: extension at the distal joint. There is an additional mechanism
by which the lateral slips move laterally during flexion of the proximal
interphalangeal joint. The effect of this lateral movement is to reduce
further the distance between the lateral slips and the joint axis, thereby
reducing the amount of excursion at the proximal interphalangeal joint
still more and allowing more excursion at the distal joint. When the
hand flexes, this mechanical linkage system allows both interphalangeal
joints to flex together in a coordinated way.
The extensor expansion also receives contributions from the inter-
ossei and lumbricals, which approach the digits from the webs and join
the corresponding expansion in the proximal segment of the digit.
These muscles can, therefore, act on the extensor apparatus at two levels:
they can extend the proximal interphalangeal joint through fibres that
radiate towards the central slip, and they can act on the distal inter-
phalangeal joint through fibres that join the lateral slip.
Apart from the components of the extensor expansion that are con-
cerned with joint function, the whole structure requires additional
anchorage. This must be arranged in such a way that it is not displaced
from the underlying skeleton, yet it must not restrict longitudinal move-
ment. These difficult requirements are met by transverse retinacular
ligaments at the level of the joints, the transverse ligaments running to


relatively fixed attachment points in the region of the joint axis. As the
expansion glides backwards and forwards, the transverse fibres move
like bucket handles. Smooth gliding layers are required under the
expansion and retinacular ligaments to allow motion to occur without
friction.


Vascular supply
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50.1). Lateral inclinations of the first phalanx maximize the extent of 11
excursion of the circumduction arc. Opposition is a composite position 9
1
of the thumb achieved by circumduction of the first metacarpal, inter- 7
nal rotation of the thumb ray, and maximal extension of the metacarpo-
phalangeal and interphalangeal joints (see Video 50.1). Retroposition
is the opposite to opposition (see Video 50.1). Flexion and adduction
6
is the position of maximal transpalmar adduction of the first metacar- 3
8
pal; the metacarpophalangeal and interphalangeal joints are flexed and
the thumb is in contact with the palm (see Video 50.1).
2
Rotary movements occur during circumduction. The simple angular 5
movements described above combine with rotation about the long axis
10 4
of the metacarpal shaft. In opposition, the shaft must rotate medially
into pronation. In retroposition, the thumb must rotate laterally into
supination. Axial rotation of the thumb metacarpal is produced by
G
muscle activity (which moves the thumb through its arc of circumduc-
tion); the geometry of the articular surfaces of the trapeziometacarpal
Fig. 50.34 A digital subtraction macroangiogram between capillary and
joint; and tensile forces in the ligaments (which combine with forces
venular phases. A small arterial-venous malformation shown on the index
exerted by the muscles of opposition and retroposition to produce axial
finger is suitable for radiologically guided embolization (arrows). Key:
rotation). The stability of the first metacarpal is greatest after complete
1, ulnar artery; 2, radial artery; 3, deep palmar arch; 4, princeps pollicis
pronation in the position of full opposition, when the tension in the
artery; 5, arteria radialis indicis; 6, superficial palmar arch (incomplete);
ligaments, muscular contraction and joint congruence combine to
7, proper palmar digital artery (little finger); 8, common palmar digital
maximal effect.


artery; 9, basilic vein; 10, cephalic vein; 11, digital vein.
(A-F, H-K, continued online)
Position of rest
Pinch grip muscles
The hand has a well-recognized position of rest, with the wrist in exten- The muscles of pinch grip may be divided into lateral, medial and
sion and the digits in some degree of flexion. The precise position of intermediate subgroups. The lateral subgroup (opposition muscles)
the thumb in the position of rest appears to be rather variable. Typically, moves the first metacarpal into palmar abduction. The metacarpal shaft
it is considered as the midpoint between maximal palmar abduction rotates medially into pronation. Radial angulation at the metacar-
and maximal retroposition. In this position, the carpometacarpal joint pophalangeal joint increases the span of the hand. The metacar-
lies within 20° of radial abduction and 30° of palmar abduction; from pophalangeal joint is stabilized principally by extensor pollicis brevis
clinical observations, it seems that the metacarpophalangeal joint lies and flexor pollicis brevis. Flexion of the proximal and distal phalanges
within approximately 40° of flexion and the interphalangeal joint is controlled. Muscles of the medial subgroup (abductor pollicis brevis
between extension and 10° of flexion. and first dorsal interosseous) produce an approach of the first metacar-
pal towards the palm. Since they act with the lateral group, they have
Grips a strong controlling effect on the position and rotation of the first
metacarpal. The intermediate subgroup consists of flexor pollicis
longus, which flexes the interphalangeal or metacarpop halangeal joint.
From the position of rest, the tip of the thumb can approach the radial
Palpating the thenar eminence during tip and lateral pinch provides
aspect of the fingers without incurring axial rotation because the palmar
some appreciation of the action of the pinch grip muscles.
and dorsal trapeziometacarpal ligaments remain relaxed (see below).
From different positions of the arc of circumduction, numerous differ-
The paralysed hand
ent types of pinch grip are possible (see Video 50.1). In clinical practice,


these have been classified into two main types: tip pinch and lateral (or
key) pinch. Many forces contribute to these configurations. Available with the Gray’s Anatomy e-book
The thumb is activated by monoarticular muscles (abductor polli-
cis longus and opponens pollicis), biarticular muscles (extensor polli-
cis brevis, adductor pollicis, abductor pollicis brevis and flexor pollicis VASCULAR SUPPLY
brevis) and polyarticular muscles (extensor pollicis longus and flexor
pollicis longus). It appears, however, that even a monoarticular muscle
ARTERIES
can change posture in all three joints by altering the overall balance of
forces and it is, therefore, very difficult to attribute function to the
Anastomoses occur between the radial and ulnar arteries at the wrist
individual intrinsic muscles. However, the thumb muscles do seem to
(via the palmar and dorsal carpal arches) and in the hand (via the
provide two broad functions. They position the metacarpal, an activity
superficial and deep palmar arches), and between their digital and
automatically accompanied by rotation, and also control the axial sta-
metacarpal branches (Fig. 50.34; Wong and Higgins 2015).
bility of the skeleton of the thumb.
The thumb muscles may be classified into those used for retroposi-
Radial artery
tion, opposition and pinch grip.
Retroposition muscles At the wrist, the radial artery passes on to the dorsal aspect of the carpus
The muscles that bring about retroposition are extensor pollicis longus, between the lateral carpal ligament and the tendons of abductor pollicis
extensor pollicis brevis and abductor pollicis longus. As the thumb longus and extensor pollicis brevis (Fig. 50.35). It crosses the scaphoid
moves into retroposition, automatic axial rotation produces supination bone and trapezium (in the anatomical snuff-box), where again, its
of the first metacarpal. This is produced by the off-axis action of two pulsation is obvious; as it passes between the heads of the first dorsal


parallel, but oppositely directed, forces: one exerted by extensors pol- interosseous, it is crossed by the tendon of extensor pollicis longus.
licis longus and brevis, and the other by abductor pollicis longus and Between the thumb extensors, it is crossed by the start of the cephalic
the anterior oblique carpometacarpal ligament. vein and the branches of the radial nerve that pass to the thumb and
index finger (see Fig. 50.42). Occasionally, it gives off a distal superficial
Opposition muscles dorsal branch that crosses the radial extensor tendons at the wrist,
A succession of activity occurs in the thenar muscles during the move- together with the superficial radial nerve. Branches of the lateral cutane-
ment of opposition. Three subgroups of radial (abductor pollicis longus ous nerve of the forearm run along its distal part as it curves round the
and extensor pollicis brevis), central (abductor pollicis brevis and oppo- carpus.
nens pollicis) and ulnar (flexor pollicis brevis) muscles are involved. In the hand, the radial artery passes through the first interosseous
These forces act simultaneously but with different intensities, depend- space between the heads of the first dorsal interosseous and crosses the
ing on the situation of the thumb. As the thumb moves into opposition, palm. At first, it lies deep to the oblique head of adductor pollicis and
there is automatic axial rotation of the first metacarpal shaft to produce then passes between its oblique and transverse heads or through the
pronation. This is produced by the paired action of oppositely directed transverse head. At the fifth metacarpal base, it anastomoses with
forces: the opposition muscles provide one force, and the posterior the deep branch of the ulnar artery, completing the deep palmar arch
oblique carpometacarpal ligament provides the other. (Fig. 50.36).


Wrist and hand
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The wrist and hand may be paralysed by many conditions, the most
common of which are spinal cord, brachial plexus and peripheral nerve
injury or compression, poliomyelitis, cerebral palsy and leprosy. Each
of these will cause different patterns of paralysis and contracture. The
main deformities in the cerebral palsied hand are pronation of the
forearm, flexion of the wrist and fingers, and flexion–adduction of
the thumb. Flexion–adduction deformity of the thumb reflects an
imbalance between its intrinsic and extrinsic musculature – principally
powered by adductor pollicis, the first dorsal interosseous, flexor pol-
licis brevis and abductor pollicis brevis – which produces flexion,
adduction and lateral rotation of the carpometacarpal joint, flexion and
lateral rotation of the metacarpophalangeal joint and flexion of the
interphalangeal joint. In an attempt to counteract this, the patient tends
to hold the wrist in extreme flexion and ulnar deviation (Matev 1963).
In leprosy, the intrinsic muscles of the hand are paralysed. The meta-
carpophalangeal joints have no primary flexor but retain the powerful
extensor digitorum. The interphalangeal joints have no primary exten-
sor and rely on the long flexor to initiate movement. This results in four
main disabilities: the fingers cannot be extended fully at the inter-
phalangeal joints; abduction and adduction of the digits are lost; when
grasping an object, flexion begins at the terminal joints, closing the
fingers on themselves rather than on the palm; and the effective part of
the finger becomes the tip and nail rather than the pulp (Brand 1958).


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A B
C D
E F
H I
J K
Fig. 50.34 Hand digital subtraction macroangiogram. Predominant phases. A, B arterial phase; C, D, arteriolar phase; E, F capillary phase; H, I venular
phase; J, K venous phase. A small arterial-venous malformation shown on the index finger is suitable for radiologically guided embolization.


