MUSCLES OF THE PELVIS. 673 



the sacrum and coccyx, and from the great sacro-sciatic 

 ligament, by fleshy and aponeurotic fibres. Its fibres are 

 collected into distinct fasciculi, presenting a thick, strong, 

 and large quadrangular fleshy mass of muscle, of a rough 

 and coarse appearance, descending obliquely downward 

 and forward to terminate in a broad, thick tendon, which 

 is inserted into the upper third of the linea aspera, also into 

 a rough ridge, leading from this line to the trochanter, and 

 into the fascia lata over the vastus externus. The fasci- 

 culi of this muscle are separated by processes of the fascia 

 fernoris, and it almost entirely covers all the muscles on 

 the back of the pelvis together with the origin of the ham- 

 string muscles. A large bursa is observed between the 

 tendon and vastus externus, and a third where this muscle 

 glides over the tuberosity of the ischium. 



Function. To extend the thigh and rotate it outward ; 

 also to support the trunk in the erect position. 



Turn down the gluteus maximus upon the thigh, and 

 we expose the gluteus medius, gluteus minimus, pyriformis, 

 gemelli, obturator, and quadratus femoris. 



The gluteus medius (Fig. 212) is a triangular, flat mus- 

 cle, having its anterior portion uncovered by the gluteus 

 maximus. It arises from the outer edge of the whole of 

 crest of the ilium, except its posterior part, by fleshy and 

 aponeurotic fibres ; also from the dorsum of the ilium, be- 

 tween its crest and semicircular ridge, and from the strong 

 fascia which covers it. It is inserted by a broad, thick ten- 

 don, into the upper and outer part of the trochanter major, 

 and into a portion of the shaft of the bone. 



Function. To extend the thigh and turn it outward. A 

 bursa is seen between the tendon of this muscle and the 

 tendinous insertion of the rotators. 



The gluten minimus, (Fig. 212,) so named from being 

 the smallest of the three glutei, is seen by raising the last. 

 It arises from the dorsum of the ilium, between the semi- 

 circular ridge and the margin of the acetabulum, and ending 

 in a round, strong tendon, is inserted into the upper, ante- 

 rior portion of the trochanter major, having a bursa between 

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