48 



THE BONES AND JOINTS. 



body can be distinguished, which takes part in the formation of the 



acetabuhim (a). The hinder and broadest part of the bone is joined 



to the corresponding portion of its fellow by ligament ; anteriorly the 



two diverge, bounding a cone-shaped cavity, the pelvis. The suture, 



by which the body of the iliac bone is united with the ischiatic 



and pubic bones, runs from above downwards through the middle of 



the acefabulnm (Fig. 42, 

 Fig. 41. 



Fig. 



Pelvisof Rana esculeiita, 

 from below, nat. size. 



a Acetabulum. 

 U Iliac bone. 

 p Pubic bone. 



from 2j through the ace- 

 iahnlum to is). Inferiorly 

 and in front the united 

 Uia form a prominence 

 (<s), which represents the 

 ■v/)iiijJ/f/.vs OSS. jnih. of 

 man. The expanded por- 

 tions of the ilium rest 

 directly over the articu- 

 lar cavity by means of 

 a somewhat constricted 

 part or root. The ala is 

 a sabre-like bone, with 

 the sharper, more convex 

 border directed upwards ; 

 the more concave, thicker 

 border downwards. The two surfaces, 

 of which the inner is grooved, are 

 directed respectively inwards and outwards. 

 The broader part of the blade springs 

 directly from the neck or root (at il'), and 

 at this end of the sharp ccmvex border 

 is a process, process, s/ijj., from which 

 the tendon of the m. vastus ejieniits arises. 

 The anterior end of the blade is a hol- 

 low cylinder, containing cartilag*e, mov- 

 ably articulated to the transverse process 

 of the last vertebra or sacrum. 



2. The ischia, ossa iscliii [is), are irre- 

 gular, four-cornered plates of bone, united 

 together by the whole extent of their inner surfaces. The vertical 

 plate formed by the union of the two bones takes only a very 

 small share in the formation of the articular cavity. Above, it has 

 a somewhat sharp border, continued with the ilium into a process 



Pelvis of Rana esculcntit, left side, 



twice nat. size. 

 a Acetabulum. 

 d Upper sharp border. 

 U Iliac bone. 

 W Superior process. 

 is Ischium. 

 is' Tuber ischii. 

 /> Os pubis. 



*• Inferior process of the ilium. 

 V Lower border of same. 



