The palm and dorsum of the hand pdf - Upper limb

Basic Anatomy

which crosses in front of the

branch of the median nerve,

palmar cutaneous

9.38 and 9.55) is derived from the

supply to the skin of the palm (Figs.

sensory nerve

The

so improve the grip of the palm in holding a rounded object.

rugate the skin at the base of the hypothenar eminence and

superficial branch of the ulnar nerve. Its function is to cor

and is inserted into the skin of the palm. It is supplied by the

arises from the flexor retinaculum and palmar aponeurosis

(Fig. 9.55) is a small muscle that

palmaris brevis

The

the site of joints. Sweat glands are present in large numbers.

sites of skin movement, which are not necessarily placed at

fibrous bands. The skin shows many flexure creases at the

bound down to the underlying deep fascia by numerous

The skin of the palm of the hand is thick and hairless. It is

pollicis brevis (Fig. 9.65).

the tendons of the abductor pollicis longus and extensor

between the lateral collateral ligament of the wrist joint and

The radial artery reaches the back of the hand by passing

extends above and below the retinaculum.

compartment is provided with a synovial sheath, which

that contain the tendons of the extensor muscles. Each

underlying radius and ulna and form six compartments

Beneath the extensor retinaculum, fibrous septa pass to the

common compartment.

have separate synovial sheaths but share a

vis tendons

extensor pollicis bre

Abductor pollicis longus

lateral part of the posterior surface of the radius.

share a common synovial sheath and are situated on the

brevis tendons

Extensor carpi radialis longus

medial side of the dorsal tubercle of the radius.

winds around the

Extensor pollicis longus tendon

397

■

and

■

and the

The Palm of the Hand

Skin

Muscles of the Posterior Fascial Compartment of the Forearm

T A B L E 9 . 8

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Extensor carpi

radialis brevis

Lateral epicondyle of

humerus

Posterior surface

of base of third

metacarpal bone

Deep branch of

radial nerve

C7, 8

Extends and abducts

hand at wrist joint

Extensor

digitorum

Lateral epicondyle of

humerus

Middle and distal

phalanges of

medial four

fingers

Deep branch of

radial nerve

C7, 8

Extends fingers and hand

(see text for details)

Extensor digiti

minimi

Lateral epicondyle of

humerus

Extensor expansion

of little finger

Deep branch of

radial nerve

C7, 8

Extends metacarpal

phalangeal joint of little

finger

Extensor carpi

ulnaris

Lateral epicondyle of

humerus

Base of 5th

metacarpal bone

Deep branch of

radial nerve

C7, 8

Extends and adducts

hand at wrist joint

Anconeus

Lateral epicondyle of

humerus

Lateral surface

of olecranon

process of ulna

Radial nerve

C7, 8; T1

Extends elbow joint

Supinator

Lateral epicondyle of

humerus, anular

ligament of proximal

radioulnar joint, and

ulna

Neck and shaft of

radius

Deep branch of

radial nerve

C5, 6

Supination of forearm

Abductor pollicis

longus

Posterior surface of

shafts of radius and

ulna

Base of first

metacarpal bone

Deep branch of

radial nerve

C7, 8

Abducts and extends

thumb

Extensor pollicis

brevis

Posterior surface of

shaft of radius

Base of proximal

phalanx of thumb

Deep branch of

radial nerve

C7, 8

Extends

metacarpophalangeal

joints of thumb

Extensor pollicis

longus

Posterior surface of

shaft of ulna

Base of distal

phalanx of thumb

Deep branch of

radial nerve

C7, 8

Extends distal phalanx of

thumb

Extensor indicis

Posterior surface of

shaft of ulna

Extensor expansion

of index finger

Deep branch of

radial nerve

C7, 8

Extends

metacarpophalangeal

joint of index finger

The predominant nerve root supply is indicated by boldface type.

398

CHAPTER 9

cialis and the flexor carpi radialis muscles (Fig. 9.54).

space between the flexor digitorum superfi

restricted

The median nerve passes beneath the flexor retinaculum

through the lateral part of the tunnel in its own synovial

The tendon of the flexor pollicis longus muscle runs

the tendons to enter them from the lateral side.

the lateral side (Fig. 9.54). This allows the arterial supply to

and profundus invaginate a common synovial sheath from

All eight tendons of the flexor digitorum superficialis

tendons.

cle are on the same plane and lie behind the superficialis

The tendons of the flexor digitorum profundus mus

become arranged on the same plane (Fig. 9.62).

