Upper limb

Abductor Digiti Minimi (hand)

Musculus abductor digiti minimi manus

Origin

Pisiform bone and the tendon of flexor carpi ulnaris

Insertion

Ulnar side of the base of the proximal phalanx of the little finger, with extension into the extensor hood

Function

Abduction of the little finger; assists opposition of the little finger to the thumb

Innervation

Ulnar nerve, deep (motor) branch

Movement & chain

Part of the hypothenar muscles; works together with opponens digiti minimi and flexor digiti minimi brevis in cupping the hand (e.g. holding a ball).

Palpation

Easily felt as the most ulnar muscle belly of the hypothenar eminence, just distal to the pisiform bone, during active abduction of the little finger.

Clinical

In compression of the ulnar nerve in Guyon's canal (for example from prolonged pressure on the hypothenar, as in cycling), weakness and atrophy of this muscle are often the first to appear.

Segmental innervation

Ulnar nerve, C8-T1.

In clinical practice

Routinely used in clinical neurophysiology as the recording muscle in nerve conduction studies of the ulnar nerve.

Region in the model

Upper limb