784 SHOULDER LAMENESS. 



appears chiefly or solely interfered with during the forward stride, 

 and the affected limb is advanced slowly and incompletely. The 

 lameness varies according to the position, nature, and extent of 

 the disease process ; and therefore under each condition these points 

 will be more fully noticed. 



(1) Disease of the shoulder-joint and its surroundings. As a 

 rule, this consists in chronic inflammation, which cannot be directly 

 recognized by clinical means. Arthritis chronica, with erosion of 

 cartilage and periarticular exostoses, is met with in old horses. In 

 cattle and dogs rheumatic disease of the shoulder-joint occurs, and 

 often produces lameness. Sometimes passive movements of the 

 shoulder, raising and lowering the foot, occasion pain, and by 

 relaxing the muscles of the shoulder make the head of the humerus 

 more prominent. Atrophy follows long-continued lameness. As 

 a rule, there is pain when weight is placed on the limb, and especially 

 when the animal is turned in short circles. 



In a horse which had suffered from chronic shoulder lameness, Siedam- 

 grotzky found great thickening of the anterior surface of the joint, and 

 chronic inflammation of the bursa intertubercularis. The synovial 

 membrane was thickened and covered with numerous thread-like 

 proliferations, and the articular surface of the scapula increased to the 

 extent of about an inch by a circular bony growth. The cartilage covering 

 the articular surfaces of the scapula and humerus was abraded. 



(2) Disease of the muscular tissues of the shoulder is sometimes 

 traumatic, sometimes rheumatic, in origin. External violence, or 

 violent falls or leaps, may produce inflammation of the shoulder 

 muscles. Gerlach erroneously assigned these conditions to the biceps, 

 but although we are not in a position absolutely to deny their 

 occurrence in this position, yet they are exceedingly rare. Nesbit 

 reported a case in which both biceps muscles were torn away from 

 the coracoid process. Inflammatory symptoms, such as increased 

 warmth, pain on pressure, or on extending the diseased muscles, 

 can almost always be detected on careful examination, but care and 

 judgment are required in order to avoid error. 



Most horses flinch under strong pressure on the shoulder, nor 

 is tenderness a constant symptom even in painful lamenesses, so 

 that it is quite erroneous to consider that it is simply a question of 

 unequal sensitiveness. Moreover, the affected spot has often been 

 made more sensitive by manipulation, or by the application of 

 irritants. On the other hand, inflammation occurs in single muscles, 

 like the levator humeri, and even in entire muscular groups, such 

 as the pectoral muscles, in consequence of bruises and sprains, and 



