In name the muscles that form the hypothenar eminence on the ulnar side of the palm are similar to the three thenar muscles. Abductor digiti minimi is the most ulnar of the group; it arises from the pisiform bone and flexor retinaculum and is inserted into the ulnar side of the base of the proximal phalanx and into the extensor expansion. A sesamoid bone is common in its tendon. Flexor digiti minimi arises from the flexor retinaculum and is inserted into the base of the proximal phalanx. Opponens digiti minimi also arises from the flexor retinaculum and the hook of the hamate and is inserted into the ulnar border of the fifth metacarpal bone.
Nerve supplies of hypothenar muscles:
By the deep branch of the ulnar nerve (C8, T1).
Actions of hypothenar muscles:
All three hypothenar muscles help to cup the palm and assist in the grip on a large object.