Interossei Muscles, Posterior View

Description

Presented from a posterior (dorsal) perspective, the right hand is shown with the dorsal interossei occupying the intermetacarpal spaces between metacarpals I through V, their muscle bellies lying deep to the extensor tendons as they course distally toward the digits. Extensor digitorum tendons run longitudinally over the dorsum, expanding into the dorsal digital (extensor) expansions at the proximal phalanges, while slips of extensor indicis and extensor digiti minimi are typically visible on the ulnar side of the index and little fingers. Proximally, the extensor compartments of the distal forearm lead into the extensor retinaculum at the wrist, with carpal bones and metacarpophalangeal joint lines providing bony reference points. Small but decisive. Dorsal interossei drive finger abduction at the metacarpophalangeal joints (DAB) and, through the extensor hood, contribute to coordinated PIP and DIP extension, so a dorsal view clarifies how intrinsic hand muscles interact with the extrinsic extensors rather than acting in isolation. That relationship matters in ulnar nerve palsy, where denervation of interossei produces loss of finger abduction and a characteristic imbalance at the MCP joints, and in intrinsic tightness after trauma where tension transmitted through the extensor expansion limits flexion. Hand surgeons also think in this plane when addressing dorsal approaches to the metacarpals and when evaluating extensor tendon subluxation or sagittal band injury at the MCP level. Ideal for gross anatomy and hand anatomy teaching blocks, operative atlases illustrating the extensor mechanism, and rehabilitation materials explaining intrinsic muscle function after ulnar neuropathy, metacarpal fracture, or tendon repair. Anatomical accuracy verified by SciePro's Medical Advisory Board.