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Fig. 50.35 Superficial structures
of the left palm and wrist. See
also Figure 50.25B.
Flexor digitorum profundus
Flexor digitorum superficialis
Fibrous digital sheath
Arteria radialis indicis
First lumbrical
Palmar digital artery
First dorsal interosseous
Palmar digital nerve
Abductor digiti minimi
Variable palmar connection
between ulnar and median nerves
Flexor pollicis brevis Superficial palmar arch
Recurrent branch of
Flexor retinaculum
median nerve
Abductor pollicis brevis
Guyon's canal
Palmar cutaneous branch Ulnar nerve
of median nerve
Palmar cutaneous branch
Superficial branch of
of ulnar nerve
radial artery
Ulnar artery
Median nerve
Flexor carpi ulnaris
Palmaris longus
Flexor carpi radialis
Radial artery
Brachioradialis Flexor digitorum superficialis
Fig. 50.36 The deep palmar arch and
First palmar metacarpal its branches. Note that the palmar
artery digital arteries to the thumb have a
First dorsal interosseous separate origin from the superficial
palmar arch in this specimen (as
Adductor pollicis
Common palmar digital artery sometimes occurs). The arteria
Medial palmar digital
princeps pollicis is absent in this
artery of the thumb
Communication with specimen.
Lateral palmar digital dorsal metacarpal artery
artery of the thumb
Superficial palmar arch
Deep palmar arch
Flexor pollicis brevis
Deep palmar branch of
radial artery
Flexor retinaculum (cut) Guyon's canal
Abductor pollicis brevis
Ulnar artery
Superficial palmar branch
Radial artery


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Palmar carpal branch The palmar carpal branch arises near the oblique head of adductor pollicis lateral to the first palmar inter-
distal border of pronator quadratus (see Fig. 49.9B). It crosses the an- osseous. At the base of the proximal phalanx, deep to the tendon of
terior surface of the distal end of the radius, near the palmar carpal flexor pollicis longus, the artery divides into two branches that appear
surface, and passes medially to anastomose behind the long flexor between the medial and lateral attachments of the oblique head of
tendons with the palmar carpal branch of the ulnar artery. This trans- adductor pollicis and run along both sides of the thumb. On the palmar
verse anastomosis is joined by longitudinal branches from the anterior surface of the distal phalanx, the branches form a pollicial arch that
interosseous artery and recurrent branches from the deep palmar arch, supplies the skin and subcutaneous tissue. The arteria princeps pollicis
forming a cruciate palmar radiocarpal arch that supplies the carpal ar- is the usual nutrient of supply to the first metacarpal bone.
ticulations and bones by descending branches.
Arteria radialis indicis The arteria radialis indicis is often a proxi-
Superficial palmar branch The superficial palmar branch arises mal branch of the arteria princeps pollicis, or may arise from the super-
from the radial artery just before it curves round the carpus. It passes ficial arch or from the first dorsal metacarpal artery, or may even
through, and occasionally over, the thenar muscles, which it supplies, combine with the arteria princeps pollicis to form the first palmar
and usually anastomoses with the end of the ulnar artery to complete metacarpal artery. It descends between the first dorsal interosseous and
a superficial palmar arch (see Figs 50.35–50.36). transverse head of adductor pollicis, and runs along the lateral side of
the index finger to its tip (see Fig. 50.35). It anastomoses with the index


Dorsal carpal branch The dorsal carpal branch arises deep to the medial digital artery and with the arteria princeps pollicis and the
tendons of the thumb extensors. It runs medially across the dorsal superficial palmar arch at the distal border of the transverse head of
carpal surface under the tendons and anastomoses with the ulnar dorsal adductor pollicis.
carpal branch, and also with the anterior and posterior interosseous
arteries, to form a dorsal radiocarpal arch (see Figs 49.9A, 49.9C). The Deep palmar arch The deep palmar arch is formed by anastomosis
carpal arches are both close to bone and supply the distal epiphysial of the end of the radial artery with the deep palmar branch of the ulnar
parts of the radius and ulna. Three dorsal metacarpal arteries descend artery (see Figs 50.36, 50.34G, 49.9B). It crosses the bases of the meta-
from the dorsal intercarpal arch on the second to fourth dorsal interos- carpal bones and interossei, covered by the oblique head of adductor
sei, and bifurcate into dorsal digital branches to supply the adjacent pollicis, the tendons of the digital flexors and the lumbricals. In its
sides of all four fingers. concavity, running laterally, is the deep branch of the ulnar nerve.
Rarely, the arch may be incomplete.
First dorsal metacarpal artery The first dorsal metacarpal artery
arises from the radial artery just before it passes between the heads of Palmar metacarpal artery The three palmar metacarpal arteries
the first dorsal interosseous. It divides, almost at once, into two run distally from the convexity of the deep palmar arch on the interossei
branches that supply the adjacent sides of the thumb and index finger of the second to fourth spaces, and join the common digital branches
as far distally as the proximal interphalangeal joint. The radial side of of the superficial arch at the digital clefts (see Fig. 50.36). They supply
the thumb receives a branch direct from the radial artery proper. In nutrient branches to the medial four metacarpals.


most cases, the first dorsal metacarpal artery follows a fascial course
overlying the first dorsal interosseous and parallel to the second meta- Perforating branches Three perforating branches from the deep
carpal bone. Occasionally, it may follow an intramuscular course. Dis- palmar arch cross the second to fourth interosseous spaces between the
tally, it anastomoses with the dorsal branches of the radiopalmar heads of the corresponding dorsal interossei and anastomose with the
digital artery of the index finger over the proximal phalanx. dorsal metacarpal arteries.
Second, third and fourth dorsal metacarpal arteries The Recurrent branches Recurrent branches ascend proximally from
second to fourth dorsal metacarpal arteries arise from the dorsal carpal the deep palmar arch anterior to the carpus to supply the carpal bones
arch. Near their origins, they anastomose with the deep palmar arch by and intercarpal articulations. They end in the palmar carpal arch.
proximal perforating arteries and, near their bifurcation, with dorsal
perforating branches from the palmar metacarpal arteries that pass Ulnar artery
between the metacarpal necks. They also anastomose distally at the level
of the web spaces with dorsal perforating branches from the palmar At the wrist, the ulnar artery (see Figs 50.35–50.36) is covered by skin,
digital arteries from the superficial palmar arch. The third and fourth fasciae and palmaris brevis. It lies between the superficial and main
dorsal metacarpal arteries are much smaller than the first and second. parts of the flexor retinaculum, lateral to the ulnar nerve and
Cutaneous branches from the dorsal metacarpal arteries supply the pisiform.
dorsal skin as far distally as the proximal interphalangeal joint. At the
level of the neck of the second, third and fourth metacarpals, a direct Dorsal cutaneous branch A constant dorso-ulnar perforator vessel
cutaneous branch is given off that passes proximally and supplies an is given off distally. It arises 2–5 cm proximal to the pisiform and


area of skin between the two adjacent metacarpals (Fig. 50.37). accompanies the dorsal cutaneous branch of the ulnar nerve. It emerges
between flexor carpi ulnaris and extensor carpi ulnaris.
Arteria princeps pollicis The arteria princeps pollicis arises from
the radial artery as it turns into the palm to form the deep palmar arch. Palmar carpal branch The palmar carpal branch crosses the distal
It descends on the palmar aspect of the first metacarpal under the ulna deep to the tendons of flexor digitorum profundus and anastomo-
ses with the palmar carpal branch of the radial artery to make a palmar
radiocarpal arch.
Dorsal carpal branch The dorsal carpal branch arises just proximal
to the pisiform. It curves deep to the tendon of flexor carpi ulnaris to
reach the carpal dorsum, which it crosses laterally beneath the extensor
tendons. It anastomoses with the dorsal carpal branch of the radial
artery to complete the dorsal carpal arch. Near its origin, it sends a small
Direct cutaneous branch digital branch along the ulnar side of the fifth metacarpal to supply the
medial side of the dorsal surface of the fifth finger.
Dorsal metacarpal artery
Superficial palmar arch Deep palmar branch The deep palmar branch is often double. It
Dorsal carpal arch passes between abductor and flexor digiti minimi, through or deep to
Palmar metacarpal artery opponens digiti minimi, and anastomoses with the radial artery, com-
pleting the deep palmar arch. The deep palmar branch accompanies the
deep branch of the ulnar nerve.
Deep palmar arch
Superficial palmar arch
Fig. 50.37 Communication between the palmar and dorsal metacarpal
arteries and the direct cutaneous branch given off the dorsal metacarpal
artery, 0.5–1.0 cm proximal to the metacarpophalangeal joint: sagittal The superficial palmar arch is an anastomosis fed mainly by the ulnar
view. artery (see Figs 50.35–50.36). The latter enters the palm with the ulnar


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nerve, anterior to the flexor retinaculum and lateral to the pisiform. It geal dorsal arterial arcades anastomose with each other and with those
passes medial to the hook of the hamate, then curves laterally to form from the other side of the digit. The superficial arcade occurs at the level
an arch that is convex distally and level with a transverse line through of the proximal nail fold and is supplied primarily by a dorsal branch
the distal border of the fully extended base of the thumb. About one- from the palmar digital artery, which is given off at the level of the
third of superficial palmar arches are formed by the ulnar artery alone, middle phalanx. The proximal subungual arcade is at the level of the
a further third are completed by the superficial palmar branch of the lunula and is supplied by a terminal branch of the digital artery, which
radial artery, and a third by the arteria radialis indicis, or a branch of passes dorsally. The distal subungual arcade occurs more distally in the
either arteria princeps pollicis or the median artery. The superficial nail bed. It is supplied by a dorsal vessel that emerges from the point
palmar arch is covered by palmaris brevis and the palmar aponeurosis, of confluence of the ‘H’-shaped anastomosis between the terminal por-
and it is superficial to flexor digiti minimi, branches of the median tions of both digital arteries, and passes from volar to dorsal aspect of
nerve and the tendons of the long flexors and the lumbricals. the digit under the interosseous ligament connecting the proximal and
distal parts of the distal phalanx.
Common and proper palmar digital arteries Three common
palmar digital arteries arise from the convexity of the superficial palmar Variations The ulnar and radial arteries to the hand may occasionally
arch (see Fig. 50.36). They pass distally on the second to fourth lum- be supplemented by a median artery that contributes to, or supplies,
bricals, each joined by a corresponding palmar metacarpal artery from the superficial palmar plane and by the anterior interosseous artery,


the deep palmar arch, and divide into two proper palmar digital arter- which may make a contribution to the deep palmar plane.
ies. These run along the contiguous sides of all four fingers, dorsal to Rodriguez-Niedenführ et al (1999) have confirmed that the median
the digital nerves, between Grayson’s and Cleland’s ligaments, anasto- artery may persist in two different forms, palmar and antebrachial. The
mosing in the subcutaneous tissue of the fingertips and near the inter- palmar type arises from the junction of the ulnar artery and its common
phalangeal joints. Each digital artery has two dorsal branches that interosseous trunk; it is long and large, and reaches the palm, usually
anastomose with the dorsal digital arteries and supply the soft parts ending as the first or second common digital artery, or both. The ante-
dorsal to the middle and distal phalanges, including the matrices of the brachial type is slender and short, usually arising from the anterior
nails. The palmar digital artery for the medial side of the little finger interosseous artery and finishing in the forearm. These variations are
leaves the arch under palmaris brevis. Palmar digital arteries supply the seen in about 20% of individuals and tend to be unilateral.
metacarpophalangeal and interphalangeal joints and nutrient rami to Kleinert et al (1989) demonstrated by plethysmography that 5% of
the phalanges. They are the main digital supply because the dorsal hands have ulnar artery dominance in all digits, compared with 28%
digital arteries are minute. The origins of the palmar digital arteries of with complete radial digital dominance.
the thumb are quite variable. Both may arise from a single arteria prin-
ceps pollicis or they may arise separately from the superficial palmar Glomus tumours Glomus tumours are very painful tumours of the
arch. The ulnar digital artery may arise from the first dorsal metacarpal glomus bodies (small arteriovenous anastomoses involved in the regu-
artery. lation of peripheral skin temperature control (see Fig. 6.16)). They are
The terminal branches of the digital arteries contribute to a number often tiny and sometimes difficult to identify. These tumours typically