der of the flexor retinaculum, the four tendons diverge and

of those to the index and little fingers. At the lower bor

rows, those to the middle and ring fingers lying in front

superficialis muscle are arranged in anterior and posterior

nerve. The four separate tendons of the flexor digitorum

through the tunnel and are accompanied by the median

The long flexor tendons to the fingers and thumb pass

by the flexor retinaculum (Fig. 9.54).

forms a bony gutter. The gutter is converted into a tunnel

The carpus is deeply concave on its anterior surface and

The Carpal Tunnel

and to protect the underlying tendons.

attachment to the overlying skin and so improve the grip

The function of the palmar aponeurosis is to give firm

page 404).

take part in the formation of the palmar fascial spaces (see

borders, fibrous septa pass posteriorly into the palm and

the hypothenar and thenar muscles. From each of these

rosis are continuous with the thinner deep fascia covering

The medial and lateral borders of the palmar aponeu

the deep transverse ligaments.

tendons and finally fuse with the fibrous flexor sheath and

deep band divides into two, which diverge around the flexor

the other passing deeply to the root of the finger; here each

into two bands, one passing superficially to the skin and

at the bases of the fingers into four slips. Each slip divides

gus tendon (Fig. 9.55). The base of the aponeurosis divides

retinaculum and receives the insertion of the palmaris lon

aponeurosis is attached to the distal border of the flexor

tral area of the palm (Fig. 9.55). The apex of the palmar

The palmar aponeurosis is triangular and occupies the cen

palmar aponeurosis.

(described on page XXX) and the

flexor retinaculum

The deep fascia of the wrist and palm is thickened to form

(Fig. 9.38).

superficial branch of the radial nerve

or the

lateral cutaneous nerve of the forearm

plied by the

The skin over the base of the thenar eminence is sup

(Fig. 9.54) and supplies the medial part of the palm.

latter nerve also crosses in front of the flexor retinaculum

palmar cutaneous branch of the ulnar nerve;

flexor retinaculum and supplies the lateral part of the palm,

The Upper Limb

and the

the

Deep Fascia

the

The Palmar Aponeurosis

sheath.

in a

Carpal Tunnel Syndrome

The carpal tunnel, formed by the concave anterior surface

of the carpal bones and closed by the flexor retinaculum, is

tightly packed with the long flexor tendons of the fingers, with

their surrounding synovial sheaths, and the median nerve

(Fig.

vial sheaths of the flexor tendons or arthritic changes in the

median nerve within the tunnel. The exact cause of the com

of the thenar muscles. It is produced by compression of the

a burning pain

9.54). Clinically, the syndrome consists of

or “pins and needles” along the distribution of the median

nerve to the lateral three and a half fingers and weakness

pression is difficult to determine, but thickening of the syno-

carpal bones are thought to be responsible in many cases.

As you would expect, no paresthesia occurs over the thenar

eminence because this area of skin is supplied by the palmar

cutaneous branch of the median nerve, which passes super-

ficially to the flexor retinaculum. The condition is dramatically

relieved by decompressing the tunnel by making a longitudinal

incision through the flexor retinaculum.

C L I N I C A L N O T E S

native treatment of injection of the enzyme collagenase into

are actually extended by the pressure of the fingers against

joints. The distal interphalangeal joints are not involved and

fingers results in flexion of the proximal interphalangeal

long-standing cases, the pull on the fibrous sheaths of these

condition involves the little finger in the same manner. In

palm, flexing it at the metacarpophalangeal joint. Later, the

near the root of the ring finger and draws that finger into the

tion and may eventually disable the hand. It commonly starts

Dupuytren’s Contracture

Dupuytren’s contracture is a localized thickening and con-

tracture of the palmar aponeurosis, which limits hand func-

the palm.

Surgical division of the fibrous bands followed by physio-

therapy to the hand is the usual form of treatment. The alter-

the contracted bands of fibrous tissue has been shown to

significantly reduce the contractures and improve mobility.

C L I N I C A L N O T E S

Fibrous Flexor Sheaths

the base of the distal phalanx. The sheath and the bones form a

whereas the distal end of the sheath is closed and is attached to

ges (Fig. 9.66). The proximal end of the fibrous sheath is open,

strong fibrous sheath that is attached to the sides of the phalan

acarpal to the base of the distal phalanx, is provided with a

The anterior surface of each finger, from the head of the met-

blind tunnel in which the flexor

ns of the finger lie.

tendo

Basic Anatomy

mesentery and convey blood vessels to the tendons.

rior surface of the phalanges (Fig. 9.63). They resemble a

synovial membrane that connect the tendons to the ante

are small vascular folds of

brevia

vincula longa

The

of subjects.

