MUSCLES WITHIN THE PELVIS. 347 



Inserted, tendinous, into -the trochanter minor of the os 

 femoris ; and fleshy into that bone, a little below the same 

 trochanter. 



Use. To bend the thigh forwards ; or, when the inferior 

 extremity is fixed, to assist in bending the body. 



4. lliacus Interims. 



Arises, fleshy, from the transverse process of the last vertebra 

 of the loins, from all the inner lip of the spine of the os ilium, 

 from the edge of that bone between its anterior spinous process 

 and the acetabulum, and from most of the hollow part of the 

 ilium. It joins with the psoas magnus, over the pubis, where 

 it begins to become tendinous ; and is 



Inserted along with it on the trochanter minor. 



Use. To assist the psoas in bending the thigh, and to bring 

 it directly forwards. 



N. B. The insertion of the two last muscles should not be 

 traced till the muscles of the thigh are dissected. 



Muscles situated within the Pelvis. 

 Of these there are two pair. 



1. Obturator Internus, 



Arises from more than one half of the internal circumference 

 of the foramen thyroideum, formed by the os pubis and ischium, 

 and from the upper part of the plane of the ischium, where it 

 joins the ilium. Its inner face is covered by a portion of the 

 levator ani ; and appears to be divided into a number of fascic- 

 uli, which unite, and form a roundish tendon, that passes out 

 of the pelvis, between the posterior sacro-ischiatic ligament and 

 tuberosity of the os ischium ; where it passes over the capsular 

 ligament of the thigh bone, it is enclosed as in a sheath, by the 

 gemini muscles. 



Inserted, by a round tendon, into the large pit at the root of 

 the trochanter major. 



Use. To roll the os femoris obliquely outwards. 



N. B. The insertion of this muscle should not be traced 

 until the muscles of the thigh, to which it belongs, are dissected. 



