1 66 Muffles of . [Book IX. 



pubis and ifchium. Its fibres converge tp a point, and 

 pafTmg outwards around the back part of the neck of 

 the os femoris, are inferted by a flrong tendon into the 

 inner and back part of the trochanter major, adhering 

 in their courfe to the capfular ligament of the thigh 

 bone. Its ufe is to roll the thigh bone obliquely out- 

 wards, and to prevent the capfular ligament from being 

 pinched. 



The mufcles placed at the pofterior part of the pel- 

 vis, and defigned for the motions of the lower extre- 

 mity are, the gluteus maximus, which forms the ex- 

 ternal layer, and arifes from the pofterior part of the 

 Ipine of the ileum, from the whole pofterior furface 

 of the os facrum, and from the pofterior facroifchiatic 

 ligament j defcending obliquely, it pafles over tl\e 

 trochanter major, is firmly connected to the tendinous 

 expanfions of the tenfor vagina? femoris, and is inferted 

 by a broad tendon into the upper and outer pare of the 

 linea afpera. The effect of this mufcle is to draw the 

 thigh backwards arid a little outwards. 



The gluteus medius forms another layer. It arifes 

 from the anterior fuperior fpinous procefs and the dor- 

 fum of the os ileum, and is inferted into the outer and 

 pofterior part of the trochanter major. Its ufe is to 

 draw the thigh outwards, and a little backwards, and 

 to roll it, efpecially when it is bended. 



The third layer confifts of four mufcles. 



The gluteus minimus arifes from the outer furface 

 of the os ileuiTi and the border of the great niche. It 

 is inferted into the upper and anterior part of the great 

 trochanter, and afiifts the former mufcle. 



The pyriformis arifes within the pelvis, from the an- 

 terior part of the os facrum, thence becoming narrower, 

 it paffes out of the pelvis along with the pofterior crural 

 nerve, below the niche in the pofterior part of the os 



ileum. 



