Comparative anatomy of the humerus

The Humerus is the long bone of the arm, articulating with the scapula to form the shoulder and the radius and ulna to form the elbow. In situ, it lies obliquely along the ventral thorax and is more horizontal in larger species.
The head of the humerus comprises greater and lesser tubercles, separated by an intertubercular groove through which runs the tendon of the biceps brachii. The shaft of the humerus takes on a characteristically twisted shape via a groove carrying the brachialis and radial nerve. Laterally, the deltoid tuberosity is palpable through the skin and connects to the head of the humerus via a ridge and merges distally with the crest of the humerus. Distally, the humerus culminates in a condyle which articulates to form the elbow.

In large animals, it meets the radius via a trochlea

In dogs and cats, it articulates with the ulna medially via a trochlea and the radius laterally via a capitulum

Caudally, all species show an olecranon fossa which articulates with the olecranon of the ulna

At the distal end of the humerus a small hole may be seen connecting the olecranon fossa caudally with the radial fossa cranially. This is the supratrochlear foramen. No structures pass through it.

Medial and lateral epicondyles provide attachment for flexors and extensors of the carpus and digits.
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Видео Comparative anatomy of the humerus канала Veterinary Anatomy