466 Diseases of Joints. 



There is a large cavity in the neck and great trochanter, 

 and it extends also into the head. The walls of the cavity are 

 partly formed by fibrous tissue, but at the lower, and upper 

 and inner ends there are remains of a caseous extension. At 

 the latter place the disease has penetrated into the upper 

 part of the head. The cartilaginous surface is apparently 

 unchanged. 



This has probably been a case where the bone disease 

 has led chiefly to external abscesses, with secondary and late 

 implication of the joint. G. C. 2014. 



7. 103. Tubercular Arthritis, chiefly involving- the Aceta- 

 bulum. — Bones forming the left hip-joint of a growing person 

 — macerated, illustrating the above. 



The cavity of the acetabulum is enlarged, and in several 

 places is perforated. Two portions of bone have been necrotic 

 and in process of separation — one at the junction of the 

 iliac and pubiC; and the other, a larger piece, at the junction 

 of the iliac and ischial portions of the acetabulum. The rest 

 of the acetabular surface is rarefied and eroded where it is not 

 perforated. The articular surface of the head of the femur 

 is also rarefied and rough, and the texture of the neck is 

 lightened. The angle between the neck and the shaft is in- 

 creased, a change often seen in femora of young, bed-ridden 

 patients. G. C. 1150. 



7. 104. Tubercular Arthritis, chiefly involving" Aceta- 

 bulum. — Left innominate bone and upper end of the femur 

 — macerated, illustrating the above. 



The upper part of the acetabulum is very irregular, and 

 at one sjiot is perforated by an aperture a quarter of an inch 

 in diameter. A large piece of bone at the top is necrotic, 

 and has been in process of separation, and similar pieces have 

 no doubt dropped out from the gaps in the neighbourhood. The 



