380 MUSCLES OF THE THIGH. 



4. Quadratus Femoris, 



Arises, tendinous and fleshy, from the outside of the tuberosity 

 of the os ischium; and, running transversely, is 



Inserted, fleshy, into a rough ridge, continued from the root 

 of the large trochanter to the root of the small one. 



Use. To roll the thigh outwards. 



Muscles situated on the Thigh. 



These are called muscles of the leg ; and consist of one, on 

 the outside; two on the inside; four, before; and four, behind. 



Previous to the description of the muscles that are situated 

 on the thigh and leg, it is necessary to take notice of a broad 

 tendinous fascia or sheath, (aponeurosis of the lower extremi- 

 ties^) which is sent off from the back and from the tendon of 

 the glutei and adjacent muscles. 



It is a strong thick membrane on the outside of the thigh 

 and leg ; but, towards the inside of both, it gradually turns 

 thinner, and has rather the appearance of cellular substance 

 than a tendinous membrane. A little below the trochanter 

 major, it is firmly fixed to the linea aspera ; and, farther 

 down, to that part of the head of the tibia that is next the 

 fibula ; where it sends off the tendinous expansion along the 

 outside of the leg. 



It serves to strengthen the action of the muscles, by keeping 

 them firm in their proper places while in action, particularly 

 the tendons that pass over the joints where this membrane is 

 thickest, and it gives origin to a number of. the fleshy fibres of 

 the muscles. 



On the outside is, 



Tensor Vagina Femoris, 



Arises, by a narrow, tendinous, and fleshy beginning, from 

 the external part of the anterior superior spinous process of the 

 os ilium. 



Inserted, a little below the trochanter major, into the inner 

 side of the membranous fascia which covers the outside of the 

 thigh. 



