Muscle Anatomy

extensor carpi ulnaris

The extensor group of muscles occupies the posterior surface and lateral (outer) border of the forearm.


The extensor carpi ulnaris originates on the lateral condyle of the humerus.


It inserts on the fifth metacarpal bone of the hand.


Extension and adduction (ulna flexion) of the wrist. It is involved in wrist joint extension and stabilization and possibly assists in extension of the elbow.