520 



THE MUSCLES AND FASCIA 



Inner Hamstring 

 tendons. 



SARTORIUS. 



GRACILIS. 

 SEMITCNDINOSUS. 

 SEMIMEMBRA 



NOSUS. 



Outer 



Hamstring 



tendon. 



FIG. 387. Muscles of the hip and thigh. 



The Obturator interims (m. 

 obturator interims} (Figs. 387 

 and 388), like the preceding 

 muscle, is situated partly within 

 the cavity of the pelvis, and 

 partly at the back of the hip- 

 joint. It arises from the inner 

 surface of the anterior and ex- 

 ternal wall of the pelvis, where 

 it surrounds the greater part 

 of the obturator foramen, being 

 attached to the descending ramus 

 of the os pubis and the ramus of 

 the ischium, and at the side to 

 the inner surface of the innomi- 

 nate bone below and behind 

 the pelvic brim, reaching from 

 the upper part of the great 

 sacrosciatic foramen above and 

 behind to the obturator fora- 

 men below and in front. It 

 also arises from the inner surface 

 of the obturator membrane ex- 

 cept at its posterior part, from 

 the tendinous arch which com- 

 pletes the canal for the passage 

 of the obturator vessels and nerve 

 and to a slight extent from the 

 obturator layer of the pelvic 

 fascia, which covers it. The 

 fibres converge rapidly, and are 

 directed backward and down- 

 ward, and terminate in four or 

 five tendinous bands, which are 

 found on its deep surface; these 

 bands are reflected at a right 

 angle over the inner surface of 

 the tuberosity of the ischium, 

 which is grooved for their recep- 

 tion; the groove is covered by 

 cartilage, and lined with a syno- 

 vial bursa (bursa m. obturatoris 

 interni). The muscle leaves the 

 pelvis by the lesser sacrosciatic 

 foramen; and the tendinous 

 bands unite into a single flat- 

 tened tendon, which passes hori- 

 zontally outward, and, after 

 receiving the attachment of the 

 Gemelli, is inserted into the fore 

 part of the- inner surface of the 

 great trochanter in front of the 

 Obturator externus. 



