Abductor digiti minimi of hand

The abductor digiti minimi of hand is a prominent muscle of the hypothenar eminence, located along the ulnar border of the hand.

Origin

It originates from the pisiform bone, the pisohamate ligament, and the tendon of the flexor carpi ulnaris.

Insertion

The muscle travels distally along the ulnar side of the hand and has a somewhat variable insertion. Most commonly, it inserts via two tendinous slips:

• One slip attaches to the ulnar side of the base of the proximal phalanx of the fifth digit (a bone insertion).

• The other slip connects to the extensor expansion of the little finger (an extensor insertion).

However, in some individuals, only the bone insertion is present.

Innervation

The abductor digiti minimi of hand is innervated by the deep branch of the ulnar nerve.

Actions

Functionally, the abductor digiti minimi's primary role is to abduct the little finger at the metacarpophalangeal (MCP) joint, moving it away from the ring finger. It also contributes by assisting in flexion at this same joint.