Abductor digiti minimi muscle of hand in three slips that are inserted into the ulnopalmar margin of the proximal phalanx, the palmar plate of the metacarpophalangeal joint, and the sesamoid bone when present. Some fibers insert into the finger's dorsal aponeurosis, which is why the muscle acts similar to a dorsal interosseus muscle. Additionally, the ulnar-most portion of the tendon inserts into the little finger's digital cord, and the muscle thus forms part of a structure that flexes the metacarpophalangeal joint and extends the interphalangeal joints. It is innervated by the deep branch of the ulnar nerve (C8–T1). The abductor digit minimi develops at an early
Anatomical terms of muscle need antagonistic pairs located in opposite sides of a joint or bone, including abductor-adductor pairs and flexor-extensor pairs. These consist of an extensor muscle, which "opens" the joint (by increasing the angle between the two bones) and a flexor muscle, which does the opposite by decreasing the angle between two bones. However muscles don't always work this way - sometimes agonists and antagonists contract at the same time to produce force, as per Lombard's paradox. Also, sometimes during a joint action controlled by an agonist muscle (see above definition of agonist), the antagonist will be slightly activated, naturally. This occurs