THE INNOMINATE BONE. 



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ilium to the sacrum, separating the true pelvis below from the false above. All of 

 the ilium above this line, except a small part posteriorly, is a smooth, shallow con- 

 cavity, the iliac fossa,'^ which contains the iliac muscle. It ends in front in a groove 

 between the anterior inferior spine of the ilium and the ilio-pedineal eminence,^ a 

 swelling above the inner part of the acetabulum made by both the ilium and the 

 pubis at their point of meeting. The bone is very thin at the middle of the fossa. 

 The lower half of the inner surface of the ilium may be subdivided into two very 

 dissimilar parts. The front one, forming the wall of the true pelvis, opposite a part 



Fig. 352. 



Middle gluteal line 



External lip 



Latissimus dor si 



Superior 

 gluteal line 



Gluteus 

 niedius 



Post. sup. spine 



POSTERIOR BORDER — 



Post. inf. spine 



Pyriformis 



GREAT SACRO-SCIATIO NOTCH 



Body of ischium 



GentfUits superior 

 Spine of ischium 



LESSER SACRO-SCIATIC NOTCH 



Gemellus inferior 



TUBEROSITY 



Sentitendinosiis and biceps 



Semimembranosus 

 Quadratus femoris 



Obliquus externus 



Obliquus internus 



Tensor fas' 

 cite later 



Ant. sup. spine 

 Sat tortus 

 Ghiteus minimus 



ANTERIOR BORDER 



Inferior gluteal line 

 Ant. inf. spine 

 Rect u s femoris 



^ Reflected tendon 



of rectus 



Articular surface 

 Nonarticular surface 



SUPERIOR RAMUS 



Pectineu^ 



Obturator crest 



SPINE 



Adductor longus 



NFERIOR RAMUS 



Gracilis 

 Adductor brevis 



Cot\Ioid notch 



Obturatof externus 



ISCHIAL RAMUS 



Adductor tnagnus' 

 Right innominate bone, outer aspect. 



of the socket and above the sciatic notch, is smooth ; the posterior is rough. The 

 latter presents anteriorly the rough and pitted auricular surface'^ corresponding to 

 that of the sacrum. A narrow depression, the pre-a7iicular groove, bounds this on the 

 smooth surface, receiving the fibres of the anterior sacro-iliac ligament. Behmd the 

 auricular surface is a rough area of a different character with an elevation at or below 

 the middle of the preceding surface. This area serves for the attachment of the 

 strong posterior sacro-iliac ligaments. Still farther back the bone has a smoother 

 finish where it gives origin to the erector spinae. The ilium has several large 



^ Fossa iliaca - Eminentia iliopectinea. '' Facias auricularis. 



