Muscle · Hand

Opponens digiti minimi

Musculus opponens digiti minimi

The deepest hypothenar muscle, and the reason the palm can cup. It swings the fifth metacarpal forward and rotates it, deepening the hollow of the hand so the palm wraps a shape instead of pressing flat against it. Working against opponens pollicis at the other side of the hand, it closes the palmar arch — the quiet mechanism behind holding a ball, a mug, or a steering wheel securely. It is ulnar-innervated and lies hidden beneath the abductor and short flexor.