SHOULDER LAMFNESS. 341 



the trunk, may not be of serious import and may readily yield to 

 treatment, or even recover spontaneousl}^ and without interference, the 

 condition is quite changed when a case of tearing of the flexor brachii, 

 or of its tendons as they pass in front of the articulation, occurs, or, 

 what is still more serious, if there is inflammation or ulceration in the 

 groove over which this tendon slides, or upon the articular surfaces 

 or their surroundings, or periostitis at any point adjacent. 



Causes. — The frequency of attacks of shoulder lameness is not diffi- 

 cult to account for. The superficial and unprotected position of tlie 

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

 in fact it performs, render it both subjectivelj^ and objectively preemi- 

 nently liable to accident or injury. It would be difficult, 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. 



Symptoms. — Some of the symptoms of shoulder lameness are pecul- 

 iar to themselves, and yet the trouble is frequentl}^ 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 espe- 

 cially 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 pathological 

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

 plishment, 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. "\'^Tien in motion the two upper bony levers — the shoulder 

 blade and the bone of the upper arm — are reduced to nearly complete 

 immobility and the walking is performed by the complete displace- 

 ment of the entire mass, which is dragged forward without either 



