VASCULAR SUPPLY OF THE HAND AND
FINGER
The ulnar
artery, with its accompanying nerve, enters the hand superficial to the
flexor retinaculum and to the radial side of the pisiform (see Plates 4-10 and
4-11). It descends, curving radially, to about the midpalm and there
anastomoses with the superficial palmar branch of the radial artery. This
branch passes across or through the muscles of the thenar eminence, supplies
this group of muscles, and emerges medial to the eminence to help form the
superficial palmar arterial arch. The arch is convex distalward and crosses the
palm at the level of the line of the completely abducted thumb.
The branches of the superficial arch supply the medial
three and one-half digits; the radial one and one-half digits are supplied from
the deep palmar arterial arch. The superficial arch gives origin to three common
palmar digital arteries, which proceed distalward on the flexor tendons and
lumbrical muscles and superficial to the digital nerves of the palm. They unite
at the webs of the fingers with the palmar metacarpal arteries and with distal
perforating branches of the dorsal metacarpal arteries. From the short trunks
thus formed spring proper palmar digital arteries.
Two proper palmar digital arteries run distalward
along the adjacent margins of the second to fifth digits. A proper digital
branch to the ulnar side of the fifth digit arises from the ulnar artery in the
hypothenar compartment. At the webs of the fingers, the digital nerves cross
the arteries to become superficial to them along the margins of the digits.
Thus, in each digit, the palmar and dorsal digital arteries lie within the span
of the corresponding cutaneous nerves. The proper palmar digital arteries
anastomose to form terminal plexuses in the fingers. They also give off
branches that supply the last two dorsal segments of the digits.
At the wrist, the radial artery shifts from the
expanded palmar surface of the radius, through the floor of the anatomic
snuffbox, to reach the dorsum of the hand at the proximal end of the first
dorsal interosseous space. As it passes under the tendon of the abductor
pollicis longus muscle, it gives origin to its dorsal carpal branch; continuing
distally over the first dorsal interosseous space, it gives origin to the first
dorsal metacarpal artery. (The radial artery then turns deeply into the
palm of the hand and participates in forming the deep palmar arterial arch.)
The dorsal carpal branch of the radial artery passes ulnarward across the
distal row of carpal bones and under the extensor tendons and joins the dorsal
carpal branch of the ulnar artery. Thus is formed the dorsal carpal arterial
arch.
Three dorsal metacarpal arteries descend from
this arch on the dorsal
interosseous muscles of the second, third, and fourth intermetacarpal
intervals, respectively. Opposite the heads of the metacarpals, these vessels
divide into proper dorsal digital arteries, which proceed distally along
the dorsal borders of contiguous digits. These vessels are small and fail to
reach the distal phalanges of the digits. Anastomoses are formed between the
dorsal metacarpal arteries and the palmar arterial system in two locations: by perforating branches at
the bases of the metacarpals and at the division into proper dorsal digital
arteries.
The deep palmar arterial arch is formed by the
junction of the terminal portion of the radial artery and the deep branch of
the ulnar artery. The radial artery enters the palm at the base of the first
intermetacarpal space by penetrating between the two heads of origin of the
first dorsal interosseous muscle. Passing then between the transverse and
oblique heads of the adductor pollicis muscle, it joins the deep branch of the
ulnar artery.
The princeps pollicis artery arises from the
radial artery as it emerges from the first dorsal interosseous muscle. At the
head of the first metacarpal, it provides two proper palmar digital branches for the thumb. The radialis indicis
artery arises with the princeps pollicis to run along the radial side of
the index finger. It is a proper digital artery to the radial side of the index
finger.
From the convexity of the arch arise three palmar
metacarpal arteries. These descend under the palmar interosseous fascia of
the second to fourth intermetacarpal intervals. At the webs of the fingers,
they join the common digital arteries from the superficial arch. Recurrent
carpal branches are small. They ascend to and help form the palmar carpal
network. Perforating branches anastomose with the dorsal metacarpal
arteries on the dorsum
of the hand.
