Corpus: Opponens digiti minimi muscle
from latin: digitus - finger; opponere - to oppose
Synonym: opponens digiti quinti
Definition
The opponens digiti minimi muscle is a short, triangular muscle that belongs to the hypothenar muscles of the hand and lies under the abductor digiti minimi muscle and the flexor digiti minimi brevis muscle.
Anatomy
Origin
The muscle originates from the hamulus of the hamate bone and the ligament structures of the flexor retinaculum.
Insertion
The muscle inserts broadly on the ulnar side of the fifth metacarpal bone (Os metacarpale V).
Innervation
The innervation of the opponens digiti minimi muscle is provided by the deep branch of the ulnar nerve from the brachial plexus (segments: C8 and Th1).
Function
The opponens digiti minimi muscle is responsible for the opposition (flexion) of the little finger.
Clinic
If the muscle is non-functional, the Schaeffer’s test (opposition and adduction of thumb and little finger) may yield a negative result.