Superficial palmar arch

At a glance

English

Superficial palmar arch

Latin (TA2)

Arcus palmaris superficialis

System

Artery

Region

Upper limb

Side

Paired, left and right

About the superficial palmar arch

The superficial palmar arch is a curved artery lying in the palm beneath the palmar aponeurosis and in front of the long flexor tendons and the branches of the median nerve. It is formed chiefly by the end of the ulnar artery, which enters the hand beside the pisiform bone and sweeps laterally. The loop is usually closed by a slender superficial palmar twig of the radial artery. In some hands that branch does not reach it, and the arch instead links with the princeps pollicis, the radialis indicis or a persisting median artery; in others it simply ends without joining any of them.

The arch bows towards the fingers, its convex side facing distally. A practical surface guide is Kaplan's cardinal line, drawn across the palm from the web between thumb and index finger to the hamate's hook: the arch lies about a centimetre beyond it. It therefore lies further from the wrist than the deep palmar arch, which sits about a finger's breadth closer to the wrist on the bases of the metacarpals.

From its convex border come the vessels to the fingers. A proper palmar digital artery runs to the medial side of the little finger, and three common palmar digital arteries pass distally over the second, third and fourth lumbricals. Each common artery is joined by a palmar metacarpal artery from the deep arch and then splits near the metacarpophalangeal joints into two proper digital arteries for the facing sides of adjacent fingers. In this way the arch supplies the medial three and a half fingers, while the thumb and the radial side of the index finger rely mostly on the radial artery.

The links between the two arches and between the radial and ulnar arteries mean either forearm artery can usually keep the hand alive alone. The Allen test checks this before a radial artery is punctured or harvested. Because the arch lies only just beneath the aponeurosis, a deep cut in the palm can open it and bleed heavily, and surgeons releasing the carpal tunnel or a contracted aponeurosis take care to stay proximal to it.

Course and supply

Arises from

The continuation of the ulnar artery beyond the pisiform bone, usually completed on the thumb side by a superficial palmar twig of the radial artery.

Ends in

Gives the three common palmar digital arteries and the proper palmar digital artery to the medial side of the little finger; ends by joining the radial contribution or tapering out in the thenar region.

Supplies

Supplies the palm and the medial three and a half fingers, and links with the deep palmar arch through the digital and metacarpal arteries.