208 PRINCIPLES OP TETERINABT SUEGEBT 



In complicated luxations tte symptoms peculiar to 'severe 

 injury of the surrounding soft parts, as well as fracture of 

 the dislocated bone, will be observed, such as external 

 wounds, rupture of tendons, laceration of bloodvessels large 

 and small, injury to more or less important nerves, open 

 joint, etc. 

 Describe the articular changes foUoiuing a luxation. 



There is invariably a rupture of the capsular ligament ; i 

 the surrounding tissues — that is, the ligaments, nerves, blood- " 

 vessels, tendons and muscles — are either stretched or torn. An 

 exception to this rule forms the dislocation of the patella, 

 sacro iliac articulation and the symphysis pubis. In the 

 so-called spontaneous or pathological dislocations, as seen in 

 dislocation of the patella, chronic arthritic changes are fre- 

 quently observed. As soon as luxation of a joint occurs and 

 the capsular ligament is torn a hemorrhage into and surround- 

 ing the joint, possibly including the adjacent connective tissue, 

 muscles, etc., takes place. The old socket is filled with bldod 

 and the dislocated bone is imbedded in a bloody area. If an 

 uncomplicated dislocation is reduced early, an almost normal 

 condition is obtained in due time, unless some of the lesions 

 undergo a faulty repair leading to subperiosteal formation of 

 bone or periarticular thickening. In old luxations the pro- 

 cess of repair is quite different. Let us suppose that the head 

 of the femur has left the cotyloid cavity. I have seen and 

 described in the current literature two such cases in mules 

 observed in South Carolina. In horses it is very rare, but 

 more common in dogs. The head of the femur in its new 

 position is in contact with a bony surface, against which it 

 presses. As a result of this pressure an osteitis and periostitis 

 results which in turn leads to formation of bone around 

 the head of the femur, and a new bony socket, even lined with 



