body on the thigh; the psoas bends the lumbar spine forward 

 and laterally. 



Psoas parvus makes tense the iliac fascia. 



Pyriformis, obturator internus, and gemelli are external 

 rotators after extension, abductors if the thigh is flexed. 



Quadratus femoris is an external rotator, and may assist 

 adduction. 



Obturator externus is an external rotator; may flex and adduct. 



THE THIGH MUSCLES 



These are arranged in three sets anterior, posterior, and 

 internal with superficial and deep layers, the former passing 

 over two joints, the latter over one. 



The Anterior Femoral Region 



1. M. tensor vaginas femoris (tensor fascise) lies in a groove 

 between the gluteus medius, rectus, and sartorius. Origin, 

 anterior part of the external lip of the iliac crest, notch between 

 the two spines, fascia over the gluteus medius; insertion, be- 

 tween the two layers of the fascia lata 3 or 4 inches below the 

 great trochanter, and from the insertion fibers are prolonged 

 into the iliotibial band; the outer of the two laminae covers 

 the muscle; the deeper is connected with the origin of the 

 rectus. 



2. M. Sartorius (tailor muscle). Origin, anterior superior 

 spine of the ilium and small part of the notch immediately 

 below; insertion, inner surface of the tibia near the tubercle, 

 sending an expansion from the upper border to the capsule, 

 one from the lower border to the fascia of the leg, and one to 

 the tibia behind the tendons of the gracilis and semitendinosus. 

 It is oblique at first, then vertical to the knee, and then curves 

 forward. 



M. Quadriceps Femoris, p. n. Largest muscle of the body, 

 four parts closely united, (a) Rectus femoris, iiv a straight 

 line from the pelvis to the patella. Origin, by two heads; 

 anterior one from the anterior inferior spine, and posterior 

 from the impression just above the acetabulum; they join 

 at an angle of 60 degrees close below the acetabulum; the 