at the level of the wrist in about 50%

ulnar bursa)

cialis and profundus tendons (sometimes referred to as

cates with the common synovial sheath of the superfi

communi

radial bursa)

(sometimes referred to as the

The synovial sheath of the flexor pollicis longus

retinaculum and the fibrous flexor sheaths.

smoothly, with a minimum of friction, beneath the flexor

the thumb. These sheaths allow the long tendons to move

gus tendon has its own synovial sheath that passes into

as they enter the fingers. The flexor pollicis lon

sheaths

digital synovial

the middle, and the ring fingers acquire

and the distal ends of the long flexor tendons of the index,

of the sheath stops abruptly on the middle of the palm,

ruption on the tendons of the little finger. The lateral part

part of this common sheath extends distally without inter

vial sheath from the lateral side (Fig. 9.54). The medial

cialis and profundus muscles invaginate a common syno

In the hand, the tendons of the flexor digitorum superfi

lax over the joints.

The fibrous sheath is thick over the phalanges but thin and

flexor digitorum superficialis and profundus (Fig. 9.66).

medial fingers, the tunnel is occupied by the tendons of the

don of the flexor pollicis longus. In the case of the four

In the thumb, the osteofibrous tunnel contains the ten

399

Synovial Flexor Sheaths

-
-

the

and

fibrous flexor sheath

digital synovial sheath opened
to show flexor tendons

digital synovial sheath

common flexor synovial sheath (ulnar bursa)

flexor retinaculum

flexor digitorum superficialis

flexor pollicis longus

flexor carpi radialis

synovial sheath for flexor carpi radialis

digital artery

synovial
sheath

skin

fibrous flexor sheath

flexor digitorum superficialis

palmar digital nerve

flexor digitorum profundus

dorsal digital nerve

dorsal extensor expansion

proximal phalanx

synovial sheath for flexor pollicis
longus (radial bursa)

insertion of flexor digitorum profundus

FIGURE 9.66

or synovial sheaths. Cross section of a finger is also

Anterior view of the palm of the hand showing the flex

shown.

Tenosynovitis of the Synovial Sheaths of the Flexor

with pus; the finger is held semiflexed and is swollen. Any

point of a needle or thorn. Rarely, the sheath may become

Tendons

Tenosynovitis is an infection of a synovial sheath. It most com-

monly results from the introduction of bacteria into a sheath

through a small penetrating wound, such as that made by the

infected by extension of a pulp-space infection.

Infection of a digital sheath results in distention of the sheath

attempt to extend the finger is accompanied by extreme pain

C L I N I C A L N O T E S

(continued)

400

CHAPTER 9

phalanx (Fig. 9.63).

inserted into the anterior surface of the base of the distal

of the superficialis tendon, continues downward, to be

digitorum profundus, having passed through the division

borders of the middle phalanx. Each tendon of the flexor

at once into two further slips, which are attached to the

superficialis tendon, having united again, divides almost

partial decussation of the fibers takes place (Fig. 9.63). The

tendon and meet on its deep or posterior surface, where

divides into two halves, which pass around the profundus

the fibrous flexor sheath; opposite the proximal phalanx it

Each tendon of the flexor digitorum superficialis enters

Insertion of the Long Flexor Tendons

The Upper Limb

The situation can be relieved surgically by incising the fibrous

fibrous flexor sheath anterior to the metacarpophalangeal

the long flexor tendons that catches on a narrowing of the

It is caused by the presence of a localized swelling of one of

ping when a patient is asked to flex and extend the fingers.

Trigger Finger

In trigger finger, there is a palpable and even audible snap-

joint. It may take place either in flexion or in extension. A simi-

lar condition occurring in the thumb is called trigger thumb.

flexor sheath.

C L I N I C A L N O T E S

Small Muscles of the Hand

are described in Table 9.9.

muscles are seen in Figures 9.55, 9.67, 9.68, and 9.69 and

the thumb, and the short muscles of the little finger. The

interossei muscles, the short muscles of

muscles, the eight

The small muscles of the hand include the four lumbrical

because the distended sheath is stretched. As the inflammatory

cula longa and brevia (Fig. 9.63). Rupture or later severe scarring

process continues, the pressure within the sheath rises and may

compress the blood supply to the tendons that travel in the vin-

of the tendons may follow.

A further increase in pressure can cause the sheath to rupture

at its proximal end. Anatomically, the digital sheath of the index

finger is related to the thenar space, whereas that of the ring

finger is related to the midpalmar space. The sheath for the

It restores the thumb to its anatomic position, which is flush

of the abducted thumb in the anteroposterior plane.

