OP THE BONES. 361 



parts. They are globular, tetrahedral, cuneiform, cuboidal, 

 or polyhedral. 



The mixed bones, ossa mizta, are those which partake of 

 the character of several kinds. They are numerous: the occi- 

 pital bone, the sphenoid bone, the temporal bone, the coxal 

 bone, the sternum. The ribs participate of the character of 

 the broad and short bones. The long bones themselves re- 

 semble the thick bones at their extremities. 



576. There are distinguished in the external conformation 

 of the bones, parts, or regions of their extent. 



In the single bones there are, in general, either an azygous 

 and median parts, and lateral parts, as the body and processes 

 of the sphenoid bone, the body and theapophysal masses of the 

 vertebrae, &c. or lateral parts only, united in the median line, 

 as the two halves of the frontal bone, &c. 



Many bones divide into parts or regions, determined by 

 their mode of formation or development. Thus, the hip bone 

 is divided into ilium, ischium, and pubis, the sphenoid bone, 

 the ethmoid bone, the temporal bone, &c. into several regions 

 equally distinct by the mode of their development. 



In other bones, the division into regions results solely from 

 the situation and uses of the parts. Thus, the outer surface of 

 the frontal bone is divided into an orbitar and nasal region, a 

 frontal region, &c. 



There are also admitted in the bones geometrical regions or 

 parts of their extent. Thus, there are distinguished and de- 

 scribed in the long bones, a body or central part and extremi- 

 ties; in the broad bones, faces, edges, and angles, &c. but these 

 terms are not strictly applied, for planes and angles are very 

 rare and imperfect in the organization. 



577. The bones present at their surface eminences and de- 

 pressions which are greatly diversified. 



The eminences of the bones are distinguished into epiphy- 

 ses and apophyses. The epiphyses have relation to the de- 

 velopment, and will be described when we speak of it. 



The apophyses are bony eminences, continuous with the 

 substance of the bones. They are extremely numerous and 

 highly diversified. Few objects in anatomy have, according- 



