BONES: DISEASES AND ACCIDENTS. 



By V. T. Atkinson, V. S. 

 [Revised in 1904 by John R. Mohler, V. M. D.] 



Some knowledge of the skeleton is advisable to facilitate the study 

 of diseases of bones and the accidental injuries to which they are 

 exposed. The skeleton of the adult ox is made up of the following 

 number of bones : 



Spinal column 45 



Head 28 



Chest 27 



Shoulder 2 — Ion each side. 



Arm 2 — 1 on each side. 



Fore arm 4 — 2 on each side. 



Fore foot 40 — 20 on each side. 



Pelvis 2 — Ion each side. 



Thigh 2— Ion each side. 



Leg 6 — 3 on each side. 



Hind foot 38 — 19 on each side. 



Total 1!)G 



Without attempting to burden the reader with the technical names 

 and a scientific classification of each, it appears desirable to describe 

 some of the characteristics of forms in general, and of a few classes 

 into which they may be divided, leaving the sj^ecial study of in- 

 dividual bones to the illustrations of the skeleton (PI. XXV), which 

 will serve better than any amount of writing to fix in the mind of the 

 reader the location, relation, and function of each one. In early fetal 

 life the place of bone is supplied by temporary cartilage, which 

 gradually changes to bone. For convenience of study, bones may be 

 said to be composed of a dense form of connective tissue impregnated 

 with lime salts and contain two elementary constituents — the organic, 

 or animal, and the inorganic, or earthy. In young animals the former 

 predominates; with increasing years the relative proportions of the 

 two change, so that when advanced age is reached the proportion of 

 inorganic far exceeds the organic. The gi'adual change with ad- 

 vancing years from organic to inorganic has the effect of rendering 

 the bone harder and more brittle, and though it is stronger the repar- 

 ative jDrocess is slower when injury does occur. 



The bones are nourished in two ways: First, from the outside 

 through their covering, called the periosteum — the thin strong mem- 

 brane that covers every part of the bone except the articular surface 



269 



