MUSCLES OF THE OS FEMORIS. 



379 



pelvis along with the posterior crural nerve, below the niche in 

 the posterior part of the os ilium, where it receiv^es a few fleshy 

 fibres. 



Inserted, by a roundish tendon, into the upper part of the 

 Fig. 99.* cavity, at the inner side of the 



root of the trochanter major. 



Use. To move the thigh a lit- 

 tle upwards, and roll it outwards. 



3. Gcmelli, 



Arise, by two distinct origins": 

 the superior from the spinous 

 p.ocess, and the inferior from 

 the tuberosity of the os ischium : 

 also, from the posterior sacro- 

 ischiatic ligament. They are 

 both united by a tendinous fleshy 

 membrane, and form a purse for 

 the tendon of the obturator in- 

 ternus muscle, which was for- 

 merly described. 

 Inserted, tendinous and fleshy, into the cavity at the inner 

 side of the root of the trochanter major, on each side of the 

 tendon of the obturator internus, to which they firmly adhere. 



Use. To roll the thigh outwards, and to preserve the tendon 

 of the obturator internus from being hurt by the hardness of 

 that part of the os ischium over which it passes ; also, to 

 hinder it from starting out of its place, while the muscle is in 

 action. 



* The deep muscles of the gluteal region. 1. The external surface of the 

 ilium. 2. The posterior surface of the sacrum. 3. The posterior sacro-iliac 

 ligaments. 4. The tuberosity of the ischium. 5. The great or posterior sacro- 

 ischiaiic ligament. 6. The lessor or anterior sacro-ischiatic ligament. 7. The 

 trochanter major. S. The gluteus minimus. 9. The pyriformis. 10. The 

 gemellus superior. 11. The obturator internus muscle, passing out of the 

 lesser sacro-ischiatic foramen. 12. The gemellus inferior. 13. The quadratus 

 femoris. 14. The upper part of the adductor magnus. 15. The vastus cxter- 

 nus. 16. The biceps. 17. The gracilis. 18. The semi-tendinosus. 



