The anconeus is one of the muscles of the superficial layer of the posterior compartment of the forearm. It is a small triangular muscle just posterior to the elbow joint, its muscle fibres partially blend with the triceps brachii muscle.

The posterior compartment of the forearm consists of a superficial layer (7 muscles) and a deep layer (5 muscles).

The muscles in the superficial layer include:

• Brachioradialis
• Extensor carpi radialis longus
• Extensor carpi radialis brevis
• Extensor digitorum
• Extensor digiti minimi
• Extensor carpi ulnaris
• Anconeus

The muscles of the superficial layer share a common origin from the lateral epicondyle and lateral supracondylar ridge of the humerus.

All the muscles of the posterior compartment are innervated by the radial nerve.