Human Anatomy Vol 1

muscle. It at once divides into two branches for the

adjacent sides of the thumb and the index finger.

Palm: In the palm (deep to the oblique head of the
adductor pollicis), the radial artery gives off:
1 The princeps pollicis artery which divides at the base
of the proximal phalanx into two branches for the
palmar surface of the thumb (Fig.9.32).
2 The radialis indicis artery descends between the first
dorsal interosseous muscle and the transverse head
of the adductor pollicis to supply the lateral side of
the index finger.

Deep Polmor Atch

Deep palmar arch provides a second channel connecting
the radial and uhrar arteries in the palm (the first one
being the superficial palmar arch already considered). It
is situated deep to the long flexor tendons.

Fonmsflon

The deep palmar arch is formed mainlyby the terminal
part of the radial artery, and is completed medially at
the base of the fifth metacarpal bone by the deep palmar
branch of the ulnar artery (Fi9.9.32).

trefsfr6ns

The arch lies on the proximal parts of the shafts of the
metacarpals, and on the interossei; undercover of the
oblique head of the adductor pollicis, the flexor tendons
of the fingers, and the lumbricals.
The deep branch of the ulnar nerve lies within the
concavity of the arch.

I cfies

L From its convexity, i.e. from its distal side, the arch

gives off three palmar metacarpal arteries, which run

distally in the Znd, 3rd and 4th spaces/ supply the

medial four metacarpals, and terminate at the finger

clefts by joining the common digital branches of the

superficial palmar arch (Fig. 9.32).

(^2) Dorsally, the arch gives off three (proximal)
perforating digital arteries which pass through the
medial three interosseous spaces to anastomose with
the dorsal metacarpal arteries.
The digital perforating arteries connect the palmar
digital branches of the superficial palmar arch with
the dorsal metacarpal arteries.
3 Recurrent branch arises from the concavity of the arch
and pass proximally to supply the carpal bones and
joints, and ends in the palmar carpal arch.
UTNAR NERVE
Ulnar nerve is the main nerve of the hand (like the
lateral plantar nerve in the foot).
FOREARM AND HAND
Course
Ulnar nerve lies superficial to flexor retinaculum,
covered only by the superficial slip of the retinaculum.
It terminates by dividing into a superficial and a deep
branch.
Superficial branch is cutaneous. The deep branch
passes through the muscles of the hypothenar eminence
to lie in the concavity of the deep palmar arch to end in
the adductor pollicis (Fig.9.22).
Relotions
1 The ulnar nerve enters the palm by passing
superficial to the flexor retinaculum where it lies
between the pisiform bone and the ulnar vessels.
Here the nerve divides into its superficial and deep
terminal branches (Figs 9.13a and b).
2 The superficial terminalbranch supplies the palmaris
brevis and divides into two digital branches for the
medial lVz fingers (Fig. 9.34).
3 The deep terminal branch accompanies the deep
branch of the ulnar artery. It passes backwards
between the abductor and flexor digiti minimi, and
thenbetweenthe opponens digitiminimi and the fifth
metacarpal bone, lying on the hook of the hamate.
Finally, it turns laterally within the concavity of the
deep palmar arch. It ends by supplying the adductor
pollicis muscle (Fig. 9.22).
Bronches
L Muscular branch: To palmaris brevis.
2 Cutaneous branches: Two palmar digital nerves
supply the medial one and a half fingers with their
nail beds (Fig. 9.3a).
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Fig.9.34: Distribution of the branches of the ulnar nerve a