DISEASES OF HORSES 237 



cially is very similar in both, is sufficient to mislead careless or inex- 

 perienced 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 ex- 

 cuse 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 shoulder blade 

 and the bone of the upper arm are reduced to nearly complete im- 

 mobility and the walking is performed by the complete displace- 

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

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

 sequence, is limited in its flexion. In many instances there is a cer- 

 tain 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 

 perfect locomotion, it is not in itself usually a cause of shoulder 

 lameness. Sweenied shoulders are more often due to disease below 

 the fetlock than to affections above the elbow. 



During rest the animal often carries his leg forward, somewhat 

 analogous to the pointing position of navicular disease, though in 

 some cases the painful member drops at the elbow in a semiflexed 

 position. The backing is sometimes typical, the animal when per- 

 forming it, instead of flexing his shoulder, dragging the whole leg 

 without motion in the upper segment of the extremity. 



The peculiar manner in which the leg is brought forward in the 

 air for another step in the act of walking or trotting is in some in- 

 stances characteristic of injuries of the shoulder. The lameness also 

 manifests itself in bringing the leg forward with a circumflex swing- 

 ing motion, and shortening in the extension of the step. The foot 

 is carried close to the ground and stumbling is frequent, especially 

 on an uneven road. 



With the utmost scrutiny and care the vagueness and uncer- 

 tainty of the symptoms will contribute to perplex and discredit the 

 diagnosis and embarrass the surgeon, and sometimes the expedient is 

 tried of aggravating the symptoms by way of intensifying their sig- 

 nificance, and thus rendering them more intelligible. This has been 

 sought by requiring the patient to travel on hard or very soft ground 

 and compelling him to turn on the sound leg as a pivot, with other 

 motions calculated to betray the locality of the pain. 