of vascular arcades that provide a rich vascular supply for the distal occur in the proximal nail fold/subungual regions of the fingertips in
elements of each digit (see Fig. 50.37; Fig. 50.38). Three distal phalan- association with the dorsal digital arterial arcades, although they can
occur anywhere. They are diagnosed by exquisite point tenderness
over the swelling, with reduction of tenderness when the finger is
exsanguinated.
VEINS
Superficial veins of the hand
Subungual arcades
Dorsal and palmar digital veins Dorsal digital veins pass along
Superficial arcades
the sides of the fingers, joined by oblique branches. They unite from
the adjacent sides of the digits into three dorsal metacarpal veins that
Terminal branch form a dorsal venous network over the metacarpus (Fig. 50.39). This is
joined laterally by a dorsal digital vein from the radial side of the index
finger and both dorsal digital veins of the thumb, and is prolonged
proximally as the cephalic vein. Medially, a dorsal digital vein from the
Middle branch ulnar side of the little finger joins the network, which ultimately drains
proximally into the basilic vein. A vein often connects the central parts
of the network to the cephalic vein near the mid-forearm. Palmar digital
Digital artery veins connect to their dorsal counterparts by oblique veins that pass
between metacarpal heads. They also drain to a plexus superficial to the
palmar aponeurosis, extending over both thenar and hypothenar
regions.
Cephalic vein The cephalic vein forms over the anatomical snuff-box
from the radial extremity of the dorsal venous plexus and runs proxi-
mally over the distal lateral aspect of the radius, where it is easily visible.
Its further course is described on pages 858 and 830.
Deep veins of the hand
Ungual spine
Superior and deep palmar venous arches Superficial and deep
Interosseous ligament
palmar venous arches accompany their arterial counterparts and receive
the corresponding branches; common palmar digital veins join the
superficial arch and palmar metacarpal veins join the deep arch.
Collateral ligament of
distal interphalangeal joint
Palmar and dorsal metacarpal veins Deep veins accompanying


the dorsal metacarpal arteries receive perforating branches from the
palmar metacarpal veins. They end in the radial veins and the dorsal
venous network over the metacarpus. This network is joined laterally
Fig. 50.38 Terminal vascular arcades over the distal phalanx. (With by a dorsal digital vein from the radial side of the index finger and by
permission from Flint MH 1956 Some observations on the vascular supply both digital veins of the thumb, and is prolonged proximally as the
of the nail bed and terminal segments of the fingers. BJPS 8:186–95.) cephalic vein.


innervation
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Muscular branch (motor or recurrent branch)
The muscular branch is short and thick, and arises from the lateral side
of the nerve; it may be the first palmar branch or a terminal branch that
arises level with the digital branches. It runs laterally, just distal to the
flexor retinaculum and with a slight recurrent curve beneath the part of
the palmar aponeurosis covering the thenar muscles (see Fig. 50.40A).
It turns round the distal border of the retinaculum to lie superficial to
flexor pollicis brevis, which it usually supplies, and either continues
superficial to the muscle or traverses it. It gives a branch to abductor
pollicis brevis that enters the medial edge of the muscle, and then passes
deep to it to supply opponens pollicis, entering its medial edge. Its
terminal part occasionally gives a branch to the first dorsal interosseous,
and may be its sole or partial supply. The muscular branch may arise
in the carpal tunnel and pierce the flexor retinaculum. Anomalies of
the median nerve occur in approximately 10% of patients undergoing
Accessory a carpal tunnel release. These branches usually arise from the ulnar side
cephalic vein of the nerve and may be motor or sensory.
Palmar digital branches
The median nerve usually divides into four or five digital branches (see
Figs 50.40A, 50.35). It often divides first into a lateral ramus, providing
digital branches to the thumb and the radial side of the index finger,
and a medial ramus, supplying digital branches to adjacent sides of the
index, middle and ring fingers. Other modes of termination can occur.
Digital branches are commonly arranged as follows. They pass dis-
tally, deep to the superficial palmar arch and its digital vessels, at first
Perforating veins anterior to the tendons of the long flexors. Two proper palmar digital
nerves, sometimes from a common stem, pass to the sides of the thumb;
the nerve supplying its radial side crosses in front of the tendon of flexor
Cephalic vein
pollicis longus. The proper palmar digital nerve to the lateral side of
the index finger also supplies the first lumbrical. Two common palmar


digital nerves pass distally between the tendons of the long flexors. The
Basilic vein lateral divides in the distal palm into two proper palmar digital nerves
that traverse adjacent sides of the index and middle finger. The medial
divides into two proper palmar digital nerves that supply adjacent sides
of the middle and ring fingers. The lateral common digital nerve sup-
plies the second lumbrical, and the medial receives a communicating
twig from the common palmar digital branch of the ulnar nerve and
may supply the third lumbrical. In the distal part of the palm, the digital
arteries pass deeply between the divisions of the digital nerves; the
Dorsal venous network nerves lie anterior to the arteries on the sides of the digits. The median
nerve usually supplies palmar cutaneous digital branches to the radial
three and a half digits (thumb, index, middle and the lateral side of the
ring); sometimes, the radial side of the ring finger is supplied by the
ulnar nerve. Occasionally, there is a communicating branch between
the common digital nerve to the middle and ring fingers (derived from
the median nerve) and the common digital nerve to the ring and little
fingers (derived from the ulnar nerve); this may explain variations in
Dorsal metacarpal veins sensory patterns that do not conform to the classic pattern.
The proper palmar digital nerves pass along the medial side of the
index finger and both sides of the middle and the lateral side of the
ring finger. They enter these digits in fat between slips of the palmar
aponeurosis. Together with the lumbricals and palmar digital arteries,
Dorsal digital veins
they pass dorsal to the superficial transverse metacarpal ligament and
ventral to the deep transverse metacarpal ligament. In the digits, the
nerves run distally beside the long flexor tendons (outside their fibrous
sheaths), level with the anterior phalangeal surfaces and anterior to the
digital arteries, between Grayson’s and Cleland’s ligaments. Each nerve
gives off several branches to the skin on the front and sides of the digit
and sends branches to the metacarpophalangeal and interphalangeal
joints.
The digital nerves supply the fibrous sheaths of the long flexor


Fig. 50.39 The veins of the dorsum of the hand. (Redrawn with
tendons, blood vessels (vasomotor) and sweat glands (sudomotor).
permission from Drake RL, Vogl AW, Mitchell A et al (eds), Gray’s Atlas of
Distal to the base of the distal phalanx, each digital nerve gives off a
Anatomy, Elsevier, Churchill Livingstone. Copyright 2008.)
branch that passes dorsally to the nail bed. The main nerve frequently
trifurcates to supply the pulp and skin of the terminal part of the digit.
Distal to the base of the proximal phalanx, each proper digital nerve
INNERVATION also gives off a dorsal branch to supply the skin over the back of the
middle and distal phalanges. The proper palmar digital nerves to the
thumb and the lateral side of the index finger emerge with the tendons
Median nerve
of the long flexors from under the lateral edge of the palmar aponeur-
osis. They are arranged in the digits as described above, except that, in
The median nerve proximal to the flexor retinaculum is lateral to the the thumb, small distal branches supply the skin on the back of the
tendons of flexor digitorum superficialis and lies between the tendons distal phalanx only.
of flexor carpi radialis and palmaris longus (Figs 50.40A–50.41). It
Other branches
passes under the retinaculum in the ‘carpal tunnel’, where it may be
compressed in the carpal tunnel syndrome (see Fig. 46.11). Distal to In addition to the branches of the median nerve described above,
the retinaculum, the nerve enlarges and flattens, and usually divides variable vasomotor branches supply the radial and ulnar arteries
into five or six branches; the mode and level of division are variable. and their branches. Some of the intercarpal, carpometacarpal and


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A
A5
C3
A4
Cleland's ligament C2
A3
C1
Grayson's ligament
A2
A1
First dorsal
interosseous
Adductor pollicis
Flexor pollicis brevis
Communicating branch between median and
ulnar palmar digital nerves (variable)
Recurrent branch of
median nerve Superficial branch of ulnar nerve
Deep branch of ulnar nerve
Guyon's canal
Flexor retinaculum
Palmar cutaneous branch of ulnar nerve
Palmar cutaneous branch of median nerve
Abductor pollicis brevis
Ulnar nerve
Median nerve Ulnar artery
Radial artery
B
Palmar digital branch of ulnar nerve
Branches of median nerve
Branches of radial nerve
Branches of ulnar nerve
Palmar digital branches of
median nerve
Dorsal digital branches of ulnar nerve Dorsal digital branches of
radial nerve
Palmar digital branch of
median nerve
Dorsal digital branch of
radial nerve
Dorsal branch of ulnar nerve
Branches of
superficial radial nerve
Posterior cutaneous nerve of
forearm
Fig. 50.40 The cutaneous nerves of the hand. A, Palmar aspect. The anular and cruciate pulleys are shown schematically in the ring finger. B, Dorsal
aspect.


