Opponens Digiti Minimi of Hand (Left) (Musculus opponens digiti minimi)
Educational content only — not medical advice.
Anatomy
The deepest hypothenar muscle, hidden under the abductor and short flexor. Uniquely among the little-finger muscles it inserts on the metacarpal rather than the phalanx, pulling the fifth metacarpal into flexion and rotation at the carpometacarpal joint — the motion that cups the palm around a held object.
Origin & insertion
From the hook of the hamate and the flexor retinaculum, to the ulnar border and palmar surface of the shaft of the fifth metacarpal.
Action
Flexes and rotates the fifth metacarpal at the carpometacarpal joint, deepening the palm.
Innervation
Deep branch of the ulnar nerve (C8–T1).
Clinical notes
It is tested indirectly — asking the patient to press the pulp of the little finger against the thumb while the fifth metacarpal is palpated for tension — because the muscle itself is not palpable. Its sparing is one of the discriminators between an ulnar lesion in the forearm and one at the wrist.
Related structures
Educational references
FAQ
What is the role of the Opponens Digiti Minimi of Hand (Left)?
The deepest hypothenar muscle, hidden under the abductor and short flexor. Uniquely among the little-finger muscles it inserts on the metacarpal rather than the phalanx, pulling the fifth metacarpal into flexion and rotation at the carpometacarpal joint — the motion that cups the palm around a held object.
Why is the Opponens Digiti Minimi of Hand (Left) clinically important?
It is tested indirectly — asking the patient to press the pulp of the little finger against the thumb while the fifth metacarpal is palpated for tension — because the muscle itself is not palpable. Its sparing is one of the discriminators between an ulnar lesion in the forearm and one at the wrist.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details