Chap, xix.] DISLOCATIONS OF THE HIP. 409 



violence, but the accident is, I believe, illustrated by 

 no actual specimens. Mr. Henry Morris has collected 

 five cases of separation of the epiphysis of the great 

 trochanter. This separation, if complete, could hardly 

 avoid being intracapsular in part, since the capsule is 

 attached to the anterior superior angle of the 

 trochanter itself. 



Dislocations of the hip. These injuries are 

 comparatively rare, on account of the great strength 

 of the articulation, and when they occur in a healthy 

 joint are always the result of a considerable degree of 

 violence. A dislocation of the hip may be congenital, 

 or may be spontaneously produced by muscular 

 efforts, as shown in a few rare cases, or may be the 

 result of disease of the articulation. We are, how- 

 ever, now concerned only with "regular" dislocations, 

 the result of violence. 



Varieties. The head of the bone may be found 

 displaced in four directions, producing the four regular 

 dislocations of the hip. In two the head of the femur 

 is posterior to a line drawn vertically through the 

 acetabulum, and in the other two it is found anterior 

 to that line. 



(1) Backwards and upwards. Head rests upon 

 ileum, just above and behind acetabulum. The "dis- 

 location upon the dor sum ilii" (2) Backwards. Head 

 rests upon ischium, and, as a rule, about on a level 

 with the ischial spine. The " dislocation into the 

 sciatic notch" (3) Forwards and downwards. Head 

 rests on thyroid foramen. The " obturator or thyroid 

 dislocation" (4) Forwards and upwards. Head 

 rests upon the body of the pubes, close to its junction 

 with the ileum. The " dislocation upon the pubes." 



The above arrangement represents also the order 

 of frequency of these luxations, No. 1 being the most 

 common dislocation of this part, and No. 4 the most 

 rare. 