Surface anatomy of the wrist and hand
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Antebrachial fascia Palmaris longus
Median nerve, palmar cutaneous branch
Flexor digitorum superficialis Median nerve
Flexor carpi radialis
Flexor carpi ulnaris
Flexor pollicis longus
Ulnar artery and nerve
Radial artery
Ulnar nerve, dorsal branch
Lateral cutaneous nerve of forearm
Pronator quadratus
Flexor digitorum profundus Cephalic vein
Sacciform recess of radio-ulnar joint Abductor pollicis longus
Ulna Superficial radial nerve
Extensor pollicis brevis
Extensor carpi ulnaris
Brachioradialis
Extensors carpi radialis
Radio-ulnar joint longus and brevis
Extensor digiti minimi Radius
Extensors indicis and digitorum Extensor pollicis longus
Extensor retinaculum Basilic vein
Fig. 50.41 A transverse section through the supinated left wrist at the level of the distal radio-ulnar joint, showing the muscle tendons (in grey) and their
synovial sheaths (in green). (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer.
Copyright 2013.)
intermetacarpal joints are said to be supplied by the median nerve or ends by supplying adductor pollicis, the first dorsal interosseous and,
its anterior interosseous branch; the precise details are uncertain. usually, flexor pollicis brevis.
The medial part of flexor digitorum profundus is supplied by the
Carpal tunnel syndrome
ulnar nerve, as are the third and fourth lumbricals, which are connected
Carpal tunnel syndrome is the most common entrapment mononeur- with the tendons of this part of the muscle. Similarly, the lateral part
opathy. It is caused by compression of the median nerve as it passes of flexor digitorum profundus and the first and second lumbricals are
through the fibro-osseous tunnel beneath the flexor retinaculum (see supplied by the median nerve. The third lumbrical is often supplied by
Fig. 50.28). both nerves. The deep terminal branch gives branches to some inter-


carpal, carpometacarpal and intermetacarpal joints; precise details are
Median nerve division at the wrist
uncertain. Vasomotor branches, arising in the forearm and hand, supply
the ulnar and palmar arteries.
Available with the Gray’s Anatomy e-book
Ulnar tunnel syndrome
Ulnar nerve Ulnar tunnel syndrome is an entrapment neuropathy of the ulnar nerve
as it passes through Guyon’s canal at the wrist.
At the wrist, the ulnar nerve passes under the superficial part of Ulnar nerve division at the wrist
the flexor retinaculum (in Guyon’s canal) with the ulnar artery, and
divides into superficial and deep terminal branches (see Fig. 50.5).
Available with the Gray’s Anatomy e-book
Dorsal branch
The dorsal branch arises approximately 5 cm proximal to the wrist (see Radial nerve
Fig. 49.23). It passes distally and dorsally, deep to flexor carpi ulnaris,
perforates the deep fascia, descends along the medial side of the back
Branches of the superficial branch of the radial nerve reach the hand
of the wrist and hand, and then divides into two, or often three, dorsal
by curving around the wrist over the tendons of abductor pollicis
digital nerves. The first supplies the medial side of the little finger; the
longus and extensor pollicis brevis, and dividing into dorsal digital
second, the adjacent sides of the little and ring fingers; while the third,
nerves (see Fig. 50.40B, Fig. 50.42). They usually communicate with
when present, supplies adjoining sides of the ring and middle fingers.
the posterior and lateral cutaneous nerves of the forearm on the dorsum
The latter may be replaced, wholly or partially, by a branch of the radial
of the hand.
nerve, which communicates with it on the dorsum of the hand (see Fig.
50.40). In the little finger, the dorsal digital nerves extend only to the Dorsal digital nerves
base of the distal phalanx; in the ring finger, they extend only to the
There are usually four or five small dorsal digital nerves. The first sup-
base of the middle phalanx. The most distal parts of the little finger and


plies the skin of the radial side of the thumb and the adjoining thenar
of the ulnar side of the ring finger are supplied by dorsal branches of
eminence, and communicates with branches of the lateral cutaneous
the proper palmar digital branches of the ulnar nerve. The most distal
nerve of the forearm. The second supplies the medial side of the thumb;
part of the lateral side of the ring finger is supplied by dorsal branches
the third, the lateral side of the index finger; the fourth, the adjoining
of the proper palmar digital branch of the median nerve.
sides of the index and middle fingers. The fifth communicates with a
Superficial and deep terminal branches ramus of the dorsal branch of the ulnar nerve and supplies the adjoin-
Superficial terminal branch ing sides of the middle and ring fingers, where it is frequently replaced
by the dorsal branch of the ulnar nerve. The digital nerves of the thumb
The superficial terminal branch supplies palmaris brevis and the medial
reach only to the root of the nail; those in the index finger, midway
palmar skin. It divides into two palmar digital nerves, which can be
along the middle phalanx; and those to the middle and the lateral part
palpated against the hook of the hamate bone. One supplies the medial
of the ring finger may reach no further than the proximal interphalan-
side of the little finger; the other (a common palmar digital nerve) sends
geal joints. The remaining distal dorsal areas of the skin in these digits
a branch to the median nerve and divides into two proper digital nerves
are typically supplied by palmar digital branches of the median and
to supply the adjoining sides of little and ring fingers. The proper digital
ulnar nerves. However, the superficial terminal branch of the radial
branches are distributed like those derived from the median nerve.
nerve may supply the whole dorsum of the hand.
deep terminal branch
The deep terminal branch accompanies the deep branch of the ulnar
SURFACE ANATOMY OF THE WRIST AND HAND
artery as it passes between abductor digiti minimi and flexor digiti
minimi, and then perforates opponens digiti minimi to follow the deep
palmar arch dorsal to the flexor tendons (see Fig. 50.40A ). At its origin,
Available with the Gray’s Anatomy e-book


it supplies the three short muscles of the little finger. As it crosses the
hand, it supplies the interossei and the third and fourth lumbricals. It See Video 50.2.


Wrist and hand
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The carpal tunnel may be narrowed by arthritic changes in the wrist Ulnar nerve division at the wrist paralyses all the intrinsic muscles of
joint, particularly from rheumatoid arthritis, and by soft tissue thicken- the hand (apart from the radial two lumbricals, abductor pollicis brevis,
ing, as may occur in myxoedema and acromegaly; it may also be associ- and part of flexor pollicis brevis and opponens pollicis). The intrinsic
ated with oedema, obesity or pregnancy. Usually, the condition is muscle action of flexing the metacarpophalangeal joint and extending
idiopathic. Normally, the median nerve slides smoothly in and out of the interphalangeal joints is lost. The unopposed action of the long
the carpal tunnel during flexion and extension of the wrist, but when extensors and flexors of the fingers cause clawing, with extension of the
the nerve is compressed, additional damage may be produced during metacarpophalangeal joints and flexion of the interphalangeal joints.
these movements. The dominant hand is usually affected first, probably The clawing is less intense in the index and middle fingers because their
because this hand is used more frequently and more vigorously. Typi- lumbricals are supplied by the median nerve. (For a detailed account
cally, the syndrome produces pain, paraesthesia and numbness in the of the hand posture adopted in ulnar nerve lesions, see Smith (2002).)
thumb, index, middle and medial side of the ring fingers, which is worse There is sensory loss over the little finger and the ulnar half of the ring
at night and on gripping objects. The palmar branch of the median finger. The skin over the ulnar aspect of the dorsum of the hand is
nerve is spared because it does not pass through the carpal tunnel. With spared because the dorsal branch of the ulnar nerve is given off approxi-
time, the compression leads to wasting and weakness of abductor pol- mately 5 cm proximal to the wrist joint. A combined median and ulnar
licis brevis. Treatment is usually surgical decompression of the nerve by nerve palsy at the wrist results in a full claw hand with thenar and


dividing the flexor retinaculum, either as an open procedure or with hypothenar flattening and thumb adduction and flexion (a simian
endoscopic assistance. The most common hazards of decompression hand).
are: inadequate decompression because of failure to divide the most The superficial cutaneous branches of the radial nerve are at risk of
distal part of the flexor retinaculum; damage to the motor, or palmar injury from any procedure or injury in their immediate vicinity. Inci-
cutaneous, or one or more terminal sensory branches; prolapse of the sions or injections in or around the radial border of the wrist are par-
nerve through the gap in the retinaculum; and damage to the superficial ticularly implicated. The resultant painful neuromata can prove to be
palmar arch causing haematoma, compression, pain and, ultimately, resistant to treatment.
fibrosis or even a late false aneurysm (Birch 2011). The distal ulnar nerve
and its branches may also be damaged.
Anatomical anomalies of the median nerve occur at the level of the FLEXOR/VOLAR SURFACE
carpal tunnel in up to 12% of hands. The most common are variations
in the course of the recurrent motor branch in relation to the flexor The wrist joint is identified between the distal ends of the radius and
retinaculum: transligamentous (23%), subligamentous (31%) or extra- ulna, and the proximal carpus, on flexion and extension of the wrist.
ligamentous (46%) (Kretschmer et al 2009). Damage may also occur The line of the wrist joint corresponds to a line, convex superiorly,
to the palmar cutaneous branch of the median nerve and to the super- joining the radial and ulnar styloid processes. Its position is also marked
ficial connections between the median and ulnar nerves (the so-called by the proximal of the two transverse anterior wrist creases (see Fig.
Berrettini branch), division of which will leave the patient with numb- 46.30A). The radial styloid process normally sits 1 cm distal to the ulnar
ness in the middle and ring fingers. Stancić et al (1999) noted that this styloid process. Alteration of this arrangement can indicate fracture.


connection was present in 81% of dissected hands and proposed that When the forearm is pronated, the head of the ulna forms a rounded
it should be regarded as a normal anatomical finding. surface elevation on the medial side of the posterior aspect of the wrist
(see Figs 46.29C, 46.30B), and the ulnar styloid process projects distally
Median nerve division at the wrist leads to paralysis of the lumbricals from its posteromedial aspect. The radial styloid process projects infe-
to the index and middle fingers and of the thenar muscles (apart from riorly from the distal radius along the lateral aspect of the wrist. The
flexor pollicis brevis and adductor pollicis), as well as loss of sensation posterior aspect of the lower end of the radius is partly obscured by the
to the thumb, index, middle and radial half of the ring fingers. The extensor tendons but is palpable. The prominent dorsal radial (Lister’s)
radial half of the hand becomes flattened as a result of wasting of the tubercle is both visible and palpable, and aligns with the web space
thenar muscles and the adducted posture of the thumb. Division of between digits 2 and 3 (see Fig. 46.30B). The tendon of extensor pollicis
the median nerve distal to the origin of its palmar cutaneous branch, longus in extensor compartment 3 sits medial to the tubercle, and the
which arises somewhere between 3 and 7 cm proximal to the proximal tendons of extensors carpi radialis longus and brevis sit lateral to the
edge of the flexor retinaculum and the distal transverse wrist crease, will tubercle in compartment 2.
leave the branch intact to supply the skin over the thenar eminence and Four of the carpal bones are palpable. The pisiform is both visible
radial side of the proximal part of the hand. Careful clinical examina- and palpable on the palmar aspect of the medial wrist at the base of
tion of the sensibility of the skin in this region should help to clarify the hypothenar eminence. It is often overlain by the distal wrist crease.
the level of the lesion. High division of the nerve (Ch. 49) will, as with It can be moved over the articular surface of the triquetrum when the


compressive lesions at this level, result in weakness of pronation of the wrist is passively flexed. The hook of the hamate lies approximately
forearm, flexion of the wrist and the lateral two fingers. 2.5 cm distal to the pisiform, in line with the ulnar border of the ring
Causes of compression at this site include a ganglion, trauma, and finger. It can be felt on deep palpation, and the superficial division of
proximity of aberrant or accessory muscles. The symptoms include pain the ulnar nerve can be rolled from side to side over the tip of the hook.
in the hand or forearm and sensory changes in the palmar aspect of the The tubercle of the scaphoid is situated at the base of the thenar emi-
little and ulnar half of the ring fingers; sensation on the ulnar aspect of nence, in line with the tendon of flexor carpi radialis and, in many
the dorsum of the hand is normal. In addition, there may be weakness individuals, forms a small, visible elevation. Immediately distal to it,
and wasting of the intrinsic muscles of the hand supplied by the ulnar but covered by the muscles of the thenar eminence, the tubercle of the
nerve, with clawing posture in extreme cases. trapezium can be identified on deep palpation.
Surgical treatment involves decompression of the nerve by division
of the roof of Guyon’s canal and removal of the causative lesion, such
as a ganglion. Ulnar tunnel syndrome can be difficult to distinguish
from more proximal causes of ulnar nerve compression, of which the
most common is entrapment of the nerve in cubital canal at the elbow
(Ch. 49). Sensory changes may be present more proximally and, in
severe cases, weakness may be noted in flexor carpi ulnaris and the ulnar
part of flexor digitorum profundus. In the absence of obvious clinical
indicators, local tenderness over the site of compression and nerve
conduction studies may aid diagnosis.


