Thoracic Limb
Arm (Brachium)
Humerus: The head of the Humerus is the part that articulates with the scapula. The greater tubercle is convex at its summit and, is higher than the head. It is continued distally in the body of the Humerus by the crest of the greater tubercle. The lesser tubercle of the Humerus is found on the medial side, it is not as high or as large as the greater tubercle. Found between the two tubercles is the intertubercular groove which is where the origin of the tendon of the biceps brachii can be found. The neck of the Humerus is not distinct except caudally. The ridge extending to the caudal part of the greater tubercle is on the lateral surface of Humerus. Distally, it is thickened to form the deltoid tuberosity. The deltoideus inserts here. From this tuberosity the caudal part of the greater tubercle the ridge forms the prominent tricipital line. The lateral head of the triceps arises form this line.
At the distal end of the Humerus is the humeral condyle. The articular surface is divided unevenly by a low ridge. The large area medial to the ridge is the trochlea, which articulates with both the radius and ulna. There are both medial and lateral epicondyles with the lateral being smaller than that of the medial one and occupies the enlarged distolateral end of the Humerus proximal to the capitulum, which is a small articular area lateral to the ridge.
