BONES OF LOWER LIMB 43 



From these differences it will be seen that the true pelvis is 

 altogether more roomy in the female and the outlet wider, which 

 is necessary for the purposes of childbirth. 



The Femur is a long bone with a shaft, and two extremities. 

 It articulates above with the acetabulum of the os innominatum 

 and below with the head of the tibia and the patella. 



The Upper Extremity consists of a rounded head forming 

 half a sphere, which is joined to the shaft, at an angle of 127*5 

 degrees, by the neck, a stout bar of bone, an inch or more in 

 length. The cartilage-covered part of the head has a wavy 

 outline where it joins the neck, and just below the summit is a 

 small fossa for the insertion of the ligamentum teres. The two 

 trochanters of the femur are situated on the posterior aspect of 

 the upper end of the shaft, the great trochanter being placed 

 externally and the small trochanter internally. Where the neck 

 joins the shaft a distinct line is seen, the intertrochanteric line 

 in front, and behind where it is more prominent it is called the 

 intertrochanteric ridge (crista intertrochanterica) . Just above 

 the middle of this ridge is the quadrate tubercle. The great 

 trochanter overhangs the neck above, and in the depression thus 

 formed is found the digital fossa for the tendon of obturator ex- 

 ternus. On its external surface is an oblique line running from 

 above downwards and forwards. The small trochanter is a 

 rounded eminence confluent with the shaft below. 



The Shaft is cylindrical in shape and convex forwards, 

 increasing in size gradually from above downwards. At its 

 lower end it is flattened to support the condyles. The shaft is 

 smooth except on its posterior surface, where a narrow longitu- 

 dinal ridge is found the linea aspera. This has distinct inner 

 and outer lips, which separate inf eriorly, each passing down to 

 its own condyle and enclosing a smooth triangular space the 

 popliteal surface. Where the inner lip meets the condyle is a 

 small tubercle the adductor tubercle. 



The Lower Extremity of the femur is flattened and recurved 

 posteriorly to form two condyles, between them being the deep 

 intercondylic notch. In front they are united to form a smooth, 

 flat surface for the patella. The inner condyle is longer and 

 narrower than the outer one; but as the femur in its normal 



