214 ATLAS AND TEXT-BOOK OF HUMAN ANATOMY. 



Fig. 296. — The superficial layer of muscles of the anterior surface of the thigh. 



Fig. 297. — The muscles of the anterior surface of the thigh after removal of the sartorius. 



The inguinal ligament has also been removed. 



the anterior superior iliac spine, and at the junction of the upper and middle thirds of the thigh 

 becomes distinctly broader and is continuous with the iliotibial band (tract of Maissiat) of the 

 outer side of the fascia lata. Anteriorly the muscle is in immediate relation with the sartorius, 

 posteriorly with the glutaeus medius, and it partly covers the vastus lateralis. 



The muscle is supplied by the superior gluteal nerve and serves to increase the tension of the fascia lata. 



THE MUSCLES OF THE THIGH. 

 THE SARTORIUS. 



The sartorius (Fig. 296) is a very long, flat, narrow muscle running diagonally across the 

 anterior surface of the thigh, and is the longest muscle of the body.* It arises from the anterior 

 superior spine of the ilium in common with the tensor fasciae latas but in front of the latter muscle, 

 becomes considerably broader for a short distance after its origin, passes inward and downward 

 below the iliopsoas and upon the upper portion of the rectus femoris, covers the groove between 

 the vastus medialis and the adductors in the middle third of the thigh (see page 217), and reaches 

 the lower portion of the internal femoral region. In this situation it gradually becomes 

 narrower and is twisted so that the surface which was anterior in the upper portion of the thigh 

 now becomes internal. It then takes up a position beside the outer (anterior) margin of the gra- 

 cilis and becomes tendinous as it passes over the inner aspect of the articular capsule of the knee- 

 joint, and its flattened tendon runs above that of the gracilis to be inserted into the inner border 

 of the tuberosity of the tibia, being separated from the bone by the sartorial bursa. The tendon 

 of insertion forms the uppermost of the group of tendons known as the pes anserinus (see page 

 219). 



The sartorius is supplied by the femoral nerve. It aids in the flexion of the thigh and the extension of the lower 

 leg and acts as an internal rotator when the knee-joint is flexed. 



THE MUSCLES OF THE ANTERIOR SURFACE. 



The quadriceps femoris (Figs. 296 to 298, 301, and 302) consists of four different heads, 

 the most independent of which, the rectus jemoris, unites with the remainder only in the lower por- 

 tion of its course. This head passes over two articulations, while the remaining three are inti- 

 mately adherent with each other and extend over the knee-joint only. 



The rectus femoris (Figs. 296 to 298) is a long, thick, decidedly spindle-shaped muscle, 

 which is situated in the anterior femoral region, lying for the most part immediately beneath the 

 deep fascia. It arises by a short, strong, bifurcated tendon (Fig. 298), one part of which comes from 

 the anterior inferior spine of the ilium and pursues the same direction as that of the muscle 



♦The sartorius also possesses the longest muscular fasciculi in the body. 



