ANTERIOR FEMORAL REGION. 243 



VASTUS EXTERNUS. 



(Fe iuoro-rotuletis Externus.) 



(PL. III. 35.) 



Situated on the outer side of the I'ectus femoris, this muscle 

 is broad, thick, flattened laterally, and semi-ovoid, extending 

 downwards and forwards ; it is fleshy, with strong tendinous 

 intersections. 



Origin. — From the external and part of the anterior aspects 

 of the shaft of the femur, and from the base of the trochanter 

 major downwards. 



Insertion. — To the upper and outer part of the patella ; or 

 it may join the rectus femoris. 



Relation. — Externally with the tensor fascia3 latse, and gluteus 

 externus ; internally with the rectus, crureus, and vastus internus, 

 with Avhich inferiorly it is intimately blended ; posteriorly with 

 the triceps abductor femoris and the femur. 



Action. — To extend the leg. 



VASTUS INTERNUS. 



{Feiaoro-Totuleus Internus.) 



(Fig. 76. I.) 



Corresponding to the externus, this muscle is situated on the 



inner side of the rectus femoris, the two forming a channel in 



which are lodged the rectus and crureus. It is semi-ovoid, and 



fleshy, becoming tendinous at its insertion. 



Origin. — From the neck of the femur, its antero-internal 

 surface, and the trochanter internus. 



Insertion. — To the upper and inner side of the patella. 

 Relation. — Externally with the rectus ; internally with the 

 sartorius, pectineus, psoas magnus, iliacus, adductor magnus, and 

 crural fascia. 



Action. — To extend the leg. 



CRUREUS. 



(Femoro-rotuleus Medius.) 



Situated below the rectus, and between the two vasti, this 

 muscle is small, cylindrical, fleshy, and tendinous at its extremi- 

 ties ; it is separated from the vasti with difficulty. 



