Extensor carpi ulnaris
is a muscle
located in the human forearm
that acts to extend and adduct the wrist
Being an extensor muscle, extensor carpi ulnaris is on the posterior side of the forearm.
Origin and insertion
It originates from the lateral epicondyle
of the humerus
and the posterior border of the ulna
, and crosses the forearm to the ulnar
(medial) side to insert at the base of the 5th metacarpal
The Extensor carpi ulnaris extends
, but when acting alone inclines the hand toward the ulnar side; by its continued action it extends the elbow-joint.
The muscle is a minor extensor of the carpus in carnivores, but has become a flexor in ungulates. In this case it is described as ulnaris lateralis.