[Illustration: FIG. 74.--Dislocation into the vicinity of the Ischiatic Notch. Note relation of neck of femur to tendons of obturator and gemelli, "Dislocation below the tendon" (diagrammatic).]
#Dislocation on to the pubes# is a further degree of the obturator form (Fig. 71). It is usually produced by forcible hyper-extension and lateral rotation of the hip, such as occurs when the body is bent back while the thigh remains fixed.
The capsule is torn farther forward than in the other varieties, and the head rests on the horizontal ramus of the pubes against the ilio-pectineal line.
_Clinical Features._--There is marked eversion, flexion, and abduction, but the shortening is inconsiderable. The ilio-psoas and [inverted Y]-ligament are tense. The head of the femur may be felt in the groin, with the femoral vessels over, or to one or other side of it. There is sometimes pain and numbness in the distribution of the femoral (anterior crural) nerve. The prominence of the great trochanter is lost.
#Treatment of Dislocation of the Hip.#--For the reduction of a dislocation of the hip complete anæsthesia is necessary, and the patient should be placed on a firm mattress on the floor to give the surgeon the best possible purchase upon the limb. The surgeon grasps the ankle with one hand, while the other is placed behind the head of the tibia, the leg being held at right angles to the thigh. An assistant meantime steadies the pelvis by making firm pressure over the iliac crests.
As the chief obstacle to reduction is the tension of the ilio-femoral ligament, the first indication is to relax this structure by flexing the hip _to its fullest extent_.
In the _backward_ varieties (dorsal and sciatic) the [inverted Y]-ligament is relaxed by flexing the thigh upon the pelvis in the position of adduction. The thigh is then fully abducted, to cause the head of the bone to retrace its steps forwards towards the rent in the capsule; and at the same time rotated laterally to relax the rotator muscles. This combined movement tends also to open up the rent in the capsule. Finally, the limb is quickly extended to cause the head to enter the socket. This object is often aided by making vertical traction or lifting movements on the abducted and laterally rotated limb before extending.
