Anconeus muscle

The anconeus muscle (or anconaeus/anconæus) is a small muscle on the posterior aspect of the elbow joint.

Some consider anconeus to be a continuation of the triceps brachii muscle. Some sources consider it to be part of the posterior compartment of the arm, while others consider it part of the posterior compartment of the forearm.

The anconeus muscle can easily be palpated just lateral to the olecranon process of the ulna.

Structure

Anconeus originates on the posterior surface of the lateral epicondyle of the humerus and inserts distally on the posterior surface of the ulna.

Innervation

Anconeus is innervated by a branch of the radial nerve (cervical roots 7 and 8) from the posterior cord of the brachial plexus called the nerve to the anconeus. The somatomotor portion of radial nerve innervating anconeus bifurcates from the main branch in the radial groove of the humerus. This innervation pattern follows the rules of innervation of the musculature of the posterior forearm (extensor) compartment by the radial nerve.