Opponens digiti minimi muscle of hand
Musculus opponens digiti minimi manus
Opponens digiti minimi is the deepest hypothenar muscle, rolling the little finger metacarpal forward to cup the palm.
At a glance
- English
- Opponens digiti minimi muscle of hand
- Latin (TA2)
- Musculus opponens digiti minimi manus
- System
- Muscle
- Region
- Upper limb
- Side
- Paired, left and right
About the opponens digiti minimi muscle of hand
Opponens digiti minimi is a small triangular muscle on the ulnar side of the palm. Of the three hypothenar muscles it lies deepest, covered by the abductor and short flexor of the little finger and, near the skin, by the thin palmaris brevis.
It takes origin from the hook of the hamate and the neighbouring part of the flexor retinaculum, the band that roofs the carpal tunnel. Its fibres fan downward and medially and attach along the full length of the ulnar border of the fifth metacarpal, on its front. Unlike the other two hypothenar muscles, it ends on the metacarpal and does not reach the finger bones. The deep branches of the ulnar nerve and artery pass close to its origin, between it and the short flexor.
The muscle pulls the fifth metacarpal forward and rotates it slightly towards the thumb at the carpometacarpal joint. This deepens the hollow of the palm and brings the little finger round to meet the thumb, as in opposition or in cupping water. It also helps grip a round handle. Its nerve is the deep ulnar branch. Its blood supply is from the ulnar artery through its deep palmar branch.
Weakness of this muscle, with the other hypothenar muscles, is a sign of ulnar nerve damage at the wrist, at Guyon canal, or higher up. The hypothenar pad becomes flat, and the little finger can no longer swing round to touch the thumb tip. Because it arises from the hook of the hamate, a fracture there can also make the muscle painful to use.
Attachments, action and supply
- Origin
- Hook of the hamate and the adjacent flexor retinaculum.
- Insertion
- Whole length of the ulnar border of the fifth metacarpal, on its palmar side.
- Action
- Draws the fifth metacarpal forward and rotates it laterally, cupping the palm and bringing the little finger towards the thumb.
- Nerve supply
- Ulnar nerve, deep branch (C8, T1).
- Blood supply
- Deep palmar branch of the ulnar artery.
Anthromica
See the opponens digiti minimi muscle of hand where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
