282 DISEASES OF CATTLE. 



covers every part of the bone except at the joints and, second, from 

 within through the minute branches of blood-vessels, which pass into 

 the bones through holes (foramen] 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 gives strength and is more abundant in the shafts of long bones ; 

 and the cancellated softer tissue of the inside, which affords accommo- 

 dation to the blood vessels necessary for the nourishment of that part 

 of the structure. 



In shape bones are divided into three classes : long, flat, and irregu- 

 lar. The long bones are the ribs and those mostly found in the limbs, 

 the flat bones in the head, the shoulder and the pelvis, and the irregu- 

 lar in the spinal column and the bones of the head. 



DISEASES OF BONES. 



The diseased conditions found in bones are classified briefly as fol- 

 lows: Inflammation of the structure of the bones (ostitis), which may 

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

 bone affected, or maybe confined to only a portion of it; inflammation 

 of the covering of the bone (periostitis) ; formation of tumor or enlarge- 

 ment on the surface of a bone (exostosis), which is liable to occur in any 

 part of the bone covered with periosteum, and is a common result of 

 inflammation of that membrane, which, when it occurs in the neighbor- 

 hood of a joint and involves two or more bones, is likely to result in their 

 union (anchylosis). The inflammatory condition sometimes assumes an 

 ulcerated form (caries), which from interrupted nutrition of the part 

 deprived of* the blood necessary to its nourishment occasionally dies, 

 and becoming separated from the main portion of the bone, acts as a 

 foreign body (necrosis). Soft bones (mollities ossium) is the condition 

 found in young animals in which the proportion of inorganic or earthy 

 matter is too small to give the necessary stability, so that the bones, 

 particularly of the limbs, bend. Kickets or bending of the bones arises 

 from this condition. In some cases the long bones of the limb are too 

 weak at birth to support the weight of the animal, and temporary splints 

 carefully padded and wrapped on with soft bandages become necessary. 

 Hard bones (fragilitas ossium) is the condition opposite to that last 

 described, and occurs in old animals, where through deficiency of ani- 

 mal or organic matter the bones become unduly hard and brittle, ren- 

 dering them more liable to fracture and more difficult to unite when 

 such an accident occurs. With this little introduction, which seems 

 almost indispensable, we will proceed at once to the consideration of 

 accidents. 



SPRAINS. 



The most common accident occurring to bones and joints is a sprain 

 of the ligaments uniting the bones, or the tendons uniting the muscles 



