216 SKELETON. 



mity of the os femoris is beset with foramina, large and small, 

 for the passage of vessels and the attachment of fibres. 



The body of the os femoris begins at the trochanters, and 

 terminates in the condyles. It is slightly bent, so as to present 

 the convexity of the curve forwards. Its size is gradually di- 

 minished to the middle; it then begins to enlarge, and continues 

 to augment till it terminates in the large inferior extremity. 

 The body is very nearly round, and departs from that figure 

 only on its posterior face, where an elevated rough ridge is 

 found, occupying the superior two>thirds of the bone, and called 

 the linea aspera. The linea aspera begins broad, rough, and 

 flat, on a level with the trochanter minor; it narrows as it de- 

 scends, and becomes, at the same time, more elevated. Its 

 lower extremity bifurcates into two superficial, slightly marked 

 ridges, one on ea'ch side, which may be traced into the poste- 

 rior extremity of its corresponding condyle. Between these 

 ridges the surface of the bone is flattened. In the whole course 

 of the linea aspera, an internal and an external margin is very 

 obvious. The superior half of the latter is occupied by the in- 

 sertion of the gluteus magnus, and the remainder by the origin 

 of the biceps flexor cruris. This margin also gives origin to 

 the vastus externus. The internal margin of the linea aspera 

 is mostly occupied by the insertion of the triceps adductor, and 

 by the origin of the vastus internus. 



In the linea aspera, near the middle of the bone, is the canal 

 for the nutritious artery, which slants upwards : occasionally 

 one or more canals, besides, are found in it for the same pur- 

 pose. 



The texture of the os femoris is compact in its body. Its 

 extremities are cellular, with the exception of a thin lamina 

 forming their periphery : the cylindrical cavity in its middle, 

 like that in all the other long bones, is reticulated. The ossa 

 femorum approach each other very closely at their inferior ex- 

 tremities, but are widely separated at their superior, in conse- 

 quence of the length of their necks, and of the distance of the 

 acetabula from one another. 



