MYOLOGY 113 



Relations. — Inferiorly, with the bone and superiorly, with the 

 gluteus medius. 



Action. — Abducts and pulls the thigh forward. 



Extensor Femoris (Fig. 24, No. 15). Location. — Anterior femoral 

 region. It is divided into two parts: the vastus extemus and the 

 crureus. 



Origin. — The vastus extemus (Fig. 24, No. 14) arises tendinous 

 from the base of the trochanter of the outer part of the femur and 

 from this point down the bone approximately to the condyle. 

 The crureus (Fig. 24, No. 13) originates by a tendon from 

 the anterior upper prominent rim of the trochanter, from this 

 point extending down the ai tero-exterhal part of the shaft of the 

 femur. 



Insertion.— Merges with the gluteus primus, and, by a fascia-like 

 arrangement, spreads over the front of the knee-joint inserts to the 

 patella and is also inserted into the crest of the tibia. 



Shape. — Large, fleshy. 



Relations. — ^Posteriorly, with the femur and anteriorly, with the 

 ^artorius. 



Action. — Extends strongly the leg upon the thigh. 



Vastus Intemus (Fig. 16, No. 3). Location. — Internal and lateral 

 side of the femur. 



Origin. — Fvom the postero-intemal part of the shaft of the femur 

 just below the head, and in a straight line extending down the femur. 



Insertion. — By a broad tendon alc5ng the thickened inner border 

 of the summit of the tibia. 



Shape. — Thick, long. 



Relations. — ^Anteriorly, with the bone; surrounded by the other 

 crural muscles. 



Action. — Extends the leg upon the knee; a powerful assistant of 

 the extensor femoris. 



Biceps Flexor Cruris (Fig. 17, No. D, i). Locaiiow. —Posterior 

 tibial region. 



Origin.— By a tendinous fascia from the post-acetabular ridge, 

 extending between the antitrochanter and the anterior point of the 

 insertion of the semitendinosus. 



Insertion. — To the tuberosity on the external part of the shaft of 

 the fibula a short distance below the head. 



Shape. — Large, rather cone-shaped with base directed upward. 



Relations. — ^Anteriorly, with the vastus extemus; posteriorly, with 