This movement can be defined as a movement backward

Adduction of the Thumb

pophalangeal joint.

takes place at the carpometacarpal joint and the metacar

forward of the thumb in the anteroposterior plane. It

Abduction of the thumb may be defined as a movement

Abduction of the Thumb

metacarpal bone at the carpometacarpal joint.

a small amount of abduction and medial rotation of the

the carpometacarpal and metacarpophalangeal joints and

up objects. This complex movement involves a flexion of

form one claw in the pincer-like action used for picking

gers. It is an important muscle and enables the thumb to

contact with the palmar surface of the tips of the other fin

the palmar surface of the tip of the thumb may come into

the thumb medially and forward across the palm so that

It should be noted that the opponens pollicis muscle pulls

Opposition of the Thumb

thenar eminence.

three of these muscles form the

the adductor pollicis (Figs. 9.59, 9.62, and 9.67). The first

brevis, the flexor pollicis brevis, the opponens pollicis, and

The short muscles of the thumb are the abductor pollicis

of the forearm between the flexor digitorum profundus ante

Should such an infection be neglected, pus may burst through

These relationships explain how infection can extend from the

middle finger is related to both the thenar and midpalmar spaces.

digital synovial sheaths and involve the palmar fascial spaces.

In the case of infection of the digital sheaths of the little fin-

ger and thumb, the ulnar and radial bursae are quickly involved.

the proximal ends of these bursae and enter the fascial space

riorly and the pronator quadratus and the interosseous mem-

brane posteriorly. This fascial space in the forearm is commonly

referred to clinically as the space of Parona.

Short Muscles of the Thumb

with the palm. The adductor pollicis is the muscle that, in

pincers grip of the thumb. Adduction of the thumb occurs

pollicis muscles, is largely responsible for the power of the

association with the flexor pollicis longus and the opponens

at the carpometacarpal and at the

ophalangeal

metacarp

The opponens digiti minimi muscle is only capable of rotat

Opposition of the Little Finger

(Figs 9.59, 9.62, and 9.67).

nence

hypothenar emi

digiti minimi, which together form the

minimi, the flexor digiti minimi brevis, and the opponens

The short muscles of the little finger are the abductor digiti

joint.

Short Muscles of the Little Finger

ing the fifth metacarpal bone to a slight degree.

ver,

Howe

mar muscles. Some authors describe only three palmar interossei

There are eight interossei, consisting of four dorsal and four pal-

and state that the first palmar interosseous is in reality a second
head to the flexor pollicis brevis: others believe that it is part of the
adductor pollicis muscle.

Basic Anatomy

401

second dorsal interosseous

third palmar interosseous

third dorsal interosseous

fourth dorsal interosseous

fourth palmar interosseous

deep palmar arch

opponens digiti minimi

abductor digiti minimi

ulnar artery and nerve

flexor retinaculum

flexor carpi radialis

radial artery

first palmar interosseous

flexor pollicis brevis

sesamoid bones

adductor pollicis

first dorsal interosseous

second palmar interosseous

abductor pollicis longus

abductor pollicis brevis

FIGURE 9.68

Anterior view of the palm of the hand showing the deep palmar arch and the deep terminal branch of the ulnar

nerve. The interossei are also shown.

flexor digitorum profundus

flexor digitorum superficialis

palmar ligament of joint

deep transverse palmar ligament

palmar metacarpal artery

deep palmar arch

deep branch of ulnar nerve

opponens digiti minimi

flexor digiti minimi

abductor digiti minimi

ulnar artery and nerve

flexor carpi ulnaris

flexor digitorum profundus

flexor carpi radialis

flexor pollicis longus

radial artery

abductor pollicis longus

opponens pollicis

oblique head of

adductor pollicis

transverse head of

adductor pollicis

flexor pollicis longus

first dorsal interosseous

first lumbrical

flexor digitorum superficialis

fibrous flexor sheath

flexor pollicis brevis

abductor pollicis brevis

FIGURE 9.67

xor tendons have been removed from the palm, but their

Anterior view of the palm of the hand. The long fle

method of insertion into the fingers is shown.

