696 MAMMALIAN ANATOMY 



above and the anterior surface toward the student, the head will be 

 on the side to which the bone belongs. 



Articulation. --The femur articulates with the innominate, the 

 tibia, and the patella. 



Muscular Attachments. The following muscles are attached to 

 the femur : 



To the greater trochanter, the glutens medius, the pyriformis, the 

 glutens minimus, the obturator internus, the obturator externus, the 

 gemelli, the gluteus maximus, and the quadratus femoris. 



To the lesser trochanter, the psoas and the iliacus. 



To the shaft, the gluteus quartus, the gluteus maximus, the quad- 

 riceps extensor (formed of the vastus externus, the vastus internus, 

 and the crureus), the tensor vaginse femoris, the pectineus, the a.d- 

 ductor, and the semimembranosus. 



To both condyles, the gastrocnemius. 



To the outer condyle, the popliteus and the extensor longus digi- 

 torum. 



Blood-Supply. The shaft of the femur is pierced by the nutrient 

 artery arising from the femoral artery. 



Ossification. The femur is developed from five centres : one for 

 the shaft, one for the head, one for the lower extremity, one for the 

 greater trochanter, and one for the lesser trochanter (Fig. 534). 



In some specimens examined, the lower extremity appeared to ossify 

 from two distinct centres, one for each condyle. 



VARIATIONS IN THE FEMUR. 

 VARIATIONS IN SIZE. 



The measurements of the femur are taken as follows : 



The maximum length is the distance from a median point on a 

 line drawn transversely to the top of the head or the greater tro- 

 chanter, whichever is highest when the bone is held vertically, to the 

 lowest point on the articular surface for the tibia. 



The width of the upper extremity is the greatest transverse 

 diameter from the convexity of the head to the outer edge of the 

 greater trochanter. 



The width at the condyles is the greatest transverse diameter 

 between the prominences of the condyles. 



