Flexor digiti minimi brevis (hand)

For the muscle of the foot, see Flexor digiti quinti brevis muscle (foot)

The flexor digiti minimi brevis is a muscle in the hand that flexes the little finger. It lies in the same plane as the abductor digiti minimi, on its radial side.

Structure
It arises from the convex surface of the hamulus of the hamate bone, and the palmar surface of the flexor retinaculum of the hand, and is inserted into the ulnar side of the base of the first phalanx of the little finger.

It is separated from the abductor digiti minimi, at its origin, by the deep branches of the ulnar artery and the ulnar nerve. This muscle is sometimes not present; in these cases, the abductor digiti minimi is usually larger than normal.

It is a hypothenar muscle.

Innervation
The flexor digiti minimi brevis, like other hypothenar muscles, is innervated by the deep branch of the ulnar nerve.

Actions
The flexor digiti minimi flexes the little finger.

Etymology
The name of this muscle is Latin for the 'short flexor of the little finger'. Note that brevis is usually included to differentiate it from a longus muscle of the same name. The flexor digiti minimi longus, however, is not found in the typical human, but instead is a rare anatomical variation.