PERSONAL APPEARANCES IN HEALTH AND DISEASE. 39 



Any account of the changes of form undergone by the 

 body would be incomplete, even in a general sketch like 

 this, without some mention of those partial but frequently 

 troublesome and permanent distortions which arise from 

 affections of the joints. All the structures entering into 

 the composition of a joint may at one time or another be 

 so altered as to lead to deformity. Thus, the synovial 

 sac (see p. 17) may become distended with fluid, and 

 give the joint a swollen rounded appearance, concealing 

 entirely the natural prominences of the extremities of the 

 two bones that form it : or the fibrous ligaments surround- 

 ing the ends of the bones and keeping them together 

 may be swollen and altered from inflammation, and lead 

 to similar swelling and alteration of the other soft parts, so 

 as completely to disguise the joint and render it more or 

 less fixed. Or these same ligaments may be shortened and 

 changed by disease so as to cause one bone to pass beyond 

 the other, and produce what is called a dislocation, or the 

 dislocation may take place from a violent injury, without any 

 disease of the joint, and lead to marked deformity of the 

 limb at the part of the displacement. Or the ends of the 

 bones themselves may be enlarged and the seat of changes, 

 which permanently cause an alteration in the shape. 



As to simple dislocation from injury, it may be 

 remarked that in some joints this cannot take place 

 unless bone or ligament be broken, so intimate is the 



