The opponens digiti minimi is one of the intrinsic muscles of the hand within the hypothenar group. The opponens digiti minimi is a triangular muscles which lies deep to the other 2 hypothenar muscles, the abductor digiti minimi and the flexor digiti minimi brevis.
The hypothenar muscles are innervated by the deep branch of the ulnar nerve, the thenar group are innervated by the recurrent branch of the median nerve.
The intrinsic muscles of the hand are involved with precision movements and consist of the following muscles:
- Thenar muscles: flexor pollicis brevis, abductor pollics brevis, opponens pollicis
- Hypothenar muscles: abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi
- Lumbricals
- Interosseus muscles
- Other: palmaris brevis, adductor pollicis
The intrinsic muscles of the hand are innervated by the deep branch of the ulnar nerve, except the thenar muscles and the lateral two lumbricals. A mnemonic for remembering this is Meat LOAF, Meat = Median nerve innervates the Lateral lumbricals, Opponens pollicis, Abductor pollicis brevis and Flexor pollicis brevis
Origin
- Hook of hamate and adjacent flexor retinaculum
Insertion
- Length of the medial margin of little finger metacarpal
The base of the muscle is penetrated by the ulnar artery and nerve.
Action
- Flexes and laterally rotates the little finger metacarpal at the carpometacarpal joint (analagous action to opposition of the thumb).
Innervation
- Deep Branch of Ulnar Nerve
Blood Supply
- Deep palmar arch (from ulnar artery)