ABSTRACT
HUMERUS (FIGS. 31-34) The most proximal long bone of the forelimb, the humerus has a swollen, rounded proxi mal articulation, its head, for the shoulder joint with the scapula. Adjacent to this are two tuberosities, the greater tubercle (for attachment of the supra-and infra-spinatus muscles) and the lesser tubercle (for attach ment of the subscapularis muscle), between which lies the inter tubercular groove (for a tendon of the biceps muscle). On the lateral surface of the mid-shaft is a prominent tuberosity for the deltoid muscle, connected to the greater tubercle by a ridge. The distal end of the bone is expanded and holds a pulley-like articular surface for the elbow joint, the trochlea, to the lateral end of which is joined a further surface, the capitulum. On the caudal side of these elements is a deep pit, the olecranon fossa, with a similar pit to cranial, called the coronoid fossa. The distal end of the humerus divides either side of the these fossae into medial and lateral epicondylar areas. In some animals, clear processes extend out from these, the medial epicondyle and the lateral epicondyle. Some animals also bear a sharp crest on the caudallateral corner of the lateral epicondylar area.
