Extensor Digitorum Tendons, Posterior View

Description

Running distally from the posterior forearm into the dorsum of the hand, the extensor digitorum tendons are shown as four discrete slips emerging from the common extensor compartment and passing deep to the extensor retinaculum at the level of the carpus. Each tendon courses centrally over the dorsal aspect of the second through fifth metacarpals, then fans into the extensor expansions over the proximal phalanges, with the index and little finger tendons sitting slightly radial and ulnar, respectively. Red-highlighted vessels track along the dorsoradial and dorsoulnar wrist, consistent with branches of the radial and ulnar arteries contributing to the dorsal carpal arch and dorsal metacarpal arteries adjacent to the tendon paths. Separation becomes obvious near the metacarpophalangeal joints. Dorsal tendon anatomy matters when you are trying to explain the difference between pure tendon rupture and failure of the extensor hood, because loss of metacarpophalangeal extension from sagittal band rupture (boxer’s knuckle) looks and behaves differently than attritional rupture of extensor digitorum in rheumatoid arthritis at the level of the distal ulna. Surgeons also orient themselves to these tendons for dorsal approaches to the metacarpals and phalanges, where the extensor retinaculum and dorsal carpal arterial network create a narrow interval that can complicate dissection and skin-flap planning. Landmarks are unforgiving. Use this artwork for teaching dorsal hand and wrist anatomy in gross anatomy, hand therapy curricula, or orthopaedic and plastic surgery modules on extensor tendon zones, tendon repair, and postoperative splinting positions. It also reads well in manuscripts on dorsal wrist approaches and in patient-facing materials explaining extensor tendon lacerations and repair. Anatomical accuracy verified by SciePro's Medical Advisory Board.