Chap. VI.] THE MUSCLES. 69 



The supinators turn the palm of the hand backwards, and, 

 when the elbow is flexed, upwards or into the supine position. 

 Tire flexors and extensors have long tendons, some of which 

 are inserted into the bones of the wrist, and some into the bones 

 of the fingers: they serve to flex and extend the wrist and 

 fingers. 



Muscles of the lower extremity. — These include the muscles 

 of hip, thigh, leg, and foot. The most important of these are : — 



Glutei or gluteal muscles. Tibialis anticus. Soleus. 



Posterior femoral. Extensors. Flexors. 



Anterior femoral. Peroneal. Tibialis posticus. 



Internal femoral. Gastrocnemius. 



If we compare the muscles of the shoulder and arm with 

 those of the hip and leg, we shall see that the anterior muscles 

 of the former correspond roughly with the posterior muscles 

 of the latter, the muscles of the hip and leg, however, being 

 larger and coarser in texture than those of the shoulder and 

 arm. 



The glutei, or three gluteal muscles, form the chief prominence 

 of the buttock. They are coarse in texture, and are largely 

 concerned in supporting the trunk upon the head of the femur, 

 and in bringing the body into the erect position when the 

 trunk is bent forwards upon the thigh. 



The posterior femoral or hamstring muscles cover the back of 

 the thigh. There are three of these muscles, — the biceps, the 

 semitendinosus, and the semimembranosus. The chief of these 

 is the biceps, and is somewhat analogous to the biceps covering 

 the front of the arm. The action of the hamstring muscles is 

 to flex the knee and to extend the hip. 



The principal anterior femoral muscles are the quadriceps and 

 sartorius. The quadriceps covers the front of the thigh, and 

 is analogous to the triceps covering the back of the arm; it is 

 the great extensor of the leg; it also flexes the hip, and antago- 

 nizes the action of the hamstring muscles. The sartorius, or 

 tailor's muscle, is a long, ribbon-like muscle, the longest in the 

 body: it crosses the thigh obliquely from its origin in the ilium 

 to its insertion in the tibia. It was formerly supposed to be 

 the muscle principally concerned in producing the posture 

 assumed by the tailor in sitting cross-legged, and hence its name. 