402

CHAPTER 9

The Upper Limb

interosseous

extensor digitorum

palmar interossei

dorsal interossei

FIGURE 9.69

Origins and insertion of the palmar and the

also shown.

dorsal interossei muscles. The actions of these muscles are

Small Muscles of the Hand

T A B L E 9 . 9

radial artery to complete the deep palmar arch (Figs. 9.67

digiti minimi and the flexor digiti minimi, and joins the

of the flexor retinaculum, passes between the abductor

arises in front

deep branch of the ulnar artery

The

and pass to the fingers (Fig. 9.62).

arise from the convexity of the arch

digital arteries

Four

of the fully extended thumb.

of the arch lies across the palm, level with the distal border

side by one of the branches of the radial artery. The curve

long flexor tendons. The arch is completed on the lateral

laterally behind the palmar aponeurosis and in front of the

the ulnar artery (Fig. 9.62). On entering the palm, it curves

is a direct continuation of

superficial palmar arch

The

palmar arch.

branch and then continues into the palm as the superficial

the pisiform bone (Fig. 9.62). The artery gives off a deep

retinaculum on the lateral side of the ulnar nerve and

The ulnar artery enters the hand anterior to the flexor

Ulnar Artery

acarpal bone forward and cupping the palm.

carpal joint of the little finger, thereby pulling the fifth met

it assists the flexor digiti minimi in flexing the carpometa

expansion of each

dorsal extensor

little fingers and

index, ring, and

of thumb and

Proximal phalanges

Tendons of flexor

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Palmaris brevis

Flexor retinaculum,

palmar

aponeurosis

Skin of palm

Superficial branch

of ulnar nerve

C8; T1

Corrugates skin to

improve grip of palm

Lumbricals (4)

digitorum

profundus

Extensor expansion

of medial four

fingers

1st and 2nd,

(i.e., lateral two)

median nerve;

3rd and 4th

deep branch of

ulnar nerve

C8; T1

Flex

metacarpophalangeal

joints and extend

interphalangeal joints

of fingers except

thumb

Interossei (8)

Palmar (4)

First arises from base

of 1st metacarpal;

remaining three

from anterior

surface of shafts

of 2nd, 4th, and 5th

metacarpals

finger (Fig. 9.69)

Deep branch of

ulnar nerve

C8; T1

Palmar interossei adduct

fingers toward center

of third finger

Dorsal (4)

Contiguous sides

of shafts of

metacarpal bones

Proximal phalanges

of index,

middle, and

ring fingers and

dorsal extensor

expansion

(Fig. 9.69)

Deep branch of

ulnar nerve

C8; T1

Dorsal interossei abduct

fingers from center

of third finger; both

palmar and dorsal flex

metacarpophalangeal

joints and extend

interphalangeal joints

(continued)

-
-

Arteries of the Palm

and 9.68).

Basic Anatomy

lateral axillary nodes.

drain into the

and some

infraclavicular nodes,

vein; they drain into the

the hand ascends in vessels that accompany the cephalic

The lymph from the lateral side of

lateral axillary nodes.

and then ascend to drain into the

supratrochlear nodes

vessels that accompany the basilic vein; they drain into the

The lymph from the medial side of the hand ascends in

on the dorsum of the hand.

or pass around the medial and lateral borders to join vessels

that is drained by vessels that ascend in front of the forearm

sum of the hand. Lymph vessels on the palm form a plexus

reach the webs. From here, the vessels ascend onto the dor

The lymph vessels of the fingers pass along their borders to

Lymph Drainage of the Palm

ing corresponding tributaries.

nied by superficial and deep palmar venous arches, receiv

Superficial and deep palmar arterial arches are accompa

Veins of the Palm

sides of the thumb.

which divides into two and supplies the lateral and medial

arteria princeps pollicis,

side of the index finger, and the

which supplies the lateral

arteria radialis indicis,

off the

Immediately on entering the palm, the radial artery gives

Branches of the Radial Artery in the Palm

mar arch.

inferiorly, to join the digital branches of the superficial pal

take part in the anastomosis around the wrist joint, and

The deep palmar arch sends branches superiorly, which

the extended thumb.

curve of the arch lies at a level with the proximal border of

the medial side by the deep branch of the ulnar artery. The

and the interosseous muscles. The arch is completed on

long flexor tendons and in front of the metacarpal bones

radial artery (Fig. 9.68). It curves medially beneath the

is a direct continuation of the

deep palmar arch

The

arch (Figs. 9.67 and 9.68).

of the adductor pollicis and continues as the deep palmar

it curves medially between the oblique and transverse heads

interosseous muscle (see page 406). On entering the palm,

ond metacarpal bones and the two heads of the first dorsal

ing forward between the proximal ends of the first and sec

The radial artery leaves the dorsum of the hand by turn

Radial Artery

403

-
-

Small Muscles of the Hand (continued)