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HAND
Proximal to the wrist creases, the prominent tendon of flexor carpi
radialis can be seen and palpated when the wrist is flexed against resist-
ance (see Fig. 46.30A). The radial artery lies on its lateral side and The palmar skin is marked by a number of creases but they are of little
crosses the anterior margin of the expanded distal end of the radius, value as points of reference. Transverse skin creases cross the palmar
where it is palpable. It then passes posteriorly, deep to the tendons aspect of the fingers in three places: the most proximal crease sits at the
of abductor pollicis longus and extensor pollicis brevis, and enters junction of the digit with the palm and lies approximately 2 cm distal
the anatomical snuff-box, where its pulsations are palpable (see to the metacarpophalangeal joint; the intermediate crease sits opposite
Fig. 46.30C). the proximal interphalangeal joint; and the distal crease sits just proxi-
Palpation lateral to flexor carpi radialis, 3–4 cm proximal to the wrist mal to the distal interphalangeal joint.
crease, reveals the muscle belly of flexor pollicis longus (flexing and The first metacarpal is both visible and palpable on the dorsolateral
extending the thumb will confirm that the examining finger is correctly hand; its dorsal aspect forms the lateral border of the hand. The fleshy
placed). The area on the ulnar side of flexor carpi radialis tendon is elevation of the thenar eminence, produced by abductor and flexor
packed with functionally important structures. The median nerve is pollicis brevis overlying opponens pollicis, is located on the lateral
either covered by, or situated just lateral/radial to, the tendon of pal- palm (see Fig. 46.48A). The less prominent hypothenar eminence is
maris longus. The latter can be identified by gently pinching the tips of located on the medial palm and is formed by the comparable muscles
the digits together and partially flexing the wrist (see Fig. 46.30A). Near of the little finger. The medial aspect of the hypothenar eminence forms


to the wrist, the median nerve lies very close to the skin and can, there- the medial border of the hand.
fore, be injured by relatively superficial lacerations. When palmaris The dorsal aspects of the trapezium and of each of the metacarpal
longus is absent, only a thin covering of subcutaneous fat and deep bones are partially palpable around the margins of the corresponding
fascia separate skin and nerve. The four tendons of flexor digitorum extensor tendons. The heads of the metacarpal bones form the promi-
superficialis lie deep to the median nerve; the tendons to the middle nences of the knuckles and are most obvious during digit flexion. On
and ring fingers lie anterior to those for the index and little fingers as the dorsal hand, the metacarpophalangeal joint line forms a palpable
they pass deep to the flexor retinaculum, and can be felt and usually depression lateral to the digital extensor tendon, and alternating digit
seen to move during finger flexion/extension. Deeper still are the flexion/extension aids identification. The joint can be aspirated/injected
tendons of flexor digitorum profundus. The broad tendon of flexor carpi from this perspective. Palpation distal to the metacarpal head reveals
ulnaris is easily palpated passing to the pisiform on the ulnar side of the flared base of the corresponding proximal phalanx. The inter-
the anterior wrist; the ulnar nerve, artery and venae comitantes lie along phalangeal joints are palpable on the dorsal aspect of a flexed digit just
its lateral (radial) edge. Any sharp injury that cuts through the tendon distal to the prominences formed by the heads of the proximal and
usually has enough energy to sever the ulnar neurovascular bundle. middle phalanges.
The flexor retinaculum, and therefore the surface position of the
carpal tunnel, can be mapped according to its palpable bony attach-
ANATOMICAL SNUFF-BOX ments (see Fig. 46.30A). The distal border is concave inferiorly and is
marked by a curved line that joins the tubercle of the trapezium to the


When the thumb is fully extended, the depression of the anatomical hook of the hamate. Its proximal border is marked by a curved line,
snuff-box is seen on the lateral aspect of the wrist immediately distal concave superiorly, which joins the tubercle of the scaphoid to the pisi-
to the radial styloid process. The snuff-box is bounded on its anterola- form. Flexion of the wrist produces a number of transverse skin creases
teral (radial) side by the tendons of abductor pollicis longus (laterally) (usually two, sometimes three) at the wrist. The dominant, most distal,
and extensor pollicis brevis (immediately medial), and on its wrist crease normally sits distal to the lunate and overlies pisiform and
posteromedial/ulnar side by the tendon of extensor pollicis longus. the proximal edge of the flexor retinaculum. The carpal tunnel passes
Running a finger along extensor pollicis brevis enables palpation of the distal to this crease for 2.5–3 cm.
superficial radial nerve, which can be rolled from side to side on the The position of the superficial palmar arterial arch is indicated by a
tendon. The cephalic vein passes through the roof of the snuff-box, horizontal line approximately 4 cm long, drawn at the level of the fully
where it is visible and palpable, and the pulsation of the radial artery extended and partially abducted thumb (see Fig. 46.30A). A horizontal
can be palpated deeply on its floor. line, approximately 4 cm long and running from a point just distal to
Three bones are palpable distal to the radial styloid process along the hook of the hamate, indicates the position of the deep palmar arter-
the floor of the anatomical snuff-box: the convex, ovoid proximal artic- ial arch. The deep arch is located approximately 1 cm proximal to the
ular surface of the scaphoid (best palpated during alternating wrist superficial arch. The digital neurovascular bundles pass along the
abduction/adduction), the radial aspect of the trapezium and the medial and lateral sides of the dorsal and volar surfaces of the digits,
expanded base of the first metacarpal. The first carpometacarpal joint and can be anaesthetized in these positions via the web space.


forms a palpable depression distal to the trapezium. When wrist stabil-
ity is clinically assessed throughout its range of movements, the
scaphoid may be compressed bidigitally, between index finger and
thumb, along its oblique long axis between the tubercle and articular
surface. Similarly, the trapezium may be compressed between its tuber-
cle and radial aspect.
EXTENSOR/DORSAL SURFACE
The tendons located within the six extensor compartments of the wrist
are subcutaneous and palpable (see Fig. 46.30B). Compartment 1 (con-
taining abductor pollicis longus and extensor pollicis brevis) sits over
the lateral radius. Regional tenderness to palpation occurs in de Quer-
vain’s tenosynovitis. Compartments 2 (containing extensors carpi radia-
lis longus and brevis) and 3 (containing extensor pollicis longus) flank
the lateral and medial sides of the dorsal radial (Lister’s) tubercle,
respectively. Compartments 5 (containing extensor digiti minimi) and
6 (containing extensor carpi ulnaris) flank the posterior and medial
sides of the ulnar head, respectively. Compartment 4 (containing exten-
sors digitorum and indicis) sits between the ulnar head and compart-
ment 3. The tendons of extensors carpi radialis longus and brevis can
be identified on the dorsal carpus when the fist is clenched and relaxed.
The tendons of extensor digitorum are visible and palpable on the
dorsal hand with the fingers fully extended. The tendon of extensor
carpi ulnaris is palpable distal to the ulnar styloid as it crosses the wrist,
with the wrist in extension and adduction. The first dorsal interosseous
forms a visible fleshy mass on the lateral part of the dorsal hand
between the index finger and thumb, especially whilst abducting the
index finger against resistance.


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nOiTCES
Bonus e-book images and videos
Fig. 50.5 Guyon’s canal at the wrist. Fig. 50.22 Scapholunate dissociation. Video 50.1 Movements of the hand.
Fig. 50.21 The effect of axial loading on the Fig. 50.34 Cont’d Hand digital subtraction Video 50.2 Wrist block: surface anatomy.
rotatory movements of the bones of the macroangiogram. Predominant phases.
wrist.
Extensor carpi radialis longus Dorsal carpal branch of radial artery
Extensor pollicis longus Extensor retinaculum
Abductor pollicis Superficial radial
longus nerve
Extensor pollicis brevis Lateral cutaneous
nerve of forearm
Fig. 50.42 The radial side of the hand. Note the course of the terminal branches of the superficial radial nerve and the lateral cutaneous nerve of the
forearm. (Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag,
London.)
KEY REFERENCES
Abrams RA, Peterson M, Botte MJ 1994 Arthroscopic portals of the wrist: an A chapter describing the various ways in which surgeons and others can
anatomic study. J Hand Surg 19A:940–4. injure the peripheral nerves of the body. Essential reading for all orthopaedic
A review of the surface and intra-articular anatomy of the wrist, the surgeons.
technique of establishing a safe portal and the specific uses of the
Oehmke MJ, Podranski T, Klaus R et al 2009 The blood supply of the radiocarpal, metacarpal and special-use portals.
scaphoid bone. J Hand Surg 34E:351–7.
An KN 2007 Tendon excursion and gliding: clinical impacts from humble An anatomical study of 12 cadaver hands which demonstrates a variety of
concepts. J Biomech 40:713–18. vascular anastomoses around the scaphoid. It notes that a dorsal approach
Describes the biomechanics of the movement of tendons in their synovial to the scaphoid bone is possible as there is an available blood supply from
sheaths. the palmar circulation.


Birch R 2011 Iatrogenous injuries. In: Surgical Disorders of the Peripheral
Nerves, 2nd ed. London: Springer-Verlag; pp. 483–526.


