Superficial palmar arch
The superficial palmar arch is an anastomotic vessel found in the palmar (volar) compartment of the hand. Its main source is the ulnar artery, with a smaller contribution from the radial artery. In some cases, the radialis indicis, or the princeps pollicis arteries participate in this anastomosis instead of the radial artery.
The main function of the superficial palmar arch is to provide blood supply to the phalanges, metacarpophalangeal and interphalangeal joints of digits 2-4. It does so via its three branches called the common palmar digital arteries.
|Origin||Ulnar artery, superficial palmar branch of radial artery|
|Branches||Common palmar digital arteries|
|Supply||Proximal, middle and distal phalanges of digits 2-4, metacarpophalangeal and interphalangeal joints of digits 2-4, soft tissue of digits 2-4|
This article will discuss the anatomy and function of the superficial palmar arch.
The superficial palmar arch arises from the ulnar artery at the level of the horizontal line that passes through the distal margin of the base of the thumb. It then courses anterolaterally, reaching the midshaft of the carpal bones. From here, it takes a posterolateral course towards the radial side of the hand, forming a distally convex arch across the palm. Once it reaches the lateral side of the palm, it anastomoses with the superficial palmar branch of the radial artery. The anastomosis is located at the same level as the origin of the superficial palmar arch from the ulnar artery.
The superficial palmar arch is located superficially in the palm, being deep to the palmaris brevis muscle and the palmar aponeurosis. It is superficial to and courses across the palmar surfaces of the flexor digiti minimi muscle, the tendons of the long flexors and the lumbrical muscles and the palmar branches of the median nerve.
Branches and supply
The superficial palmar arch gives off three branches that arise from its distal convexity; the common palmar digital arteries. These branches further divide into the proper palmar digital arteries, which reach the tips of the digits and terminate by comprising the arterial arcades.
The common palmar digital arteries course distally across the second to fourth lumbricals, where each of them anastomoses with a corresponding palmar metacarpal branch from the deep palmar arch. These arteries supply the proximal phalanges, metacarpophalangeal and proximal interphalangeal joints of the digits 2-4. Shortly after the anastomosis with the corresponding palmar metacarpal branch, each common palmar digital artery divides into two proper palmar digital arteries:
The proper palmar digital arteries from each pair course along the adjacent sides of the digits 2-4. They are located deep to the dorsal digital nerves, with whom they traverse the space bounded by the Grayson’s and Cleland’s ligaments. In this part of their route, each proper palmar digital artery gives off the two dorsal branches that anastomose with the dorsal digital arteries and supply the corresponding distal interphalangeal joint, middle and distal phalanges and their surrounding soft tissue.
Once they reach the tips of the digits, the proper palmar digital arteries give off terminal branches that course towards the opposite side of the corresponding digit and anastomose with the same branches of their contralateral counterparts. These anastomoses comprise proximal, superficial and subungual arterial arcades that supply the distal elements of the digits 2-4.
Learn more about the vessels of the hand with our articles, video tutorials, quizzes, and labeled diagrams.
In around 30% of the population, the superficial palmar arch is formed only by the ulnar artery. In another 30%, it is completed by either the radial indicis artery or the princeps pollicis artery.
Kaplan’s cardinal line
Kaplan’s cardinal line (KCL) is a surgical landmark for the superficial palmar arch, used to identify the location of the superficial palmar arch on the surface of the palm and avoid its injuries from surgical incisions. It is presented by a line that extends from the apex of the interdigital fold between the thumb and the index finger to the hook of hamate.