172 



THE SKELETON. 



forms the front of the pelvis, supports the external organs of generation, and has 

 received its name from the skin over it being covered with hair. 



The Ilium presents for examination two surfaces, an external and an internal ; 

 a crest, and two borders, an anterior and a posterior. 



External Surface or Dorsum of the Ilium (Fig. 120). The posterior part of this 

 surface is directed backward and outward ; its front part, downward and outward. 



Anterior superior 

 spine. 



GEMELLUS SUPERIOR. 



Spine of ischium. 



Sy Ilio-pectineal line 

 r, fv\f r (timber nut's LIGAMENT. 



RECTUS ABDOMINIS 



PYRAMIDALIS- 

 ADDUCTOR LONGUS 



GEMEULUS INFERIOR. 



FIG. 120. Right os innominatum. External surface. 



It is smooth, convex in front, deeply concave behind ; bounded above by the crest, 

 below by the upper border of the acetabulum ; in front and behind by the anterior 

 and posterior borders. This surface is crossed in an arched direction by three 

 semicircular lines the superior, middle, and inferior curved lines. The superior 

 curved line, the shortest of the three, commences at the crest, about two inches in 

 front of its posterior extremity ; it is at first distinctly marked, but as it passes 

 downward and backward to the upper part of the great sacro-sciatic notch, where 