Wrist and hand
894.e1
05
RETPAHC
REFERENCES
Abrams RA, Petersen M, Botte MJ 1994 Arthroscopic portals of the wrist: an Krishnamoorthy R, Karthikeyan G 2011 Degloving injuries of the hand.
anatomic study. J Hand Surg 19A:940–4. Indian J Plast Surg 44:227–36.
A review of the surface and intra-articular anatomy of the wrist, the Kupfer DM, Eaton C, Swanson S et al 1999 Ring avulsion injuries: a bio-
technique of establishing a safe portal and the specific uses of the mechanical study. J Hand Surg Am 24:1249–53.
radiocarpal, metacarpal and special-use portals.
Ladd AL, Weiss AP, Crisco JJ et al 2013 The thumb carpometacarpal joint:
An KN 2007 Tendon excursion and gliding: clinical impacts from humble anatomy, hormones, and biomechanics. Instr Course Lect 62:165–79.
concept. J Biomech 40:713–18. Lee LC, Zhang AY, Chong AK et al 2006 Expression of a novel gene, MafB,
Describes the biomechanics of the movement of tendons in their synovial in Dupuytren’s disease. J Hand Surg 31:211–18.
sheaths.
Ling RSM 1963 The genetic factor in Dupuytren’s disease. J Bone Joint Surg
Becker C, Gilbert A 1988 The ulnar flap – description and applications. Eur Br 45:709–18.
J Plast Surg 11:79–82. McDonald LS, Bavaro MF, Hofmeister EP et al 2011 Hand infections. J Hand
Birch R 2011 Iatrogenous injuries. In: Surgical Disorders of the Peripheral Surg Am 36A:1403–12.
Nerves, 2nd ed. London: Springer-Verlag; pp. 483–526. McFarlane RM 1974 Patterns of the diseased fascia in the fingers in
A chapter describing the various ways in which surgeons and others can Dupuytren’s contracture. Displacement of the neurovascular bundle.
injure the peripheral nerves of the body. Essential reading for all orthopaedic Plast Reconstr Surg 54:31–44.
surgeons.


McFarlane RM 1991 Dupuytren’s disease: relation to work and injury. J Hand
Brand PW 1958 Paralytic claw hand. J Bone Joint Surg 40B:618–32. Surg Am 16:775–9.
Brand PW 1985 Operations to restore muscle balance to the hand. In: Clini- McGrouther D 1982 The microanatomy of Dupuytren’s contracture. Hand
cal Mechanics of the Hand. Mosby: St Louis. 14:215–36.
Brooks D, Buntic RF, Kind GM et al 2007 Ring avulsion: injury pattern, Matev I 1963 Surgical treatment of spastic ‘thumb-in-palm’ deformity.
treatment, and outcome. Clin Plast Surg 34:187–96. J Bone Joint Surg 45B:703–8.
Compson JP 1998 The anatomy of acute scaphoid fractures. J Bone Joint Navarro A 1921 Luxaciones del carpo. An Fac Med 6:113–41.
Surg 80B:218–24. Oehmke MJ, Podranski T, Klaus R et al 2009 The blood supply of the
Costa H, Pinto A, Zenha H 2007 The posterior interosseous flap – a prime scaphoid bone. J Hand Surg 34E:351–7.
technique in hand reconstruction. The experience of 100 anatomical An anatomical study of 12 cadaver hands which demonstrates a variety of
dissections and 102 clinical cases. J Plast Reconstr Aesthet Surg 60: vascular anastomoses around the scaphoid. It notes that a dorsal approach
740–7. to the scaphoid bone is possible as there is an available blood supply from
Cross D, Matullo KS 2014 Kienböck disease. Orthop Clin North Am 45: the palmar circulation.
141–52. Ortiz JA Jr, Berger RA 1998 Compartment syndrome of the hand and wrist.
Descatha A, Jauffret P, Chastang JF et al 2011 Should we consider Dupuytren’s Hand Clin 14:405–18.
contracture as work-related? A review and meta-analysis of an old Petrie S, Collins J, Solomonow M et al 1997 Mechanoreceptors in the


debate. BMC Musculoskelet Disord 12:96. palmar wrist ligaments. J Bone Joint Surg Br 79-B:494–6.
de Smet L 2002 Pitfalls in wrist arthroscopy. Acta Orthop Belg 68:325–9. Rodriguez-Niedenführ M, Sanudo JR, Vazquez T et al 1999 Median artery
Doyle JR, Blythe WF 1975 The finger flexor tendon sheath and pulleys: revisited. J Anat 195:57–63.
anatomy and reconstruction. AAOS Symposium on Tendon Surgery in Sendher R, Ladd AL 2013 The scaphoid. Orthop Clin North Am 44:
the Hand. St Louis: Mosby, pp. 81–8. 107–20.
Eardley WG, Stewart MP 2010 Early management of ballistic hand trauma. Slutsky DJ 2002 Volar portals in wrist arthroscopy. J Am Soc Surg Hand
J Am Acad Orthop Surg 18:118–26. 2:225–32.
Echigo A, Aok M, Ishiai S et al 2008 The excursion of the median nerve Smith PJ 2002 Lister’s The Hand. Diagnosis and Indications, 4th ed.
during nerve gliding exercise: an observation with high-resolution ultra- Edinburgh: Elsevier, Churchill Livingstone.
sonography. J Hand Ther 21:221–8.
Stancić MF, Mićović V, Potocnjak M 1999 The anatomy of the Berrettini
Edelstein DM, Kardashian G, Lee SK 2008 Radial collateral ligament injuries branch: implications for carpal tunnel release. J Neurosurg 91:
of the thumb. J Hand Surg Am 33:760–70. 1027–30.
Edmunds JO 2011 Current concepts of the anatomy of the thumb trapezio- Taleisnik J 1976 The ligaments of the wrist. J Hand Surg Am 1:110–18.
metacarpal joint. J Hand Surg Am 36:170–82.
Tomita K, Berger EJ, Berger RA et al 2007 Distribution of nerve endings in


Gelberman RH, Menon J 1980 The vascularity of the scaphoid bone. J Hand the human dorsal radiocarpal ligament. J Hand Surg Am 32A:466–73.
Surg Am 5:508–13.
Urbaniak JR, Evans JP, Bright DS 1981 Microvascular management of ring
Horii E, An K-N, Linscheid RL et al 1993 Excursion of prime wrist tendons. avulsion injuries. J Hand Surg Am 6:25–30.
J Hand Surg Am 18A:83–90.
Wilgis ES, Murphy R 1986 The significance of longitudinal excursion in
Johnston HM 1907 Varying positions of the carpal bones in the different peripheral nerves. Hand Clin 2:761–6.
movements at the wrist. J Anat Physiol 41:109–12.
Wong VW, Higgins JP 2015 Interpretation of upper extremity arteriography
Kleinert JM, Fleming SG, Smith Abel C et al 1989 Radial and ulnar artery vascular anatomy and pathology. Hand Clin 31:121–34.
dominance in normal digits. J Hand Surg Am 14A:504–8.
Kretschmer T, Antoniadis G, Richter H-P et al 2009 Avoiding iatrogenic
nerve injury in endoscopic carpal tunnel release. Neurosurg Clin N Am
20:65–9.


COMMENTARY
Injuries of the supraclavicular
6.1
brachial plexus
Rolfe Birch
The closed traction lesion of the supraclavicular brachial plexus is and the level of rupture of the dura, vary. These patterns are outlined
amongst the worst of all peripheral nerve injuries because of the fre- in a classification by Bonney (Birch 2011a) and examples are illustrated
quent association with injury to the spinal cord and the usual complica- in Figures 6.1.4, 6.1.5.
tion of severe pain. There is one common element: the violent distraction Bonney (1954, 1959) showed that the neuronal cell bodies in the
of the forequarter from the head, neck and chest so that the angle dorsal root ganglion in preganglionic injuries remained alive and that
between the head and the shoulder is opened. One important physical conduction within their peripheral axons was maintained, even though
sign that illustrates this point is the presence of linear abrasions and the cell body was separated from the spinal cord (Figs 6.1.6, 6.1.7); the
bruising at the tip of the shoulder (Fig. 6.1.1). These are often injuries axon reflex is probably maintained by the unmyelinated C fibres.
of great violence and motor cyclists in high-speed accidents are particu-
larly at risk. Associated injuries to the head, spine, chest, abdomen,
pelvis, long bones and subclavian artery are common.
The most common site of nerve lesion lies within the spinal canal,
affecting the intradural segments of the spinal nerves. These injuries are
called preganglionic because the lesion lies between the dorsal root
ganglion and the spinal cord. This concept of pre- and postganglionic
injury, introduced by Bonney in 1954, is fundamental to diagnosis and
treatment. The preganglionic injury is the most common lesion because
the union of the ventral and dorsal roots is the weakest link in the long
chain between the central nervous system and the periphery. Postgan-
glionic rupture usually involves the ventral (anterior) primary ramus,
distal to the branching of the dorsal (posterior) primary ramus (see Figs


45.1, 45.7). In one series of 200 patients operated on between the years
2000 and 2004, 429 spinal nerves sustained preganglionic rupture, 223
CNS tissue
were postganglionic ruptures and the remaining 298 spinal nerves were
intact or recovering. The fifth and sixth cervical nerves are somewhat
protected by proximal branches to such nerves as the phrenic and long
thoracic, and also by the transverse radicular ligaments. The vulnerabil-
ity of C8 and T1 is enhanced by the increasing obliquity of the roots
in the spinal canal and the angulated course of T1.
Fig. 6.1.2 A transverse section of the tip of an avulsed dorsal root at C6
There are two types of preganglionic, intradural, injury: rupture
4 days after injury, showing a central avulsion. The tissue in the centre of
peripheral to the transitional zone and avulsion central to it (Figs 6.1.2,
the section is central nervous system (CNS) tissue, in which glial cells
6.1.3; see also Fig. 3.35). The former is more common (Schenker and
show post-traumatic lytic changes. Corpora amylacea are indicated by
Birch 2001). The extent of the displacement of the dorsal root ganglion, arrows. Toluidine blue stained resin section ×100. (Courtesy of the Editor
Journal of Bone and Joint Surgery (British), from Schenker and Birch
(2001).
Fig. 6.1.3 An avulsed ventral root of C6 4 days after injury, showing a
peripheral intradural rupture. The nerve tissue at the site of the rupture
Fig. 6.1.1 Linear abrasions in the neck indicate separation of the showed no central nervous system features. The tip is covered by
forequarter from the trunk. The abrasion at the tip of the shoulder marks organized blood clot and erythrocytes that interweave with fibrin strands.
the point of impact against a roadside kerb. Rupture of C5, preganglionic The myelinated fibres show early signs of Wallerian degeneration.


C6–T1. (Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Toluidine blue stained resin section ×200. (Courtesy of Rolfe Birch, all
Surgical Disorders of the Peripheral Nerve. 2nd edition, 2011. Springer- rights reserved, published in Birch R, Surgical Disorders of the Peripheral
e54 Verlag, London.) Nerve. 2nd edition, 2011. Springer-Verlag, London.)


