362 GENERAL ANATOMY. 



ly, been more differently arranged. They are distinguished 

 into articular and non-articular. The former will be described 

 as we proceed. 



The non-articular apophyses are somewhat rough. Their 

 size and their very diversified form allow them to be divided 

 into three kinds. Some, which are long and projecting like 

 a branch or a bony ramification, bear the name of branches, 

 processes, and apophyses, properly so called. 



Others, which are shorter and thicker, bear the name of 

 protuberances, tuberosities, and tubercles. 



The others, which are elongated, narrow, and little protrud- 

 ing, bear the name of crests, ridges, and lines. 



The synonymy of these different kinds of eminences is very 

 complicated and difficult. They are generally designated each 

 by names derived from trivial and rather loose comparisons, 

 sometimes also by names derived from their situation, their 

 size, their direction, and their uses. 



Their general use is that of affording insertion to ligaments 

 and tendons. 



578. The external cavities of the bones are, like their emi- 

 nences, distinguished into articular and non-articular. It is 

 of the latter only that we have to speak here. 



Of these cavities, some traverse, and others do not traverse, 

 the substance of the bone. Of the latter, some have a widened 

 entrance, sloped in all directions. These are fossae, fossettes, 

 and digital impressions. The others have the bottom wide, 

 and the entrance narrow, and are lined by the mucous mem- 

 brane, and filled with air. These are sinuses, and when they 

 are divided into several cavities, cells, or cellules. Others are 

 elongated, narrow, more or less deep. These are called fur- 

 rows, channels, meatuses, and grooves. The cavities of this 

 latter kind, when they exist on the edge of bones, bear the 

 name of notches or incisions. 



Of the cavities which traverse the bones from side to side, 

 some follow the shortest course, through a thin bone, and are 

 holes, slits, or fissures, others follow a longer and variously 

 contorted course, and are canals, conduits, &c. 



Sometimes several bones unite to form a cavity, as the skull 



