224 



A MANUAL OF ANATOMY 



following structures : the small sacro- sciatic ligament at the tip, 

 the levator ani, coccygeus, and white line of the pelvic fascia on the 

 inner surface, and the gemellus superior along the lower border. The 

 external surface (back) supports, from within outwards, the pudic 

 nerve, internal pudic vessels, and nerve to the obturator internus. 



Crest and 

 Obliquus Interims Abdominis 



Transversalis Abdominis 



Quadratus Lumborum 



I Tuberosity 



Ligamentous Surface 



Erector Spinae 



Multifidus 

 Spinae 



Anterior Superioi 

 Iliac Spine 



Iliacu9 



Anterior Inferior 

 Iliac Spine 



Iliopectineal Line - 

 Psoas Parvus ~ 

 Ilio-pectineal 

 Eminence 



Obturator Groove 



Superior 

 Pubic Ramus 



Pubic Spine . 

 Pubic Crest 

 Pubic Angle 



Pubic Body 



Symphysis Pubis 



Levator Ani 

 Descending Pubic Ramu 



Posterior Superior 

 Iliac Spine 



Posterior Inferior 

 Iliac Spine 



Auricular Surface 



^ Great Sciatic Notch 



— — Coccygeus 



-Ischial Spine 



Levator Ani 

 Small Sciatic Notch 



Obturator Internus 



Tuber Ischii 



Transversus Perinaei 

 Ischio-cavernosus 



Ischial Ramus 



Fig. IJ2.— The Right Os Innominatum (Internal View). 



Below the spine is the small sciatic notch, which is covered by car- 

 tilage in the recent state for the play of the tendon of the obturator 

 internus. 



The tuberosity (tuber ischii) forms the thick dependent part, 

 and supports the body in the sitting posture. The upper border 

 limits inferiorly the obturator groove and small sciatic notch, and 



