Interossei Muscles, Posterior View

Description

Presented from a posterior (dorsal) perspective of the left hand, the metacarpals and phalanges form the bony framework while the interossei occupy the intermetacarpal spaces as paired bellies along the shafts. Dorsal interossei sit more centrally between adjacent metacarpals and angle distally toward the bases of the proximal phalanges and extensor expansions, while the palmar interossei lie more on the palmar aspect and are only partially appreciated from this viewpoint. Carpal bones at the proximal hand establish the base for the metacarpal rays, and the metacarpophalangeal and interphalangeal joints align distally in a clear proximal to distal sequence. Orientation is unambiguous. Finger control lives in the details. This dorsal angle is the cleanest way to teach dorsal interossei as abductors of digits 2 to 4 away from the axial line through the third digit, and to connect their tendinous insertions to the extensor hood where they also contribute to metacarpophalangeal flexion with interphalangeal extension. Clinically, it supports examination logic for ulnar nerve lesions, weakness of interossei produces impaired finger abduction and adduction with a characteristic pattern of clawing at the ulnar digits, and it also helps explain why dorsal interosseous atrophy becomes visible early in chronic ulnar neuropathy. These relationships matter in tendon balance. Use it in upper limb anatomy and hand surgery teaching to anchor the relationship between interossei, metacarpals, and the extensor mechanism, or in a rehab handout explaining intrinsic muscle strengthening after ulnar nerve decompression or repair. It also fits textbook spreads on intrinsic hand muscles and clinical skills guides that cover Froment sign and interosseous strength testing. Anatomical accuracy verified by SciePro's Medical Advisory Board.