[Illustration: FIG. 14.—Muscles and ligaments of the arm and forearm of a hen. _A._ External view. 1, Expansor secundarium. 2, Tensor patagii longus. 3, Tensor patagii brevis. 5, Brachialis anticus. 6, Pronator longus. 7, Supinator brevis. 8, Extensor indicis brevis. 10, Scapulo-humeralis. _B._ Internal view. 9, Ligamentum laterale cubiti internum. ] The _ligamentum transversum_ spreads out between the head of the ulna and the radius, thus uniting the two bones, and limiting supination (Fig. 15, No. 1). =Ligaments of the Carpal Joint.=—The carpal joint is made up of the ulna, radius, the two carpal bones and the metacarpus. There are two strong _ligamenta obliqua carpi ulnaris_ which extend from the processus styloideus of the ulna to the tuberculum posterius carpi ulnaris of the os carpi ulnaris. The _ligamentum posticum ulnare carpi ulnaris_ extends from the processus styloideus of the ulna to the os carpi ulnaris. [Illustration: FIG. 15.—Ligaments of the arm and forearm of a hen. _A._ The scapulo-coraco-humeral articulation. 1, Proximal end of the humerus. 2, Articular head of humerus. 3, The coracoid. 4, Proximal end of the clavicle. 5, Tendon of pectoralis tertius. 6, Tendon of pectoralis secundus. 7, Opening or foramen triossium through which the tendon of the elevator of the wing passes. (Pectoralis secundus.) 8, Broken end of scapula. _B._ 1, Ligamentum transversum. 2, Ligamentum laterale cubiti externum. 3, Ligamentum annulare radii. 4, Ligamentum cubiti teres. 5, A portion of the ligamentum capsulare cubiti. 6, Distal extremity of humerus. 7, Ulna. 8, Radius. _C._ Muscles of the outside surface of the arm. 1, Tensor patagii longus. 2, Extensor digitorum communis. 3, Tensor patagii brevis. 4, Anconeus. 5, Flexor carpi ulnaris. 6, Biceps. 7, Triceps. 8. Deltoid. 9, Brachialis anticus. 10, Flexor metacarpi radialis. 11, Extensor ossis metacarpi pollicis. 12, Extensor metacarpi radialis longior. 13, Extensor indicis longus. ] The _ligamentum ulnare carpi radialis_ is a short ribbon-like ligament which passes over the above-mentioned ligaments and is attached to the inner surface of the os carpus radialis. The _ligamentum ulnare carpi radialis internum_ is a strong ligament which originates on the inner part of the elbow. It extends to the upper rim of the base of the main digit. The _ligamentum radiale carpi radialis externum_ originates on the outside of the head of the middle digit and inserts to the superior tuberculum carpi radialis of the radius. The _ligamentum carpi radialis internum_, a short ligament, extends from the inside of the head of the main digit to the inner rim of the carpi radialis. The _ligamentum carpi interosseum_ is located between the carpal bones.