424 Diseases of Joints. 



SERIES 7. DISEASES OF JOINTS. 



I. ABNORMALITIES IN GROWTH OR DEVELOPMENT. 



7. 1. Cong-enital Anchylosis of the Superior Radio-ulnap 



Joint. — Eight radius and ulna — macerated, illustrating the 

 above. 



The bones are in the position of complete pronation. The 

 upper end. of the radius is fused with the adjacent part of the 

 ulna, the head of the radius being represented by a small knot 

 projecting from the outer side of the greater sigmoid cavity. 

 There has therefore been no capitellar surface, and probably no 

 capitellum. The bones are separated below. The shaft of 

 the ulna is thin, and. its bony ridges are sharp and not in their 

 usual position. 



This specimen is stated to have been taken from a child. 

 From this fact, as well as from the absence of indication of 

 previous disease, it has been considered a congenital mal- 

 formation. B. C. II. M. 52. 



n. CHANGES PRODUCED BY CONDITIONS AFFECTING THE 

 NUTRITION OF JOINTS. 



7. 2. Deg"eneration of Cartilag-e in Old Ag'e. — Patella and 

 rectus femoris tendon from an old person — in spirit, illustrating 

 the above. 



The central portion of the articular cartilage of the patella 

 is broken up into fibrill£e, which resemble the pile of velvet. 



