The anconeus muscle is a posterior/lateral extensor that plays very little role in normal arm movements.

The main radiologic importance of the muscle is to recognize its existence and differentiate it from the anconeus epitrochlearis muscle (accessory anconeus), which is variably present, but when present is located in the posterior/medial elbow. The anconeus epitrochlearis can be a cause or contributor to ulnar compression neuropathy. This patient does not have an anconeus epitrochlearis.