Deep Palmar Arch, Posterior View

Description

Arcing transversely across the proximal palm, the deep palmar arch is shown closely applied to the bases of the second through fifth metacarpals, immediately distal to the carpal bones and deep to where the long flexor tendons would normally pass. Radially, the arch continues from the radial artery after it courses dorsally through the anatomical snuffbox and between the heads of the first dorsal interosseous, then turns medially to anastomose with the deep branch of the ulnar artery. From the convexity of the arch, palmar metacarpal arteries run distally in the intermetacarpal spaces toward the digits, while the metacarpals and phalanges provide fixed landmarks for its position. Bone anchors the story. A posterior (dorsal) perspective helps clarify how the radial artery reaches the deep palmar system, a point that can be confusing when learners only see palmar dissections. This relationship matters in hand trauma and reconstructive planning because lacerations across the first web space, dorsal metacarpal fractures, or surgical exposure around the carpometacarpal joints can jeopardize the arterial continuity that feeds the common and proper palmar digital arteries. It also frames the arterial contribution differences between the superficial palmar arch (ulnar-dominant) and the deep palmar arch (radial-dominant), which underlie patterns of ischemia when either artery is occluded. Hand anatomy faculty can drop this figure directly into upper-limb blocks to teach palmar vascular anatomy alongside osteology of the carpus and metacarpals, and it also suits surgical textbooks discussing radial artery harvest, Allen test interpretation, and dorsal approaches to carpometacarpal fixation. Clinicians may find it useful for patient-facing explanations of why a dorsal injury can still threaten palmar perfusion. Anatomical accuracy verified by SciePro's Medical Advisory Board.