Opponens digiti minimi !
The opponens digiti minimi is the deepest muscle of the little-finger mound; it brings the little finger forward to cup the palm.
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What it is
A deep hypothenar muscle along the 5th metacarpal.
What it does
Cups the palm by bringing the little finger forward.
Key facts
- Origin
- Hook of the hamate, flexor retinaculum
- Insertion
- Medial border of the 5th metacarpal
- Action
- Brings the 5th metacarpal forward and rotates it (cups the palm)
- Nerve
- Deep branch of the ulnar nerve (C8–T1)
- Blood supply
- Deep palmar branch of the ulnar artery
Relations
- Superficial
- Abductor digiti minimi and flexor digiti minimi
- Deep
- The shaft of the 5th metacarpal
- Contents
- The deep branch of the ulnar nerve with the deep branch of the ulnar artery, which pierce it on their way to the deep palmar arch
How to find it
Deep; its action shows when the little finger is brought across to meet the thumb, deepening the hollow of the palm and firming the hypothenar eminence along the 5th metacarpal.
Examination
- Little finger to thumb opposition: a palm that stays flat, with hypothenar wasting, supports a lesion of the deep branch of the ulnar nerve
On imaging
Lies deep in the hypothenar eminence, arising from the hook of the hamate; a landmark more than a target. Hook of hamate fractures, typical of golf, bat or racquet grips, are easily missed on routine films: a carpal tunnel view or CT shows them. MRI shows hypothenar denervation oedema with an ulnar nerve lesion in or above Guyon's canal.
Clinical notes
- In ulnar nerve palsy the hypothenar eminence flattens and the palm loses its cupping, weakening grip on cylindrical objects
- Because the deep branch runs through it, deep hypothenar injuries can damage the nerve supply to most intrinsic muscles
Anatomical variants
- May be fused with flexor digiti minimi
Test yourself
Think of the answer, then tap the question to see it.
Which hypothenar muscle inserts on the metacarpal?
The opponens digiti minimi, on the medial border of the 5th metacarpal, a mirror image of opponens pollicis.
What passes through the opponens digiti minimi?
The deep branch of the ulnar nerve and the deep branch of the ulnar artery, on their way to the deep palm.
What happens to the palm in ulnar nerve palsy because of opponens digiti minimi loss?
The hypothenar eminence flattens and the palm loses its cupping, weakening grip on cylindrical objects.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- musculus opponens digiti minimi manus TA2 2531
- Official Spanish (DeCS)
- Músculo oponente del dedo meñique de la mano
- English (TA2)
- Opponens digiti minimi
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Shoulder and Upper Limb, Hand Hypothenar Eminence.
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Representative model, for educational purposes only.
