PRINCIPLES OF VETERINARY SURGERY 85 



ease. The atrophy may be slow but it is always certain 

 and will vary according to the severity and the duration of 

 the lameness. If a limb remains absolutely inactive for a 

 long time the muscles may almost completely disappear, 

 leaving only their fibrous stroma and a few starved cells as a 

 trace of their former existence. With renewed activity re- 

 generation will' occur, slowiy^ perhaps, but always with cer- 

 tainty. Atrophy of the gluteals from subacute and chronic 

 affections of the hind legs, of the shoulder and pectoral mus- 

 cles from lamienesses in the fore extremities, of the masseters- 

 from lesions in the inferior maxillary, are so many examples 

 oi this form of atrophy in the large domestic animals. 



(3) Pressure. — If any part of the organism is submitted 

 to constant pressure not sufficiently severe to provoke necro- 

 sis, atrophy of the compressed part will result. The pressure 

 may be mechanical upon the surface of the body or that of 

 encroaching tumors upon certain internal organs. 



(4) Centric Paralysis. — The atrophies caused from cen- 

 tric paralysis are not common in animals, because they sel- 

 dom survive the primary afifection. The stroke 6f apoplexy 

 that is followed by a general unilateral atrophy is seMom 

 seen in animals because death occurs during the original 

 trouble or soon after, from complications. The muscles of 

 mastication and deglutition sometimes waste rather rapidly 

 from bulbar paralysis in the horse, and those of the hind ex- 

 tremities from a paraplegia of spinal origin, in the dog and 

 hog. Otherwise central lesions are of little import in the 

 study of atrophy of domestic animals. 



SYMPTOMS. — Atrophy is recognized by the small size 

 of the aiJected organ when compared with the normal. In 

 the muscles it appears as an excavation in the affected part, 

 exposing the skeletal apophyses. In the hips it gives the 

 animal the appearance of being "lop-sided," and exposes 

 prominently the angles of the ilium, the great trochanter, the 



