CHAPTEE IX. 



DISEASES OF BONES AND JOINTS. 

 DISEASES OF BONES. 



Inflammation of Bone. Because of close continuity, it is 

 highly improbable that inflammation attacks any one constituent 

 part of a bone. Thus, in periostitis there is always a certain 

 amount of osteitis, and in osteomyelitis it is usual for the perios- 

 teum to be sooner or later involved. 



Periostitis may be of a simple or a specific origin. Simple trau- 

 matic periostitis occurs most frequently in those bones which are 

 chiefly exposed to injury. Hence it is common in the tibia, which 

 is so liable to meet with blows or kicks. Moreover, acute infec- 

 tive periostitis also as a rule attacks those bones which may meet 

 with traumatism ; therefore the femur, the tibia, the radius, the 

 clavicle and the lower jaw are most generally affected. The 

 micro-organisms inducing the disease are generally conveyed to 

 the injured portion of the diaphysis by the blood stream, the 

 patient not infrequently having a small focus of suppuration 

 somewhere in the body, such as a boil or patch of impetigo con- 

 tagiosum. The inflammation as a rule starts in the diaphysis 

 not far from an epiphysis, and most usually near to that epiphy- 

 sis from which the bone chiefly grows in length, as for instance, 

 the proximal end of the tibia, the distal end of the radius and the 

 distal end of the femur, possibly owing to the greater vascularity 

 of the part. The inflammation is limited to the diaphysis 

 because of the close adhesion of the periosteum to the epiphyseal 

 cartilage. Therefore while the whole of the shaft of the bone 

 may perish from the fluid effused beneath the periosteum 

 depriving it of its blood supply, the epiphysis retains its vitality 

 because its enveloping periosteum is not stripped off, and its 



