342 



occurs, or, wliat is still more serious, if tlierc is inflammation or ulcer- 

 ation in the groove over whicli this tendon slides, or upon the articular 

 surfaces or their surroundings, or periostitis at any point adjacent. 



The frequency of attacks of shoulder lameness is not difficult to 

 account for. The sux)erficial and unprotected position of the part, 

 and the numerous movements of which it is capable, and which in 

 fact it performs, render it both subjectively and objectively preemi- 

 nently liable to accident or injury. It would be difacult, nor would 

 it materially avail, to enumerate all the forms of violence by which 

 the shoulder may be crippled. A fall, accompanied by powerful con- 

 cussion; a violent muscular contraction in starting a heavily loaded 

 vehicle from a standstill; a misstep following a quick muscular effort; 

 a jump accompanied by miscalculated results in alighting; a slip on 

 a smooth, icy road; balling the feet with snow; colliding with another 

 horse or other object — indeed, the list might be indefinitely extended, 

 but it would be without profit or utility. Some of the symptoms of 

 shoulder lameness are peculiar to themselves, and yet the trouble is 

 frequently mistaken for other affections — navicular disease more often 

 than any other. The fact that in both affections there are instances 

 when the external symptoms are but imperfectly defined, and that 

 one of them especially is very similar in both, is sufficient to mislead 

 careless or inexperienced observers and to occasion the error which is 

 sometimes committed of applying to one disease the name of the other, 

 erring both ways in the interchange. The true designation of patho- 

 logical lesions is very far, at times, from being of certain and easy 

 accomplishment, and owing to the massive structure of the parts we 

 are considering this is especially true in the present connection. And 

 still there are many cases in which there is really no reasonable excuse 

 for an error in diagnosis by an average practitioner. 



Shoulder lameness will of course manifest itself by signs and 

 appearances more or less distinct and pronounced, according to the 

 nature of the degree and the extent of the originating cause. We 

 summarize some of these signs and appearances: 



The lameness is not intermittent but continued, the disturbance of 

 motion gauging the severity of the lesion and its extent. It is more 

 marked when the bones are diseased than when the muscles alone 

 are affected. When in motion the two upper bony levers, the shoul- 

 der blade and the bone of the upper arm, are reduced to nearly 

 complete immobility and the walking is performed by the complete 

 displacement of the entire mass, which is dragged forward without 

 either flexion or extension. The action of the joint below, as a natural 

 consequence, is limited in its flexion. In many instances there is a 

 certain amount of swelling at the point of injury— at the joint, or more 

 commonly in front of it, or on the surface of the spinatus muscle. 

 Again, instead of swelling there will be muscular atrophy, though 

 while this condition of loss of muscular power may interfere with 



