LUXATION OP THE SHOULDER-JOINT. 765 



as possible, and care taken that the elbow-joint is moderately flexed, 

 so as to avoid a bad position afterwards. The lower part of the 

 limb should neither be fixed in a position of excessive supination nor 

 of pronation. In three to four weeks the animals commence to 

 place weight on the foot, and the bandage may then be removed. 

 At first the elbow-joint cannot be freely moved, but the amplitude 

 of movement gradually increases, especially if passive exercise be 

 given. In one case Frick attempted to fix the displaced condyle in 

 position with bone sutures, but the bone proved too friable and the 

 sutures tore out. Such operations, however, are perfectly practicable 

 provided careful antisepsis be observed ; the fragment may be fixed 

 in position with wire sutures, or, as in human practice, with ordinary 

 wood screws which have been silvered. 



Large animals, and notably horses, require slinging. After 

 prolonged slinging, however, the animal may show signs of acute 

 laminitis in the foot on which it stands. Despite the risk of 

 displacement, there is then no other course open but to allow the 

 animal to lie down, trusting that union may be sufficiently far 

 advanced to prevent bad consequences. The bed must be soft and 

 the box roomy. If the animal refuses to lie down, there is little 

 hope of recovery. 



III.— DISEASES OF THE SHOULDER-JOINT. 



The shoulder- joint, which in all domesticated animals is a ball-and- 

 socket joint, possesses a lax capsular ligament. The reinforcement of the 

 capsule in front by strong connective tissue and the protection afforded 

 by muscles, limit movement in the joint, and only allow moderate abduction, 

 adduction, and rotation, though considerable flexion and extension. 

 Flexion of the shoulder- joint is limited by the biceps, extension by the 

 caput muscles, abduction by the subscapularis, adduction by the antea 

 and postea spinati, so that the shoulder- joint in domesticated animals 

 possesses far less mobility than in man. The oval, nearly flat glenoid 

 cavity is much smaller than the head of the humerus. In swine and 

 carnivora, the size of the former is increased by a cartilaginous margin. 

 In these animals the shoulder-joint is also connected with the bursa 

 intertubercularis. 



(a) Luxation of the Shoulder- Jo int. — 'Complete displacement is 

 much rarer than in man, though it occurs both in horses, ruminants, 

 and dogs. In swine and carnivora, the position of the caput humeri 

 is ensured by the cartilaginous extension of the glenoid cavity ; in 

 the horse, by the tendinous biceps muscle. 



Luxation can generally be referred to excessive flexion of the 

 joint, and the humerus is, therefore, always thrust forwards and 



