Chap, xix.] THE HIP JOINT. 403 



by the tilting of the pelvis. In some cases of simul- 

 taneous disease in both hip joints that has been in- 

 differently treated, both thighs may remain ad ducted. 

 The limbs are unable, of course, to remedy their posi- 

 tion by the usual means, when the disease is double, 

 and consequently one limb is crossed in front of the 

 other, and the peculiar mode of progression known as 

 " cross-legged progression " is produced. 



6. The real shortening depends upon destructive 

 changes in the head of the bone, or to dislocation of 

 the partly-disintegrated head on to the dorsum ilii, 

 through yielding of the softened capsule and the 

 crumbling away of the upper and posterior margin of 

 the acetabulum. 



When hip disease commences in bone it usually 

 involves the epiphyseal line that unites the head of 

 the femur to the neck. This line is wholly within 

 the joint, and the epiphysis that forms the head unites 

 with the rest of the bone about the eighteenth or 

 nineteenth year. 



When the bone is primarily involved the posi- 

 tion of flexion and abduction with e version may 

 not be observed at all, there being no effusion at first 

 into the joint. In such cases the limb becomes at 

 once flexed and adducted, and this posture is probably 

 due solely to muscular spasm, and to an attempt 

 to prevent the head of the femur from pressing 

 against the acetabulum, and so causing pain. 



It is well known that patients with hip disease 

 often complain of pain in the knee. This referred 

 pain may be so marked as to entirely withdraw 

 attention from the true seat of disease. Thus I once 

 had a child sent to my out-patient department with a 

 sound knee carefully secured in splints, but without 

 any appliance to the hip, which was the seat of a 

 somewhat active inflammation. This referred pain is 

 easy to understand, since the two joints are supplied 



