Anatomy, Shoulder and Upper Limb, Hand Volar Arch Arteries

Structure and Function

The arteries of the volar surface of the hand comprise the superficial and deep volar arches. These arches and their branches establish an extensive collateral network that delivers oxygenated blood to all regions of the hand and digits.[3]

The superficial volar arch serves as the dominant vascular structure of the palm. This arch arises primarily from the ulnar artery with additional contribution from the superficial branch of the radial artery (see Image. Forearm Artery Dissection). The ulnar artery enters the hand superficial to the flexor retinaculum through the ulnar (Guyon) canal and terminates in the superficial volar arch, where an anastomosis forms with the superficial radial branch (see Image. Guyon Canal Zones). The superficial radial branch courses superficial to the flexor retinaculum to complete the arch. The superficial volar arch lies superficial to the flexor tendons and deep to the palmar aponeurosis, extending from the 1st webspace to the hook of the hamate and reaching a more distal level than the deep volar arch.

Branches of the superficial volar arch include 3 common palmar digital arteries that traverse the palm between the finger webs. Each common palmar digital artery divides at the webspace into 2 proper palmar digital arteries that supply the opposing sides of digits 2, 3, 4, as well as the lateral aspect of the 5th digit. The medial surface of the 5th digit receives arterial supply from an additional branch of the superficial volar arch.[4]

The deep volar arch forms from the dorsal radial artery and the deep palmar branch of the ulnar artery. Before reaching the flexor retinaculum, the radial artery gives off the superficial branch of the radial artery and then continues as the dorsal radial artery. The dorsal radial artery continues its course by curving around to enter the dorsal aspect of the hand while passing the scaphoid and trapezium through the floor of the anatomical snuffbox.[5] From there, the blood vessel passes between the 2 heads of the 1st dorsal interosseous muscle to reenter the palmar aspect of the hand.[6] On the palmar side, the radial artery turns medially and terminates in the deep volar arch, where it anastomoses with the deep palmar branch of the ulnar artery.

The deep palmar branch of the ulnar artery completes the deep volar arch. The deep volar arch is localized deep to the flexor tendons of the hand. This arterial arch lies between the flexor tendons and the metacarpal bones and is proximal to the superficial volar arch.

Arising from the deep volar arch are 3 palmar metacarpal arteries that anastomose with the common palmar digital arteries from the superficial volar arch. The deep volar arch also provides arterial supply to the thumb and the lateral side of the index finger. The radial artery gives off 2 branches—the princeps pollicis and radialis indicis arteries—as it turns onto the palmar aspect of the hand. The princeps pollicis artery runs along the palmar aspect of the 1st metacarpal and bifurcates distally into 2 palmar digital arteries that supply each side of the thumb. The radialis indicis artery courses along the 1st dorsal interosseous muscle to supply the lateral side of the index finger.[7]

Embryology

The current theory of embryonic development of the hand arterial pattern proposes a combined process of vasculogenesis and remodeling. At stage 12, an initial capillary network arises from the dorsal aorta and expands into the developing limb bud. Simultaneously, the proximal segments of this network begin to enlarge, and arterial walls start differentiating by stage 13.

From stages 13 to 21, differentiation proceeds in a proximal-to-distal sequence, beginning with the ulnar, interosseous, and median arteries.[8] The radial artery develops at stage 18 and reaches its final differentiated morphology by stage 21. By this stage, the definitive arterial pattern of the hand, including the palmar arches, is established.

The precise mechanisms guiding arterial development are incompletely understood. One hypothesis emphasizes the roles of oxygenation, nutrient supply, and hemodynamic forces. An alternative hypothesis proposes a genetic component in determining the arterial pattern.[9]

Blood Supply and Lymphatics

The superficial and deep volar arterial arches are each accompanied by paired venae comitantes, forming the superficial and deep palmar venous arches. These veins drain deoxygenated blood from the hand and fingers along pathways corresponding to the branches of the arterial arches. The common palmar digital veins receive blood from the proper palmar digital veins and empty into the superficial palmar venous arch, which ultimately drains into the radial vein. The palmar metacarpal veins, collecting blood from the metacarpal region, drain into the deep palmar venous arch. Certain branches of the palmar metacarpal veins communicate with the dorsal metacarpal veins and terminate in the radial veins, as well as the superficial veins on the dorsum of the wrist.

Lymphatic drainage of the hand similarly divides into superficial and deep systems. Superficial lymphatic vessels course adjacent to major superficial veins, whereas deep lymphatic vessels follow the trajectories of the principal deep veins.[10]

Nerves

Sympathetic fibers provide innervation to the arteries of the hand, with the 2nd and 3rd thoracic ganglia serving as the primary sources of sympathetic input.[11] Arterioles constrict to reduce blood flow to the superficial tissues and distal phalanges in response to cold exposure, thereby minimizing heat loss.

Muscles

The hand contains an extensive network of collateral vessels, ensuring delivery of oxygenated blood to all muscular structures of the hand and digits.[12] Injury to a single vessel does not necessarily compromise perfusion, as anastomotic connections maintain blood flow. This collateral network preserves oxygen delivery to regions at risk of ischemia following vascular injury.

Physiologic Variants

The arteries of the hand form a highly branched and anastomosed network, resulting in numerous anatomic variations of arterial patterns. These variants are classified as either complete or incomplete, affecting the superficial or deep arches.[13] An arch is considered complete when an anastomosis exists between its contributing vessels, and incomplete when such a connection is absent. Advances in hand microsurgery have increased the clinical significance of understanding these vascular variations. A recent meta-analysis reported a complete superficial volar arch in 81.3% of cases. Seven distinct types of complete superficial volar arches and 5 types of incomplete superficial volar arches have been documented. The deep volar arch exhibits less variability, with a complete arch observed in 95.2% of cases.[14]

Surgical Considerations

The radial artery is frequently utilized for blood gas sampling, arterial line placement, catheterization, and grafting in coronary revascularization. Anastomoses between the ulnar and radial arteries, forming the deep and superficial volar arches, generally preserve hand perfusion if an artery becomes occluded during such procedures. Complications, including distal ischemia and limb compromise, can occur when collateral circulation is insufficient to maintain adequate flow.[15] Therefore, assessment of collateral blood flow is essential to ensure sufficient perfusion following intervention. The Allen test and modified Allen test provide reliable methods for evaluating collateral circulation prior to procedures.[16][17]

Clinical Significance

The arterial supply of the hand and fingers is critical for maintaining tissue viability. Collateral circulation typically preserves perfusion if the ulnar or radial artery is occluded or damaged. However, patients with anatomic vascular variations may develop digital ischemia and limb compromise when collateral flow is insufficient. Awareness and documentation of significant vascular variants are essential to prevent adverse outcomes.

Raynaud syndrome is an idiopathic disorder characterized by intermittent digital ischemia, frequently accompanied by paresthesia and pain. Episodes are usually triggered by cold exposure or emotional stress.[18] Cervicodorsal presynaptic sympathectomy provides an effective surgical treatment, involving excision of a segment of the sympathetic chain to dilate digital arteries.

Other Issues

Traumatic hand injuries frequently involve the common digital arteries. Surgical repair of transected common digital arteries may be achieved by mobilizing the superficial palmar arch distally to reestablish arterial continuity and restore perfusion.[19]