Injuries of the supraclavicular brachial plexus
e55
1.6
YRATNEMMOC
Fig. 6.1.4 The fifth and sixth cervical nerves avulsed from
the spinal cord. The ventral root is easily distinguishable
from the dorsal rootlets. Note the dorsal root ganglion, the
dural sleeve merging into the epineurium, and the spinal
nerve itself. The small pieces of tissue on the proximal ends
of the dorsal rootlets (below) are probably portions of the
spinal cord. (Courtesy of Rolfe Birch, all rights reserved,
Phrenic nerve published in Birch R, Surgical Disorders of the Peripheral
Nerve. 2nd edition, 2011. Springer-Verlag, London.)
Dorsal root
ganglion C5
Dorsal root
ganglion C6
Ventral root C5
Ventral root C6
Dorsal roots C5
Dorsal roots C6
A
B
46.5 mm
Fig. 6.1.5 Ischaemia and conduction. A, A traction lesion of the brachial
plexus accompanied by rupture of the subclavian artery; there was a
weak pulse. At operation, 54 hours after injury, stimulation of the avulsed
ventral roots of C7, 8 and T1 evoked strong contraction in the relevant
muscles distally. This showed that there was neither critical ischaemia
within the limb nor a second, more distal, lesion. B, Strong
somatosensory evoked potentials were recorded through electrodes
placed over the scalp, by stimulation of the postganglionic ruptured
stumps of C5 and C6 (1). The dorsal root ganglia of C7, 8 and T1 (2) and
their ventral roots (3) are shown. An extensive repair was done. C, An
arteriogram showing the ruptured subclavian artery. (Courtesy of Rolfe
C Birch, all rights reserved, published in Birch R, Surgical Disorders of the
Peripheral Nerve. 2nd edition, 2011. Springer-Verlag, London.)
Bonney and Gilliatt (1958) recorded sensory action potentials from attempts to reattach the ruptured ventral root to the spinal cord (see


peripheral nerves in cases of preganglionic injury; the measurements of below).
persisting peripheral conduction stimulated a profound and lasting
interest in conduction in the central pathways. Intraoperative studies of
Diagnosis
motor and sensory conduction are essential in emergency or urgent
exploration of the brachial plexus. The demonstration that myelinated
afferent fibres pass through the ventral root in the human (Schenker It is important always to search for occult injuries to the head, chest
and Birch 2000) (Fig. 6.1.8) may be significant in recent successful and spine. Once the diagnosis of injury to the brachial plexus has been


INjuRIEs Of ThE supRAClAvICulAR bRAChIAl plExus
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6
NOITCEs
Fig. 6.1.6 A dorsal root ganglion 6 months after avulsion from the spinal
cord. The cell bodies are healthy and there are numerous myelinated
fibres. Solochrome cyanin ×960. (Courtesy of Rolfe Birch, all rights
reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve.
2nd edition, 2011. Springer-Verlag, London.)
Direct ascending tracts
Dorsal root Dorsal root
ganglion ganglion
Cells and
sensory
nerves A
B
Fig. 6.1.9 A–B, Intense, lightning-like pain was felt in the dermatomes of
Degenerate C5, 6 and 7 in this patient on the day of injury; these three nerves were
efferent avulsed from the spinal cord. (Courtesy of Rolfe Birch, all rights reserved,
Ventral horn cell and axon published in Birch R, Surgical Disorders of the Peripheral Nerve. 2nd
Afferent fibre in edition, 2011. Springer-Verlag, London.)
ventral root
Fig. 6.1.7 The nerve and roots detached from the spinal cord. Note the
intact dorsal root ganglion cell, with healthy axons in the detached parts made, it should be put to one side while a systematic and systemic
of the roots, and the degeneration of the efferent fibre in the ventral root. examination is made of the whole patient. Analysis, history and precise
(Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical
clinical examination usually permit an accurate diagnosis of the extent
Disorders of the Peripheral Nerve. 2nd edition, 2011. Springer-Verlag,
and the level of the neurological injury.
London.)
History An understanding of the axis of application of force to the
injured limb is very important. A description from witnesses or the
patient of the shoulder being violently arrested by an object – stone,
tree, kerb or vehicle – while the body is flying through the air confirms
that there has been violent stretching of the structures in the posterior
triangle of the neck.
Pain Severe pain within a paralysed and anaesthetic limb indicates very


serious injury to the spinal nerves. It may be constant, described as
crushing, burning or intense pins and needles, and is usually felt in the
forearm and hand. Two-thirds of conscious patients who developed
such pain did so on the day of injury. The superimposed shooting pain
coursing into the dermatome of a spinal nerve signifies preganglionic
injury to the nerve (Fig. 6.1.9). More than one-half of conscious
patients experienced this pain on the day of injury (Birch 2011b).
Inspection Inspection of the limb may reveal linear cuts and abra-
sions passing from the face to the shoulder, indicating distraction of
the limb when injury was sustained. Deep bruising is an important sign
of tearing of prevertebral muscle or even of the subclavian artery.
Increasing swelling in the posterior triangle indicates a collection of
spinal fluid, either from nerves avulsed from the spinal cord or from
an expanding haematoma, or both. A Horner (Bernard Horner) sign is
a strong indicator of preganglionic injury to C8 and T1 because of inter-
Fig. 6.1.8 Wallerian degeneration in the ventral root of the eighth cervical ruption of the rami between the spinal nerves and the stellate ganglion
nerve 6 weeks after avulsion from the spinal cord. A degenerate efferent (see Figs 46.16 and 16.13).
myelinated fibre (right) compared to a non-degenerate afferent myelinated
fibre (left). EM ×11115. (Courtesy of Rolfe Birch, all rights reserved, Sensory loss Sensory loss extending above the clavicle is a sign of
published in Birch R, Surgical Disorders of the Peripheral Nerve. 2nd preganglionic injury to at least the upper nerves of the brachial plexus
edition, 2011. Springer-Verlag, London.) (Figs 6.1.10–6.1.13).


Injuries of the supraclavicular brachial plexus
e57
1.6
YRATNEMMOC
Fig. 6.1.10 Sensory loss in a complete
preganglionic lesion of C4–T1 in two patients.
(Courtesy of Rolfe Birch, all rights reserved,
published in Birch R, Surgical Disorders of the
Peripheral Nerve. 2nd edition, 2011. Springer-Verlag,
London.)
B
A
Fig. 6.1.12 Sensory loss in a preganglionic lesion of C4, 5, 6, 7. (Courtesy
of Rolfe Birch, all rights reserved, published in Birch R, Surgical Disorders
of the Peripheral Nerve. 2nd edition, 2011. Springer-Verlag, London.)
patient that percussion in the posterior triangle of the neck may be
painful – at times, extremely so. The patient is asked to indicate the
region into which they experience radiation of intense ‘pins and
needles’. When these extend down the outer arm and proximal forearm,
then rupture of C5 is likely. When they extend to the lateral aspect of
the forearm and thumb, then a similar lesion of C6 may be anticipated.
Percussion over a rupture of C7 evokes sensations into the dorsum of
Fig. 6.1.11 Sensory loss in a preganglionic lesion of C5–T1. C4 innervates
the hand; that over a rupture of the lower trunk evokes sensations in
the skin of the outer aspect of the shoulder; T2 innervates the skin of the
the inner aspect of the forearm and little fingers.
inner aspect of the arm. (Courtesy of Rolfe Birch, all rights reserved,
It is difficult to overstate the significance of a strong positive Tinel’s
published in Birch R, Surgical Disorders of the Peripheral Nerve. 2nd
sign in detecting rupture of a spinal nerve within the posterior triangle:
edition, 2011. Springer-Verlag, London.)
the stronger the sign, the more likely the chances of finding a robust
stump. It should be emphasized that Tinel’s sign is detectable, in a
conscious patient, on the day of injury.
Muscle weakness Paralysis of serratus anterior and of the ipsilateral


hemidiaphragm shows that the lesion is in the most proximal segments Investigations Radiological and imaging studies confirm or modify
of C4–C7 and that these nerves are likely to have sustained pregangli- the clinical diagnosis, but they may also confirm or reveal associated
onic injury. injuries to the spinal column, the spinal cord and the chest. Plain radio-
graphs confirm elevation of the ipsilateral hemidiaphragm and may
Recognition of postganglionic rupture Tinel’s sign is most valu- show tilting of the cervical spine away from the side of injury, which
able in the early detection of ruptures. It is important to advise the is often associated with fracture or dislocation of the first rib. The


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NOITCEs
condition of roots and evidence of displacement or other abnormalities decrease in the severity of injury; the proportion of cases with complete
of the spinal cord are revealed by myelography: more precisely, by preganglionic injury of C5–T1 was 18.7% in the series reported by
computed tomographic (CT) myelography and, increasingly in current Rosson (1987); 17.3% in those operated on between 1989 and 1993;
practice, by magnetic resonance imaging (MRI). and less than 8% in patients operated on between 2000 and 2004
(Birch 2011a). However, the incidence of injury to the subclavian artery
Patterns of lesions in the operated cases remains steady over this time at about 10%.
Treatment
A survey of the incidence of these lesions in the UK, conducted through
the auspices of the British Orthopaedic Association, uncovered 328
patients admitted with complete or partial lesions in 1987 (Goldie and The direct object of treatment is rehabilitation. This entails the follow-
Coates 1992). The lesion was complete in 26.2% of patients; the sub- ing steps: provision of accurate diagnosis and prognosis; improvement
clavian artery was ruptured in 5.5%; there were other major injuries in of prognosis by repair of damaged nerves; relief of pain; palliation of
40%, and a wound in the neck in 5.5%. Table 6.1.1 sets out the patterns paralysis by custom-made orthoses and by musculotendinous transfers
of injury in 301 patients operated on in 1989–93. Complete lesions (Fig. 6.1.14); and assistance towards a return to original, appropriately
accounted for 141 of the cases; 52 patients sustained preganglionic modified or new work or study and to independent living.
injury to all five spinal nerves. Over the years, there has been a modest Operations should be undertaken as soon as the patient’s general
condition permits in cases where there is evidently a serious nerve
injury (Birch 2011a). There have been important improvements in out-
comes over the years. The possibility of reconnection of the avulsed


ventral roots to the spinal cord has been realized in a few carefully
selected cases (Fig. 6.1.15). The return of fluid and coordinated muscle
action, and of the biceps tendon jerk, suggests some regeneration into
the deep afferent pathway, perhaps through myelinated afferent fibres
in the ventral root.
Pain relief One of the most pleasing aspects of surgical endeavour
has been the finding that reinnervation of muscle is regularly successful
in improving pain and this is a strong indication for securing reinnerva-
tion of a limb, no matter how limited, in even the most severe injuries
(Berman et al 1996, Berman et al 1998, Kato et al 2006; see Birch
2011a, Birch 2011b, Birch 2011c).
Table 6.1.1 Patterns of injury in 301 consecutively operated supraclavicular lesions
(1989–93)
Pattern of injury Number of patients
Complete lesions: pre-and postganglionic injuries 141
Ruptures of upper nerves C5 (C6, 7) 83
Intradural ruptures of lower nerves (C6, 7, 8) T1
Ruptures of middle nerves (C6) C7 (C8) 5
Intradural above and below
Ruptures of lower nerves C8, T1 1
Intradural ruptures of upper nerves C5, 6, 7
Total intradural ruptures of C5–T1 52
Incomplete lesions: some roots intact 153
Damage C5, 6 (C7) 117
Recovering or intact (C7) C8, T1
Fig. 6.1.13 Sensory loss in a preganglionic lesion of C5. The area of
Damage C6, 7, 8 23
sensory loss is usually larger than that seen after rupture of the axillary
Recovering or intact C5, T1
(circumflex) nerve (see Fig. 48.2). (Courtesy of Rolfe Birch, all rights
Damage C7, 8, T1 13
reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve.
Recovering or intact C5, 6
2nd edition, 2011. Springer-Verlag, London.)
B
A


Fig. 6.1.14 A–B, A woman aged 28 at the time of injury with left-sided rupture of C5, C7, C8 and T1, preganglionic lesion C6. Function is shown at
96 months after repair: wrist extension was regained by transfer of flexor carpi ulnaris to extensor carpi radialis brevis. (Courtesy of Rolfe Birch, all rights
reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve. 2nd edition, 2011. Springer-Verlag, London.)