T A B L E 9 . 9

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Short Muscles of Thumb
Abductor pollicis

brevis

Scaphoid, trapezium,

flexor retinaculum

Base of proximal

phalanx of thumb

Median nerve

C8; T1

Abduction of thumb

Flexor pollicis

brevis

Flexor retinaculum

Base of proximal

phalanx of thumb

Median nerve

C8; T1

Flexes

metacarpophalangeal

joint of thumb

Opponens

pollicis

Flexor retinaculum

Shaft of metacarpal

bone of thumb

Median nerve

C8; T1

Pulls thumb medially and

forward across palm

Adductor pollicis

Oblique head; 2nd

and 3rd metacarpal

bones; transverse

head; 3rd

metacarpal bone

Base of proximal

phalanx of thumb

Deep branch of

ulnar nerve

C8; T1

Adduction of thumb

Short Muscles of Little Finger
Abductor digiti

minimi

Pisiform bone

Base of proximal

phalanx of little

finger

Deep branch of

ulnar nerve

C8; T1

Abducts little finger

Flexor digiti

minimi

Flexor retinaculum

Base of proximal

phalanx of little

finger

Deep branch of

ulnar nerve

C8; T1

Flexes little finger

Opponens digiti

minimi

Flexor retinaculum

Medial border fifth

metacarpal bone

Deep branch of

ulnar nerve

C8; T1

Pulls 5th metacarpal

forward as in cupping

the palm

The predominant nerve root supply is indicated by boldface type.

404

CHAPTER 9

of the

palmar cutaneous branch

Note also that the

plies the second lumbrical muscle.

dorsal aspect of each finger. One of these branches also sup

the lateral three and a half fingers and the distal half of the

supply the palmar aspect of

cutaneous branches

The

pollicis) and the 1st lumbrical muscle.

pollicis brevis, the flexor pollicis brevis, and the opponens

supplies the muscles of the thenar eminence (the abductor

one fingerbreadth distal to the tubercle of the scaphoid; it

the lower border of the flexor retinaculum and lies about

takes a recurrent course around

muscular branch

The

immediately divides into lateral and medial branches.

carpal tunnel.

the flexor retinaculum and through the

behind

The median nerve enters the palm by passing

Median Nerve

The Upper Limb

Nerves of the Palm

median nerve given off in the front of the forearm (Fig. 9.55)

one of the palmar spaces.

with connective tissue. Proximally, it is continuous with

the tendon of each lumbrical muscle and is normally filled

is a potential space surrounding

lumbrical canal

The

bones (Fig. 9.70).

of the interossei and the third, fourth, and fifth metacarpal

dons to the middle, ring, and little fingers. It lies in front

lumbrical muscles and lies posterior to the long flexor ten

contains the 2nd, 3rd, and 4th

midpalmar space

The

(Fig. 9.70).

index finger and in front of the adductor pollicis muscle

cle and lies posterior to the long flexor tendons to the

contains the first lumbrical mus

thenar space

The

canals (Fig. 9.70).

two spaces are continuous with the appropriate lumbrical

forearm by the walls of the carpal tunnel. Distally, the

the thenar and midpalmar spaces are closed off from the

which lies medial to the septum (Fig. 9.70). Proximally,

midpalmar space,

taining the thenar muscles), and the

must not be confused with the fascial compartment con

which lies lateral to the septum (and

thenar space,

middle fingers. This second septum divides the palm into

passes between the long flexor tendons of the index and

the third metacarpal bone (Fig. 9.70). Usually, the septum

tum passes obliquely backward to the anterior border of

border of the palmar aponeurosis, a second fibrous sep

compartment is unimportant clinically. From the lateral

partment containing the three hypothenar muscles; this

bone (Fig. 9.70). Medial to this septum is a fascial com

is attached to the anterior border of the 5th metacarpal

its medial border, a fibrous septum passes backward and

lower border of the flexor retinaculum (Fig. 9.55). From

The triangular palmar aponeurosis fans out from the

infection in the palm.

important clinically because they may limit the spread of

filled with loose connective tissue. Their boundaries are

Normally, the fascial spaces of the palm are potential spaces

medial part of the palm (Fig. 9.38).

retinaculum (Fig. 9.54) and supplies the skin over the

to the flexor

anterior

off in the front of the forearm crosses

of the ulnar nerve given

palmar cutaneous branch

The

licis muscle.

4th lumbrical muscles, and both heads of the adductor pol

It supplies all the palmar and dorsal interossei, the 3rd and

the flexor digiti minimi, and the opponens digiti minimi.

hypothenar eminence, namely, the abductor digiti minimi,

to the three muscles of the

muscular branches

It gives off

front of the metacarpal bones and interosseous muscles.

arch. The nerve lies behind the long flexor tendons and in

passes laterally within the concavity of the deep palmar

around the lower border of the hook of the hamate, and

(Fig. 9.67). It pierces the opponens digiti minimi, winds

the abductor digiti minimi and the flexor digiti minimi

The deep branch of the ulnar nerve runs backward between

Deep Branch of the Ulnar Nerve

finger.

