SHOULDER LAMENESS. 
521 
in the horse and clog at least, is still able to support weight, but again 
collapses when the weight is removed. The body load is better sustained 
so long as the radial nerve remains unaffected, but there is difficulty in 
advancing the foot. When contraction occurs in the triceps muscles, 
the leg, from the elbow downwards, is continuously fixed in extreme 
extension. This position is retained even during movement. 
Prognosis and course. The prognosis must be based on general 
principles, as our knowledge of this lameness is still very incomplete. 
As would be expected from its cerebral origin, spastic paralysis of the 
brachial plexus in dogs generally does badly. 
Treatment is similar to that of radial lameness. Massage, which 
improves nutrition, and prevents atrophy of muscle, is of more use than 
drugs. 
IX.—SHOULDER LAMENESS. 
Besides those above described, other lesions occur in the shoulder 
region, some of which evade even the most careful examination, and 
cannot be exactly diagnosed, or their results foretold. Lameness is the 
sole symptom, and for want of clearer knowledge these conditions have 
been included under the general term “ shoulder lameness.” As the chief 
muscles for the movement of the limb are found in the shoulder region, 
it is not surprising that these lamenesses show a certain agreement in 
symptoms. They are almost always marked by lameness when the 
limb is carried, i.e., movement 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, in speaking of each 
condition, we shall go more fully into these points. The following are 
some of the forms of shoulder lameness :— 
(1) Disease of the shoulder-joint and its surroundings. As a rule, 
this consists in chronic inflammation, which cannot be directly recognised 
by clinical means. Arthritis chronica, with erosion of cartilage and 
periarticular exostoses, is met with in old horses. In cattle and dogs 
rheumatic diseases of the shoulder-joint occur, and often produce lame¬ 
ness. Sometimes passive movements of the shoulder, raising and 
lowering the foot, occasion pain, and by relaxing the muscles of the 
shoulder render 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 and biceps brachii. The synovial 
