INTRODUCTORY 



17 



FIG. 5. 



Vertebral Column. 



Hyoid. 



Clavicle. 



Simuim. 



Metacarpus, 



Metatarsus. 



Phalanges. 



THE SK K.I, ETON OF THE CAT. (LEFT SIDE ONLY.) 



THE HUMAN SKELETON. 



The skeleton of man (Fig. 6) closely resembles that of the cat ; 

 it is composed in general of the same bones, bearing the same names 

 and exhibiting the same features ; it varies slightly in the relative 

 proportions of its parts and in some minor details of structure. The 

 number of bones is smaller, which, as we shall see, is chiefly due to 

 the larger number of sesamoid bones in the cat. 



The most striking difference between the two skeletons is due to 

 the upright posture of man's body, and is associated with shortening 

 of the trunk, flattening of the thorax, broadening of the false pelvis, 

 straightening of the leg, and flattening of the foot. The arm is no 

 longer used in walking, and has gained a firm union to the trunk by 

 the articulation of the clavicle with the sternum. It has, therefore, a 

 wider range of function, with freer motion. The bones of the forearm 

 are capable of more complete rotation, permitting the hand to turn 

 palm forward ; and the movements of the thumb have become more 

 complex. A noteworthy difference lies in the form of the skull : 

 the increased development of man's brain has led to the subordina- 

 tion of the face to the cranium, to such an extent that the cranium 

 has assumed the shape of a globe, from the lower anterior part whereof 

 the face is suspended. 



The adult human skeleton consists of two hundred and fourteen 

 bones, whereof eighty are in the axial skeleton and one hundred and 



thirty-four in the appendicular. Some anatomists compute a greater 



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