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:

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.

Origin
  • Lateral epicondyle of the humerus
Insertion
  • Lateral surface of olecranon and proximal posterior surface of the ulna
Innervation
  • Radial nerve
Blood Supply
  • Interosseus recurrent artery (from the posterior interosseus artery)
Action
  • Assists in extension
  • Stabilises the elbow during pronation and supination
  • Pulls the slack out of the elbow joint capsule which prevents it being pinched during extension