PELVIC LIMBS 691 



adductor and vastus interims muscles. Of its superior two branches, 

 the outer branch is low and wide, and has the appearance of a wide 

 rough area for the attachment of the pectineus muscle, while the inner 

 branch is not so prominent, and marks the upper part of the posterior 

 boundary of the area of origin of the vastus internus. Near the 

 middle of the linea aspera is the foramen for the nutrient artery of 

 the shaft, which pierces the compact tissue of the bone obliquely toward 

 the upper extremity. 



The triangular space at the upper part of the posterior surface 

 between the two branches of the linea aspera is free from muscular 

 attachment. At the lower inner part of the surface is the triangular 

 area of insertion of the semimembranosus. 



The lower part of the shaft gradually increases in width and passes 

 without a sharp line of demarcation into the lower extremity. The 

 flattened area above the condyles forms the popliteal space. 



The Lower Extremity is widest below and behind, and its greatest 

 transverse diameter is twice as great as the transverse diameter of the 

 shaft. Its anterior surface is on the same plane as the anterior sur- 

 face of the shaft, but its posterior surface is prolonged backward. It 

 appears to be directed slightly inward, away from the long axis of 

 the shaft, but this is due more to the obliquity of the lines upon the 

 extremity than to the obliquity of the extremity itself. The lower ex- 

 tremity consists of two condyles, separated in front and below by the 

 shallow trochlear surface for the patella, and below and behind by the 

 deep intercondyloid notch. The condyles have in general the same 

 shape, and differ only slightly in detail. 



The external condyle is longer and wider than the internal.- 

 When viewed from the side (Fig. 530) the anterior border is seen to 

 leave the straight line of the anterior surface of the shaft, and, curving 

 downward and backward, to form an arc of a large circle the centre 

 of which lies on the external border near the junction of the shaft 

 with the lower extremity. This curve is continued until the lower 

 point of the condyle is reached, beyond which the curve alters, and, 

 as a posterior border of the condyle, describes the half of a circle 

 whereof the centre is at the most prominent point of the side. The 

 curve ends abruptly, and the upper part of the posterior border passes 

 upward and forward into the external border of the shaft as a sharp 

 ridge, known as the supracondyloid ridge. About on a level with the 