It also supplies the distal half of the dorsal aspect of each

the adjacent sides of the little and ring fingers (Fig. 9.62).

the palmar aspect of the medial side of the little finger and

cutaneous branches

to the palmaris brevis and

branch

muscular

The nerve gives off the following branches: a

and symptoms.

may be compressed at this site, giving rise to clinical signs

the superficial part of the flexor retinaculum. The nerve

created by fibrous tissue derived from

tunnel of Guyon,

nerve and artery may lie in a fibro-osseous tunnel, the

and 9.62). The ulnar artery is on its lateral side. Here, the

pisiform bone and the hook of the hamate (Figs. 9.55

the palm, lying in the subcutaneous tissue between the

The superficial branch of the ulnar nerve descends into

Superficial Branch of the Ulnar Nerve

divides into a superficial and a deep terminal branch.

bone (Figs. 9.55 and 9.62). As it crosses the retinaculum, it

retinaculum alongside the lateral border of the pisiform

to the flexor

anterior

The ulnar nerve enters the palm

Ulnar Nerve

skin over the lateral part of the palm (Fig. 9.38).

to the flexor retinaculum and supplies the

anterior

crosses

Fascial Spaces of the Palm

the

Fascial Spaces of the Palm and Infection

The fascial spaces of the palm (Fig. 9.70) are clinically impor-

tant because they can become infected and distended with

pus as a result of the spread of infection in acute suppura-

tive tenosynovitis; rarely, they can become infected after pen-

etrating wounds such as falling on a dirty nail.

C L I N I C A L N O T E S

Basic Anatomy

405

midpalmar space

lumbrical canals

thenar space

epiphysis

diaphysis

periosteum

pulp space

fibrous septa

deep fascia

digital artery

synovial sheath surrounding tendons of

flexor digitorum superficialis and profundus

medial fibrous septum

muscles of hypothenar eminence

interossei
midpalmar space

oblique fibrous septum

transverse head of adductor pollicis

long flexor tendons to index finger

thenar space

metacarpal bone

lateral fibrous septum

muscles of thenar eminence

synovial sheath surrounding flexor pollicis longus

palmar aponeurosis

FIGURE 9.70

Palmar and pulp fascial spaces.

periosteum of the terminal phalanx just distal to the

The deep fascia of the pulp of each finger fuses with the

Pulp Space of the Fingers

insertion of the long flexor tendons and closes off a fascial

Through the pulp space, which is filled with fat, runs

septa, which pass from the deep fascia to the periosteum.

pulp space is subdivided by the presence of numerous

(Fig. 9.70). Each

pulp space

compartment known as the

the terminal branch of the digital artery that supplies
the diaphysis of the terminal phalanx. The epiphysis of
the distal phalanx receives its blood supply proximal to
the pulp space.

Pulp-Space Infection (Felon)

ally introduced into the space by pinpricks or sewing needles.

most often in the thumb and index finger. Bacteria are usu

Infection of such a space is common and serious, occurring

situated in front of the terminal phalanx of each finger (Fig. 9.70).

The pulp space of the fingers is a closed fascial compartment

C L I N I C A L N O T E S

Because each space is subdivided into numerous smaller com

ulnar nerve.

radial nerve and the posterior cutaneous branch of the

of the hand is derived from the superficial branch of the

to the skin on the dorsum

sensory nerve supply

The

mobile on the underlying tendons and bones.

The skin on the dorsum of the hand is thin, hairy, and freely

proximally located epiphysis of this bone is saved because it

the blood vessels could result in necrosis of the diaphysis. The

of the phalanx passes through the pulp space, and pressure on

phalanx can occur. In children, the blood supply to the diaphysis

infection is left without decompression, infection of the terminal

causes the pressure in the pulp space to quickly rise. If the

mulation of inflammatory exudate within these compartments

partments by fibrous septa, it is easily understood that the accu-

receives its arterial supply just proximal to the pulp space.

The close relationship of the proximal end of the pulp

space to the digital synovial sheath accounts for the involve-

ment of the sheath in the infectious process when the pulp-

space infection has been neglected.