Injuries of the supraclavicular brachial plexus
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1.6
YRATNEMMOC
B
Fig. 6.1.15 A 23-year-old man with a left-sided preganglionic lesion of
C5–T1. Function is shown at the shoulder and elbow 11 years after
reimplantation of the ventral roots of C5, C6 and C7. (Courtesy of Rolfe
A Birch, all rights reserved, published in Birch R, Surgical Disorders of the
Peripheral Nerve. 2nd edition, 2011. Springer-Verlag, London.)
REFERENCES
Berman J, Anand P, Chen L et al 1996 Pain relief from preganglionic injury Bonney G, Gilliatt RW 1958 Sensory nerve conduction after traction lesion
to the brachial plexus by later intercostal transfer. J Bone Joint Surg of the brachial plexus. Proc Coll Med 51: 365–7.
78B:759–60. Goldie BS, Coates CJ 1992 Brachial plexus injuries – a survey of incidence
Berman JS, Birch R, Anand P 1998 Pain following human brachial plexus and referral pattern. J Hand Surg 17B:86–8.
injury with spinal cord root avulsion and the effect of surgery. Pain 75: Kato N, Htut M, Taggart M et al 2006 The effects of operative delay on the
199–207. relief of neuropathic pain after injury to the brachial plexus. J Bone Joint
Birch R 2011a The closed supraclavicular lesion. In: Surgical Disorders of the Surg 88B:756–9.
Peripheral Nerves, 2nd ed. London: Springer; Ch. 9, pp. 375–429. Rosson JW 1987 Disability following closed traction lesions of the brachial
Birch R 2011b Pain. In: Surgical Disorders of the Peripheral Nerves, 2nd ed. plexus sustained in motor cycle accidents. Hand Surg 12B:353–5.
London: Springer; Ch. 12, pp. 527–62. Schenker M, Birch R 2000 Intact myelinated fibres in biopsies of ventral


Birch R 2011c Rehabilitation. In: Surgical Disorders of the Peripheral Nerves, spinal roots after preganglionic traction injury to the brachial plexus. A
2nd ed. London: Springer; Ch. 14, pp. 607–30. proof that Sherrington’s ‘wrong way afferents’ exist in man? J Anat 197:
Bonney G 1954 The value of axon responses in determining the site of lesion 383–91.
in traction lesions of the brachial plexus. Brain 77:588–609. Schenker M, Birch R 2001 Diagnosis of the level of intradural rupture of
Bonney G 1959 Prognosis in traction lesions of the brachial plexus. J Bone the rootlets in traction lesions of the brachial plexus. J Bone Joint Surg
Joint Surg 41B:4–35. 83B:916–20.


COMMENTARY
Nerves at risk from
6.2
musculoskeletal injury
Rolfe Birch
The anatomical arrangements of some of the peripheral nerves make In the lower limb, nerve injuries are more common and more serious
them particularly vulnerable to damage from musculoskeletal injury. because of the greater forces involved in serious skeletal injuries. The
lumbosacral plexus is at risk in fracture dislocations of the sacroiliac
Fractures and dislocations joints, especially when fractures extend into the sacral foramina. The
sciatic nerve is damaged by posterior displacement of the femoral head
(see Fig. 78.11).
In the upper limb, the cords of the brachial plexus and the axillary
vessels pass in a space bounded by subscapularis (deep) and pectoralis
Tethering of nerves
minor (superficial). Anterior displacement of the humeral head or bone
fragments forces the nerves and vessels against the deep surface of pec-
toralis minor, which acts as a guillotine. Rupture of nerves and vessels In the upper limb, the axillary nerve runs in loose fatty tissue in its
is frequent in high-energy transfer injuries in younger adults and is course anterior to subscapularis. When it turns around that muscle, it
common in many lower-energy transfer injuries in the elderly (Fig. enters a quadrilateral tunnel formed by the union of the fasciae of
6.2.1). The proximity to bone of all three main nerves at the elbow subscapularis cranially, teres major caudally and coracobrachialis lat-
renders them vulnerable to skeletal injuries. erally, which surrounds the nerve and the posterior circumflex vessels.
A B
C
D
Fig. 6.2.1 A leaking aneurysm 20 weeks after fracture of the neck of the humerus in an 83-year-old woman. She made a good recovery after repair
of the defect. A, A radiograph on the day of injury. B, A radiograph at 18 weeks. C, A magnetic resonance imaging (MRI) scan at 18 weeks. D, An
angiogram on the day of operation. (Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve. 2nd
e60 edition, 2011. Springer-Verlag, London.)


Nerves at risk from musculoskeletal injury
e61
2.6
YRATNEMMOC
The neurovascular bundle curves around the inferior border of the flexor compartment of the forearm. The ulnar nerve is accompanied by
tendon of subscapularis, and passes over the superior border of the the ulnar artery in a discrete fascial compartment in the distal two-thirds
tendon of teres major, entering a near-horizontal tube. This arrange- of the forearm. The deep fibular nerve is accompanied by the anterior
ment puts the nerve at risk during anterior dislocation of the head of tibial artery, an end artery, throughout most of the anterior compart-
the humerus and the frequent complication of bleeding from the pos- ment of the leg; occlusion of this artery causes death of the nerves and
terior circumflex vessels, which strangles the nerve. The radial nerve is muscles of the anterior compartment. The femoral nerve is damaged
at risk from fractures of the shaft of the humerus between the two rela- by haematoma where it passes deep to the thick fascia over iliacus,
tively fixed points of the nerves to the lateral head of triceps and the and it is also at risk from bleeding into the femoral triangle (see
tunnel through the lateral intermuscular septum. Fig. 80.32; Fig. 6.2.4). The tibial nerve is accompanied by the pos-
In the lower limb, the common fibular nerve, which passes above or terior tibial artery in the distal half of the leg in a sheath of fascia similar
through piriformis in as many as 30% of cases, is tethered above in to the arrangements for the ulnar vessels and nerve (Fig. 6.2.5).
relation to piriformis and below at the neck of the fibula. The fascia
Collateral circulation
surrounding biceps femoris and its tendon sweeps around to embrace
the nerve; in dislocation of the knee, the muscle frequently avulses the The collateral circulation at the elbow depends on vessels that run with
tip of the head of the fibula and is displaced anteriorly, pulling the the three main nerves. This network may maintain an adequate supply
nerve with it. The deep fibular nerve passes rather acutely forwards to to the hand and the extensor muscles of the forearm after acute loss of


enter the anterior compartment of the leg. flow through the brachial artery if there is no associated fracture disloca-
Refer to Commentary 9.1 for further information on nerve tion. The situation is much worse if the ulnar or radial nerves, with their
biomechanics. accompanying vessels, are displaced into a fracture or compressed by
haematoma.
Fascial arrangements The collateral circulation at the knee is particularly poor. Acute
loss of flow through the popliteal artery, unless urgently restored,
invariably leads to extensive death of muscle and nerve, and often to
Sleeves of fascia surround main nerves and main vessels in some
amputation.
regions, an arrangement that predisposes the nerves to injury from
ischaemia and compression from bleeding. After the ventral primary
rami of C7, 8 and T1 enter the posterior triangle of the neck, they are
enclosed in quite a rigid space bounded posteriorly by the dorsal part
of the first rib, the transverse processes of the cervical vertebrae and the
fascia of levator scapulae. The nerves are embraced by scalenus anterior
and scalenus medius, both of which are invested in an unyielding fascia
(this is one envelope of the prevertebral fascia that also serves to bind
the phrenic nerve down to the anterior face of scalenus anterior). The
prevertebral fascia is particularly well developed anterior to the vertebral
column and at the base of the posterior triangle, where it envelops the
ventral primary rami of C7, 8 and T1, the phrenic nerve, the cervical
sympathetic chain, and subclavian and vertebral arteries. Infusion of
relatively large volumes of fluid, from 10 to 20 ml, deep to the prever-
tebral fascia, for the purpose of inducing regional block, may cause
tamponade of the radicular vessels that enter the spinal canal and con-
tribute to the anterior spinal artery (Fig. 6.2.2, see also Figs 45.11,
45.12).
The medial brachial fascial compartment extends from the axilla to
the elbow and is bounded by the tough medial intramuscular septum
and the axillary sheath. Bleeding into this compartment is responsible
for many infraclavicular plexopathies following regional block or frac-


ture dislocation of the shoulder (Fig. 6.2.3).
Neurovascular compartments
A
The anterior interosseous nerve and its accompanying artery may be
damaged by compression because of swelling in the deepest part of the
B
Fig. 6.2.3 Fracture of left proximal humerus, complicated by expanding
haematoma in a 63-year-old man. Two attempts to occlude the torn
posterior circumflex artery by interventional radiology failed. He was seen
at 8 weeks, by which time he was in right heart failure and in great pain;
he had a complete infraclavicular plexopathy on the left side. Six litres
of altered blood were removed from the axilla; his pain was relieved.
Recovery was particularly poor in the radial and median nerves. A, An
Fig. 6.2.2 The hands of an 11-year-old boy 7 years after anterior cord MR angiogram before operation. B, The left hand 4 years after operation.
infarction caused by interscalene block. (Courtesy of Rolfe Birch, all rights (Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical
reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve. Disorders of the Peripheral Nerve. 2nd edition, 2011. Springer-Verlag,
2nd edition, 2011. Springer-Verlag, London.) London.)