436 THE INFERIOR EXTREMITY 



It seems possible, however, that in these cases adduction is 

 present from the beginning, and that the attitude is due to a 

 reflex stimulation of the adductor muscles by the obturator 

 nerve, which helps to supply the joint (p. 411). With the thigh 

 flexed and adducted, lateral rotation would result in the tighten- 

 ing of the ilio-femoral ligament. The limb, therefore, becomes 

 rotated medially, and in this position the ligament is slackened 

 to its furthest extent. As a result of the adduction of the 

 diseased limb, the sound limb is abducted to maintain their 

 parallelism, and the pelvis is depressed to the sound side. This 

 necessitates a compensatory scoliosis, and the centre of gravity 

 takes up a position over the healthy limb. 



In this attitude the diseased limb appears to be shorter than 

 its fellow. If measurements show that the shortening is real, 

 then either a pathological dislocation has occurred or the femoral 

 neck has been eroded. In both cases the upper border of the 

 greater trochanter is found above Nelaton's line (p. 424). 



When extension by weight and pulley is used to undo the 

 deformity of flexion and abduction in tuberculous disease of 

 the hip-joint, the force is primarily applied in the long axis of 

 the deformed limb. As the deformity is slowly overcome the 

 pulley is gradually lowered and carried medially. To prevent 

 the extending force from simply increasing the downward tilt 

 of the pelvis on the affected side, a greater weight must be applied 

 to the sound limb. A perineal band extending to the top corner 

 of the bed on the diseased side acts as a fulcrum over which the 

 two weights pull, and the greater weight, being on the sound 

 limb, tends to restore the pelvis to its normal position and, at 

 the same time, to reduce the abduction of the affected limb. 



When the deformity consists of flexion and adduction, 

 weights only need to be applied to the affected limb, as the 

 pelvis is tilted upwards on that side. A perineal band to the 

 top corner of the bed on the sound side is used to provide a 

 fulcrum, and the normal position of the pelvis is gradually 

 restored. 



Surgical Approach to the Neck of the Femur. The 

 region of the greater trochanter and the neck of the femur may 

 be approached either by a vertical incision over the trochanter 

 or by a U-shaped incision (p. 415). 



The vertical incision is carried through the fascial insertion 

 of the glutseus maximus, exposing (i) the insertion of the glutseus 

 medius, proximally, (2) the postero-distal part of the trochanter, 



