|Extensor digiti minimi|
The synovial sheaths of the tendons on the back of the wrist. (Extensor digiti quinti proprius labeled at center left.)
|Origin||the anterior portion of the lateral epicondyle of the humerus (common extensor tendon)|
|Insertion||at the extensor expansion, located at the base of the proximal phalanx of digit V on the dorsal side|
|Artery||posterior interosseous artery|
|Nerve||posterior interosseous nerve (C7, 8)|
|Actions||extends the wrist and the little finger at all joints|
|Antagonist||Flexor digiti minimi brevis|
|Latin||musculus extensor digiti minimi|
|Anatomical terms of muscle|
It arises from the common extensor tendon by a thin tendinous slip and frequently from the intermuscular septa between it and the adjacent muscles.
Its tendon passes through a compartment of the extensor retinaculum, posterior to distal radio-ulnar joint, then divides into two as it crosses the dorsum of the hand, and finally joins the extensor digitorum tendon. All three tendons attach to the dorsal digital expansion of the fifth digit (little finger). There may be a slip of tendon to the fourth digit.
Absence of muscle rare; fusion of the belly with the extensor digitorum communis not uncommon.
Variations to the fifth extensor compartment, which the extensor digiti minimi runs through, may cause tenosynovitis and can limit the use of the extensor digiti minimi.
Extensor digiti minimi can also be bifurcated, which means split, at many different points in the muscle.
The extensor digiti minimi is a two joint muscle. It acts as an extensor in both joints. It extends the wrist, which means it moves the back of the hand toward the back of the forearm. It also extends the little finger, which means it straightens the little finger from a fist.