BONES: DISEASES AND ACCIDENTS. 263 



brane that covers e\'ery part of the. bone except the articular surface 

 of the joints; and, secondly, from within through the minute 

 branches of blood vessels which pass into the bones through holes 

 (foramina) on their surface and are distributed in the soft structure 

 (medulla) of the inside. The structure of the bone is divided into 

 two parts — the compact or hard material of the outside, which gi\es 

 strength and is more abundant in the shafts of long bones, and the 

 cancellated, softer tissue of the inside, which affords accommodation 

 to the blood \-essels necessary for the nourishment of that part of 

 the structure. 



In shajie, l)ones are divided into three classes — long, flat, and short. 

 The long bones are the ribs and those mostly found in the limbs; the 

 flat bones are found in the head, the shoulder, and the joelvis; the 

 short bones in the spinal column and in the lower portions of the 

 limbs. 



With this little introduction, which seems almost indispensable, we 

 will proceed at once to the consideration of diseases of bones, for they 

 undergo diseased processes like any other living tissue. 



OSTEITIS. 



Inflammation of the compact structure of bones (osteitis) may be 

 either acute or chronic, and may involve the whole extent of the bone 

 afl^ected or may be confined to only a portion of it. This inflamma- 

 tion results from injury, such as concussion, laceration, or a crushing 

 bruise; also from specific influences, as in actinomycosis (lumpy jaw) 

 or cases of foul foot. The latter affection frequently involves the 

 bones, and for this reason the pastern is the most frequent seat of 

 osteitis. There is dull pain on pressure and a painful swelling of 

 bone when pus is present. Suppuration may involve the overlying 

 soft tissues, causing an abscess, which may finally break through the 

 skin. The inflammatory condition sometimes assumes an ulcerated 

 form (caries) or from interrupted nutrition of the part deprived of 

 the blood necessary to its nourishment may cause death of a large 

 section of bone (necrosis) ; this dead fragment (sequestrum), becom- 

 ing separated from the main portion of bone, acts as a foreign body. 



Ty^eatment. — This consists in resting the affected part and in giving 

 vent at the earliest possible moment to whatever pus may be present. 

 Free drainage should then be maintained. Apply dressings of lactic 

 acid or inject with 5 per cent zinc-chlorid solution and pack with 

 tampons of cotton soaked in antiseptic solutions. A laxative to keep 

 the bowels moving freely is the only internal treatment necessary. 



PERIOSTITIS. 



This disease is an inflammation of the external covering of bone 

 (periosteum) and is usually produced by wounds, pressure, or crush- 



