PRACTICAL CONSIDERATIONS : THE HIP-JOINT. 



579 



that cavity at the point where it emerged. The whole movement is made up of the 

 successive steps of flexion, adduction, abduction, eversion, and extension. 



In reduction of anterior dislocations some of the steps of the procedure are 

 reversed, — i.e., the movement consists of flexion, abduction, adduction, inversion, 

 and extension, in the order mentioned. The inner limb of the ligament is then of 

 chief importance as a fulcrum. The objection to this method in both cases is the 

 danger to the sciatic nerve, already pointed out, and also to the femoral vessels. 



AUis's methods of reduction are intended to avoid this danger. He endeavors 

 to cause the head to retrace accurately the path by which it left the socket. In a 

 posterior dislocation the 



head has usually left the Fig. 397. 



acetabulum in a down- 

 ward direction, has fallen 

 below the socket, and has 

 passed outward around 

 the edge of the acetabu- 

 lum to its new position ; 

 the limb has then fallen 

 into partial extension by 

 its own weight. Thus 

 there are three steps, 

 which, naming them in 

 their reverse order, are : 

 3, extension ; 2, motion 

 outward ; i, motion 

 downward. The steps 

 of his method are accord- 

 ingly : I, flexion ; 2, ro- 

 tation of the head inward 

 (by carrying the leg 

 out), placing it where it 

 was immediately after 

 leaving the acetabulum ; 

 3, lifting — to bring the 

 head to the level of the 

 socket — and extension 

 (using the ilio-femoral 

 ligament, which then be- 

 comes tense, as a ful- 

 crum, and aided by the 

 upward pressure of the 

 thumbs of an assistant), 

 carrying the head up- 

 ward into the socket. 



In the reduction of 

 anterior dislocations the 

 anatomical and mechani- 

 cal principles involved 

 are the same. In those 

 dislocations the head has 

 left the socket by tearing 



the capsule on its inner margin, and has passed inward to the pubo-ischiatic plane ; 

 the limb representing the other end of an inflexible lever must move in the opposite 

 direction, or outward ; and as it falls a little downward by its own weight, the head 

 rises slightly. To restore it, reversing these steps, flex to a perpendicular, lowering 

 the head somewhat ; make traction on the limb, drawing the head outward ; and 

 then, the head being fixed by the hands of an assistant, adduct and extend the thigh, 

 causing the head to enter the socket. 



By these methods reduction of dislocation complicated with fracture of the 



1^, 



Luxation of the head of the femur into the obturator foramen. 



