Capitulum of the humerus Capitulum of the humerus In human anatomy of the arm, the capitulum of the humerus is a smooth, rounded eminence on the lateral portion of the distal articular surface of the humerus. It articulates with the cupshaped depression on the head of the radius, and is limited to the front and lower part of the bone. In non-human tetrapods, the name capitellum is generally used, with "capitulum" limited to the anteroventral articular facet of the rib (in archosauromorphs). Lepidosaurs show a distinct capitellum and trochlea on the centre of the ventral (anterior in upright taxa) surface of the humerus at
Lower extremity of humerus the olecranon is received in extension of the forearm. These fossæ are separated from one another by a thin, transparent lamina of bone, which is sometimes perforated by a supratrochlear foramen; they are lined in the fresh state by the synovial membrane of the elbow-joint, and their margins afford attachment to the anterior and posterior ligaments of this articulation. The epicondyles are continuous above with the supracondylar ridges. Lower extremity of humerus The lower extremity of the humerus is flattened from before backward, and curved slightly forward; it ends below in a broad, articular surface, which is divided into two