Abductor Digiti Minimi Muscle, Lateral View

Description

Along the ulnar (medial) border of the hand, the abductor digiti minimi forms the most superficial contour of the hypothenar eminence, running longitudinally from the pisiform region and flexor retinaculum toward the proximal phalanx of the fifth digit. From a lateral perspective, its fleshy belly sits superficial to the opponens digiti minimi and adjacent to the flexor digiti minimi brevis, while the fifth metacarpal lies deep and slightly radial to the muscle mass. Distally, the tendon blends with the medial side of the little finger and the extensor expansion, aligning the muscle with abduction at the metacarpophalangeal joint. Clear surface anatomy. This angle matters because the abductor digiti minimi is both a functional driver of little-finger splay and a practical landmark for ulnar-sided hand pathology and operative exposure. Denervation from ulnar neuropathy, classically at Guyon canal, can flatten the hypothenar contour and weaken abduction of the fifth digit, a finding that pairs well with testing of the first dorsal interosseous and Froment sign. Surgical approaches to the hypothenar region, including release of ulnar tunnel compression or exploration after hook of hamate fracture, benefit from a solid mental model of what is superficial, what is deep, and where the ulnar neurovascular bundle runs relative to the muscle mass. Hand anatomy courses and cadaver lab manuals can use this view to orient learners to hypothenar compartment layering and to differentiate intrinsic muscles during dissection. It also reads well in clinical teaching files for EMG localization, ulnar nerve entrapment discussions, and hand surgery patient education where visible wasting of the hypothenar eminence is a key counseling point. Anatomical accuracy verified by SciePro's Medical Advisory Board.