94 



BONES OF THE LOWER LIMB. 



pubis, and ischium. These three portions meet at the acetabulum, in the 

 formation of which they all take part ; and the os pubis and ischium also 

 meet on the inner side of the obturator foramen. 



Fig. 85. RIGHT Os INNOMTNATUM 



FROM THE DORSAL ASPECT. ^ 



1, anterior superior spinous pro- 

 cess ; 2, anterior inferior ditto ; 3, 

 posterior superior ; 4, posterior in 

 ferior spinous process ; 5, crest of 

 the ilium ; 6, surface occupied by 

 the gluteus medius muscle above 

 the superior curved line ; above 3, 

 is a rough surface to which the 

 gluteus maximus is attached ; 7, 

 surface between the superior and 

 inferior curved lines occupied by 

 the gluteus minimus ; 8, groove 

 above the acetabulum, occupied by 

 the posterior tendon of the rectus 

 femoris ; 9, superior ramus of tho 

 pubis and pectineal eminence ; 1 0, 

 crest and spinous process of the 

 pubis; 11, place of meeting of the 

 descending or inferior ramus of the 

 pubis with the ascending ramus of 

 the ischium ; 12, spine, and 13, 

 tuberosity of the ischium ; 14, car- 

 tilaginous surface of the acetabu- 

 lum ; and 15, synovial depression 

 and pit for the round ligament ; 



16, thyroid or obturator foramen ; 



17, greater, and 18, lesser sciatic 

 notches ; between the acetabulum 

 and the ischial tuberosity is seen 

 the groove occupied by the obtu- 

 rator externus muscle. 



10 



U 



The ilium constitutes the superior expanded portion of the bone, and 

 forms a part of the wall of the acetabulum by its inferior extremity. Above 

 the acetabulum it is limited anteriorly and posteriorly by margins which 

 diverge at right angles one from the other, and superiorly by an arched 

 thick and extensive border, the crista ilii. The crest is curved like the letter 

 f, the anterior extremity pointing slightly inwards and the posterior out- 

 wards ; its surface is broadest in its anterior and posterior thirds, it is rough 

 for the attachment of muscles, and on it may be distinguished an external 

 and internal lip and an intermediate space. The anterior extremity of the 

 crest forms a projection forwards called the anterior superior spine of the 

 ilium, and, separated from it by a concave border, and placed immediately 

 above the acetabulum, is another eminence called the anterior inferior spine : 

 the projecting posterior extremity of the crest forms the posterior superior 

 spine, and separated from it by a notch is the posterior inferior spine, below 

 which the posterior border of the bone is hollowed out into the great sciatic 

 notch. The external surface, or dorsum of the ilium, concavo-convex from 

 behind forwards, presents, close to the posterior extremity of the crest, a 

 roughness of some extent, to which the gluteus maximus muscle is attached, 

 and is traversed by two rough arched lines, one of which, the superior curved 

 line, beginning in front at the upper border of the bone, about an inch and 

 a half from its anterior extremity, arches backwards to the upper part of 

 the great sciatic notch, while the other, the inferior curved line, shorter 



