32 THE NECTURUS 



the ilium, extends down the femur and is inserted by a 

 tendon on the proximal end of the tibia, acting as an ex- 

 tensor of the leg. Follow the muscle from the origin to 

 the insertion. 



Ilioextensorius 



The third muscle from the anterior border of the leg 

 is quite large. It originates at the base of the ilium pos- 

 terior to the origin of the iliotibialis, and extends along the 

 posterior border of the thigh. After passing over the 

 knee, it spreads out in an aponeurosis and joins the muscles 

 of the lower leg, where it serves as an extensor. 



Iliofibularis 



This muscle is posterior to the ilioextensorius and is 

 partially covered by it. It is a long, thin muscle that is 

 mostly covered by the more anterior elements. Lift the 

 ilioextensorius, find its origin and follow the muscle to 

 its insertion on the fibula. 



Cut through the iliotibialis and ilioextensorius in order 

 to find the origin of the two muscles. Posterior to the 

 puboischiofemoralis internus, are two slips of the same 

 muscle, both of which are shorter than the anterior slip. 

 Locate their insertion on the femur. The iliofibularis now 

 shows completely and its origin and insertion can be deter- 

 mined. 



MUSCLES OF THE LOWER LEG 



The muscles of the lower leg have a great similarity to 

 those of the anterior limb. Carefully dissect the muscles 

 of the back of the foot. 



Drawing 12. Prepare a drawing of the skeleton of the region for 

 use as a basis for the locations of the origins and insertions. 



