416 



THE MUSCULAE SYSTEM. 



Piriformis (insertion) 



Glutseus inedius 

 (insertion) 



Obturator interims and 

 gemelli (insertion) 



Obturator externus 



(insertion) 



Quadratus feraoris 

 (insertion) 



Ilio-psoas (insertion) 



Glutaeus raaximus 

 (insertion) 



Adductor magnus 

 (insertion) 



Adductor brevis 

 (insertion) 



Pectineus (insertion) 



Vastus medialis 

 (origin) 



and the dorsum ilii just lateral to 

 the superior anterior spine, and 

 from the fascia covering its lateral 

 surface (Fig. 369, p. 415). 



Invested, like the glutaeus 

 maximus, by the fascia lata, it is 

 inserted, distal to the level of the 

 greater trochanter of the femur, 

 into the fascia, which forms the 

 ilio-tibial tract (p. 404). The 

 muscle is placed along the an- 

 terior borders of the glutaeus 

 medius and gluteeus minimus. 



Nerve - Supply. The superior 

 gluteal nerve from the sacral plexus 

 (L. 4. 5. S. 1.) ends in this muscle after 

 passing between the glutseus medius and 

 glutaeus minimus. 



Actions. It assists in the abduction 

 and rotation of the thigh ; and along 

 with the glutseus maximus, by its in- 

 sertion into the ilio-tibial tract, it helps 

 to support the knee-joint in the extended position. 



M. Glutaeus Medius. The glutaeus 

 medius arises from (1) the dorsum ilii, be- 

 tween the iliac crest and posterior gluteal 

 line above and the anterior gluteal line 

 below (Fig. 369, p. 415), and (2) the strong 

 fascia lata covering its surface anteriorly. 



It is a fan-shaped muscle, its fibres con- 



FIQ. 370. MUSCLE - ATTACHMENTS TO THE 

 POSTERIOR ASPECT OF THE PROXIMAL 

 PART OF THE LEFT FEMUR. 



verging to the greater tro- 

 chanter, to be inserted by a 

 strong, short tendon into the 

 postero-superior angle of the 

 greater trochanter, and into 

 a well-marked diagonal line 

 on its lateral surface (Fig. 

 370, and Fig. 372, p. 417). 

 A bursa is placed deep to the 

 tendon at its insertion. 



The muscle is partly super- 

 ficial, partly concealed by the 

 glutseus maximus. It covers 

 the glutseus minimus, and the 

 superior gluteal nerve and the 

 deep branches of the superior 

 gluteal artery. 



Nerve -Supply. The superior 

 gluteal nerve from the sacral plexus 

 (L. 4. 5. S. L). 



Actions. This muscle is a 

 powerful abductor and medial 

 rotator of the thigh. 



M. Glutaeus Minimus. 

 The glutaeus minimus arises, 

 under cover of the glutseus 



THE LUMBAB 



TRIANGLE 



OF PETIT 



Fascia lata 



GLUT^EUS MAXIMUS 



GRACILIS 



ADDUCTOR MAGNUS 



SEMIMEMBRANOSUS 



SEMITENDINOSUS Bt 



Sciatic nerve 



BICEPS (long 

 head) 



FIG. 371. THE RIGHT GLUTAEUS MAXIMUS MUSCLE. 



