APPLIED ANATOMY. 



Reversed Luxations. In certain few cases, either from the peculiar character 

 and direction of the primary injury or from an ordinary anterior or posterior luxa- 

 tion becoming subsequently more widely displaced, there result what are known as 

 reversed luxations. They are of two kinds, reversed thyroid and reversed dorsal. 



Reversed Thyroid.- In a thyroid luxation the toes point forward ; if now the leg 

 is forcibly twisted until the toes point directly backward a reversed thyroid is pro- 

 duced (Fig. 521). In reducing it the head must be first rotated back to its original 

 thyroid position and then reduced by the usual methods. 



Reversed Dorsal. In a dorsal luxation the foot is inverted ; if now the leg is 

 forcibly twisted outward until the foot is everted, a reversed (or everted) dorsal luxa- 

 tion is produced (Fig. 522). To reduce it the leg must be rotated inward until the 

 head resumes its original position posteriorly and then it may be reduced by the usual 

 dorsal methods. In the production of both these reversed luxations the ligaments are 

 torn still more and the iliofemoral ligament may even be partially detached from its 

 insertion in the femur. 



The Ligamentum Teres. In complete luxations the ligamentum teres is 

 torn but it is not large enough to constitute an obstacle to reduction. 



Infolding of the Capsule or Muscle. Should the capsule be torn from its 

 attachment to the femur, it may prevent reduction by filling the socket and prevent- 



KIG. 521. Reversed thyroid luxation. (After Allis.) FIG. 522. Reversed dorsal luxation. (After Allis.) 



ing the entrance of the head. Fragments of muscle may act likewise. To clear 

 the socket Allis advises first, rotation to tighten the Y ligament and pressing the 

 head firmly in ; second, to rock the head backward and forward and so clear the 

 obstructing material out. 



To Release the Sciatic Nerve. If the sciatic nerve is caught around the 

 neck of the femur and cannot be otherwise released, Allis advises extending the leg 

 and cutting down on the nerve at the upper part of the popliteal space. It is then 

 grasped and pulled taut, this releases it from the neck and the thigh can then be 

 flexed and the head replaced : of course, if preferred, an incision can be made 

 directly down on the nerve at the hip. 



To Reduce a Dislocation Complicated by Fracture. To accomplish this 

 Allis advises first a trial of the usual direct method of traction and pressure on the 

 head and, if this fails, then while the head is held as near to the socket as possible by 

 an assistant the thigh is brought down and traction is made downward. 



Congenital Luxations of the Hip. In congenital luxations the acetabulum 

 may be shallow, the head deformed, and the neck somewhat twisted on its shaft. 

 These luxations are usually posterior. 



