112 



ANATOMY AND PHYSIOLOGY 



Practical point. Observe the number of muscles for external 

 rotation and note that the usual position of the foot is with the 

 toes turned outward. 



FIG. 91. MUSCLES OF THE 

 THIGH. 



MUSCLES OF THE THIGH 

 Anterior 



On the front and the sides of the 

 femur are the muscles which extend the 

 Jeg^-four in number; they blend at their 

 insertion and therefore constitute a four- 

 headed muscle, the quadriceps femoris^ 

 They are the rectus jemons, the vastus 

 later alis, vastus medialis and the vastus 

 intermedius. 



Rectus femoris. Origin. The an^ 

 terior inferior spine pf tV>p j]jujn and the 

 upper border of the acetabulum. The 

 three vasti. Origin.' On the linea as- 

 pera and the three surfaces of the femur. 

 Insertion of the four. By one tendon 

 passing in front of the knee^joml L6""the 

 tubercle of me tibia. (It encloses the 

 patella and has been improperly called 

 the ligamentum patellae.) 



Action. They extend the leg as in 

 walking, or with great force in kicking; 

 these muscles also keep the patella in 

 place during various positions of the 

 knee. 



Nerve. Femoral. 



The sartorius. The longest muscle 



i, 2, Iliacus aftd psoas; 3, . _ ,- 



4, tensor fascia; lata;: 5, sar- in the body; it passes across the front 



. the quadriceps. Origin.-Thejmte- 



medialis; 9, gracilis; 10, ad- rior superior spine nf fh* ilnirn Inser- 



i r ~" ,.,. 



. me inner surface of the tibia, 



just below the head. 



Action.- Since it passes across to the medial side of the thigh, 

 and behind the medial epicondyle, it flexes the leg and at the 



