22 CLINICAL APPLIED ANATOMY. 



their situation exposes them to risk of injury. The numerous 

 articular vessels which ^supply an epiphysis in active growth 

 render it more vulnerable than the diaphysis with its solitary 

 artery. The vessels which supply an epiphysis also supply the 

 adjacent joint ; hence disease of the two is often associated, but 

 the joint may also be invaded by direct extension from the 

 epiphysis. In adults after the period of rapid epiphysial growth 

 has passed the synovial membrane rather than the bone is likely 

 to be the part attacked. 



The vascular cancellous tissue of the bodies of the vertebrae, 

 the head of the tibia, the condyles of the femur, the neck of the 

 femur, the lower end of the humerus and of the olecranon, is 

 favourable to a tuberculous deposit. The bones of the tarsus, in 

 which cancellous tissue is abundant, and which are peculiarly 

 exposed to slight strains and injuries during locomotion, are often 

 the site of tuberculosis. Those exposed to the greatest strain 

 are said to be most frequently attacked, the order of liability 

 being os calcis, first metatarsal, astragalus, cuboid, scaphoid, 

 and cuneiform. The proclivity of the inner longitudinal arch 

 is very obvious. The relation of the tar sal bones to the synovial 

 cavities of the foot determines the subsequent direction of the 

 tuberculous process. In this respect disease of the scaphoid bone 

 is serious, since it may extend to both the anterior and posterior 

 segments of the tarsus. When the carpus is attacked the fact 

 that the synovial sac between the bones of the first row and the 

 radius is shut off from the second row of joints is important. 

 The joints of the second row communicate with the carpo-meta- 

 carpal joint by a channel between the trapezoid and os magnum. 



The cancellous tissue of the flat bones of the skull, of the 

 finger bones, of the acetabulum, and of the glenoid fossa of the 

 scapula affords a good nidus for the tubercle bacillus. 



Necrosis is a natural result of inflammation in an unyielding 

 tissue like bone. In very acute tuberculous inflammation of 

 the ends of the long bones a wedge-shaped sequestrum may 

 form, pointing to embolism of an artery as the origin of the 

 process. 



