248 VASTUS INTERNUS CRUREUS. 



The RECTUS (straight) muscle is fusiform in its shape and bipenniform 

 in the disposition of its fibres. It arises by two round tendons, one from 

 the anterior inferior spinous process of the ilium, the other from the upper 

 lip of the acetabulum ; and i$ inserted by a broad and strong tendon, into 

 the upper border of the patella. It is more correct to consider the patella 

 as a sesaraoid bone, developed within the tendon of the rectus ; and the 

 hgamentum patellae as the continuation of the tendon to its insertion into 

 the tubercle of the tibia. 



Relations. By its superficial surface with the gluteus medius, psoas 

 and iliacus, sartorius ; and, for the lower three-fourths of its extent, with 

 the fascia lata. By its deep surface with the capsule of the hip joint, the 

 external circumflex vessels, crureus, and vastus internus and externus. 



The rectu^ must now be divided through its middle, and the two ends 

 turned aside, to bring clearly into view the next muscles. 



The three next muscles are generally considered collectively under the 

 name of triceps extensor cruris. Adopting this view, the muscle surrounds 

 the whole of the femur, excepting the rough line (linea aspera) upon its 

 posterior aspect. Its division into three parts is not well defined ; the 

 fleshy mass upon each side being distinguished by the names of vastus 

 internus and externus, the middle portion by that of crureus. 



The VASTUS EXTERNUS, narrow below and broad above, arises from 

 the outer border of the patella, and is inserted into the femur and outer 

 side of the linea aspera, as high as the base of the trochanter major. 



Relations. By its superficial surface with the fascia lata, rectus, biceps, 

 semi-membranosus and gluteus maximus, a synovial bursa being inter- 

 posed between it and the latter. By its deep surface with the crureus and 

 femur. 



The VASTUS INTERNUS, broad below and narrow above, arises from 

 the inner border of the patella, and is inserted into the femur and inner 

 side of the linea aspera as high up as the anterior intertrochanteric line. 



Relations. By its superficial surface with the psoas and iliacus, rectus, 

 sartorius, femoral artery and vein and saphenous nerves, pectin eus, ad- 

 ductor longus, brevis, and magnus, and fascia lata. By its deep surface 

 with the crureus and femur. 



The CRUREUS (crus, the leg) arises from the upper border of the patella, 

 and is inserted into the front aspect of the femur, as high as the anterior 

 intertrochanteric line. When the crureus is divided from its insertion, a 

 small muscular fasciculus is often seen upon the lower part of the femur, 

 which is inserted into the pouch of synovial membrane, that extends up- 

 wards from the knee joint, behind the patella. This is named, from its 

 situation, sub-crureus, and would seem to be intended to support the 

 synovial membrane. 



Relations. By its superficial surface with the external circumflex 

 vessels, the rectus, vastus internus and externus. By its deep surface with 

 the femur, the sub-crureus, and synovial membrane of the knee joint. 



fictions. The tensor vagina? femoris renders the fascia lata tense, and 

 slightly -inverts the limb. The sartorius flexes the leg upon the thigh, and, 

 continuing to act, the thigh upon the pelvis, at the same tim carrying the 

 leg across that of the opposite side, into the position in which tailors sit ; 

 hence its name. Taking its fixed point from below, it assists the extensor 

 muscles in steadying the leg, for the support ofUhe trunk. The other four 

 muscles have been collectively named quadriceps extensor, from their 



