Extensor digiti minimi muscle

The extensor minimi digiti (extensor digiti quinti proprius) is a slender muscle of the forearm, placed on the medial side of the Extensor digitorum communis, with which it is generally connected.

It arises from the common Extensor tendon by a thin tendinous slip, from the intermuscular septa between it and the adjacent muscles.

Its tendon runs through a compartment of the dorsal carpal ligament behind the distal radio-ulnar joint, then divides into two as it crosses the hand, and finally joins the expansion of the Extensor digitorum communis tendon on the dorsum of the first phalanx of the little finger.

Variations
An additional fibrous slip from the lateral epicondyle; the tendon of insertion may not divide or may send a slip to the ring finger.

Absence of muscle rare; fusion of the belly with the Extensor digitorum communis not uncommon.