Postero lateral anconeus triangle is formed by:
Radial head, lateral epicondyle and tip of olecranon form the triangle over the posterolateral aspect of elbow joint. This space is occupied by the anconeus muscle and so known as anconeus triangle. Ref: Rockwood and Green's Fractures in Adults 6/e, Page 990-92.
Head of radius, lateral epicondyle, medial epicondyle
Head of radius, lateral epicondyle, olecranon
Olecranon, medial epicondyle, neck of radius
Neck of radius, head of radius, lateral epicondyle