The Dorsum of the Hand

Skin

406

CHAPTER 9

supplies the medial third of the dorsum of the hand

tendon, descends over the extensor retinaculum, and

winds around the ulna deep to the flexor carpi ulnaris

posterior cutaneous branch of the ulnar nerve

The

finger.

the ulnar nerve, also supplies the lateral side of the ring

variation. Frequently, a dorsal digital nerve, a branch of

hand and fingers supplied by the radial nerve is subject to

side of the ring finger. The area of skin on the back of the

the thumb, the index and middle fingers, and the lateral

It divides into several dorsal digital nerves that supply

lateral two thirds of the dorsum of the hand (Fig. 9.38).

descends over the extensor retinaculum, and supplies the

around the radius deep to the brachioradialis tendon,

winds

superficial branch of the radial nerve

The

The Upper Limb

(Fig. 9.38). It divides into several dorsal digital nerves

cal muscle on the lateral side (Fig. 9.63).

side and farther distally receives the tendon of the lumbri

insertion of the corresponding interosseous muscle on each

The dorsal extensor expansion receives the tendon of

(Fig. 9.63).

verge to be inserted into the base of the distal phalanx

which con

two lateral parts,

the middle phalanx, and

which is inserted into the base of

central part,

parts: a

phalangeal joint, the extensor expansion splits into three

(Figs. 9.56 and 9.57). Near the proximal inter

expansion

extensor

tendon joins the fascial expansion called the

On the posterior surface of each finger, the extensor

digiti minimi (Fig. 9.55).

joined on its medial side by the two tendons of the extensor

of the extensor indicis, and the tendon to the little finger is

to the index finger is joined on its medial side by the tendon

proximal to the heads of the metacarpal bones. The tendon

connect the tendons to the little, ring, and middle fingers,

of the dorsum of the hand. Strong oblique fibrous bands

which occupies the whole width

subfascial space,

roof of a

embedded in the deep fascia, and together they form the

sum of the hand (Figs. 9.56 and 9.57). The tendons are

under the extensor retinaculum and fan out over the dor

The four tendons of the extensor digitorum emerge from

Insertion of the Long Extensor Tendons

seous spaces.

cates with the deep veins of the palm through the interos

arch, which receives digital veins and freely communi

part of the blood from the whole hand drains into the

medial side, into the basilic vein (Fig. 9.100). The greater

on the lateral side into the cephalic vein and, on the

proximal to the metacarpophalangeal joints and drains

The dorsal venous arch lies in the subcutaneous tissue

Dorsal Venous Arch (or Network)

supply from palmar digital nerves.

remainder of the dorsum of each finger receives its nerve

nerves do not extend far beyond the proximal phalanx. The

The dorsal digital branches of the radial and ulnar

the little fingers.

that supply the medial side of the ring and the sides of

-
-

Mallet Finger

flexed when the extensor tendon is taut. The last 20° of active

Avulsion of the insertion of one of the extensor tendons into

the distal phalanges can occur if the distal phalanx is forcibly

extension is lost, resulting in a condition known as mallet
finger

extension of the distal interphalangeal joint. This injury can

to its insertion into the base of the middle phalanx results in

(Fig. 9.71).

Boutonnière Deformity

Avulsion of the central slip of the extensor tendon proximal

a characteristic deformity (Fig. 9.71C). The deformity results

from flexing of the proximal interphalangeal joint and hyper-

result from direct end-on trauma to the finger, direct trauma

over the back of the proximal interphalangeal joint, or lacera-

tion of the dorsum of the finger.

C L I N I C A L N O T E S

The Radial Artery on the Dorsum

ligament of the joint (Fig. 9.65). On reaching the dorsum

longus and extensor pollicis brevis, and lies on the lateral

wrist joint, beneath the tendons of the abductor pollicis

The radial artery winds around the lateral margin of the

of the Hand

of the hand, the artery descends beneath the

n of

tendo

the extensor pollicis longus to reach the

al between

interv

the

two heads of the first dorsal interosseous

re,

muscle; he

the margins of the olecranon fossa of the humerus and

, it is attached above to

Posteriorly

head of the radius.

ulna and to the anular ligament, which surrounds the

and below to the margin of the coronoid process of the

sae and to the front of the medial and lateral epicondyles

along the upper margins of the coronoid and radial fos

, it is attached above to the humerus

Capsule: Anteriorly

Synovial hinge joint

Type:

surfaces are covered with hyaline cartilage.

ulna and the head of the radius (Fig. 9.72). The articular

capitulum of the humerus and the trochlear notch of the

This occurs between the trochlea and

Articulation:

and the shoulder joint are fully described on pages 362

The sternoclavicular joint, the acromioclavicular joint,

(Fig. 9.65).

Dorsal digital arteries pass to the thumb and index finger

take part in the anastomosis around the wrist joint.

Branches of the radial artery on the dorsum of the

(see page 403).

the artery turns forward to enter the palm of the hand

hand

Joints of the Upper Limb

and 364.

Elbow Joint

■