444 BRANCHES OF INTEENAL ILIAC ARTERY. 



Th5 two tGrniinal branches of the obturator artery communicate with each 

 oth-r near the lower margin of the obtui-ator ligament, and anastomose with 

 branches of the internal circumflex artery. The external Ijranch also communi- 

 cates with offsets from the sciatic arteiy near the tuber ischii. 



Varieties. — The obturator artery frequently has its origin transferred to the 

 commencement of the epigastric artery, and sometimes to the extenial ihac at 

 its tennination. 



In iM'tl cases observed by R. Quain. the origin of the obturator arteiy varied 

 as follows. In the proportion of 2 cases out of 3, it arose from the internal iliac : 

 in 1 case out of oi, from the epigastric : in a very small number of cases (about 

 1 in 72), it arose by two roots from both the above-named vessels ; and in about 

 the same proportion, from the external iliac artery. 



Sometimes the obturator artery arises from the ejiigastric on both sides of the 

 same body, but in the majority of instances, this mode of origin of the vessel is 

 met with only on one side. 



"Wlien the obturator artery arises from the epigastric, it turns backwards into 

 the pelvis to reach the canal at the upper part of the thyroid foramen ; and in 

 this course it is necessarily close to the cniral ring, tlie opening situated at 

 the inner side of the external iliac vein, through which hernial protrusions 

 descend from the abdomen into the thigh. In the greater number of instances 

 the artery springs from near the root of the epigastric, and is directed backwards 

 close to the iliac vein, and therefore lies to the outer fide of the femoral ring ; 

 but in other instances, arising from the epigastric artery higher up, it occasionally 

 crosses over the ring, and curves to its inner side. It is when it takes this last 

 course tht.t the obturator artery is liable to be wounded in the oi)eration for 

 dividing the stricture in a femoral hernia. 



The anastomosis which normally exists between the obtiu'ator artery and the 

 epigastric explains the nature of the change which takes place when the origin 

 of the obturator artery is transferred from the one place to the other. In such 

 cases one of the anastomosing vessels may be supposed to have become enlarged, 

 and tlie posterior or proper root of the obturator artery to have remained unde- 

 veloped or to have been obliterated in a proportionate degree. 



The internal pudic artery is a branch of considerable size (smaller 

 in the female than in the male), which is distributed to the external 

 generative organs. The following description of this artery has refer- 

 ence to its arrangement in the male; its distribution in the female will 

 be noticed separately. 



The pudic artery arises from the anterior division of the internal 

 iliac, sometimes by a trunk common to it and the sciatic artery. Pro- 

 ceeding downwards, it emerges from the pelvis along Avith the sciatic 

 artery, through the great sacro-sciatic foramen, and continuing in a 

 uniformly curved course, it re-enters the pelvis by the small sacro- 

 sciatic foramen, immediately below the ischial spine, and passes forw^ard 

 on the inner side of the tuber ischii, in the substance of the obturator 

 fascia. 



Distant at first from the lower margin of the ischial tuberosity an 

 inch or an inch and a half, it approaches the surface at the inner 

 margin of the pubic arch, and lies subjacent to the triangular ligament 

 or superficial layer of the sulipubic fascia. Finally, pierciug this fascia, 

 it divides below the subpubic arch into the dorsal artery of the penis 

 and the arteiy of the corpus cavernosum. 



In the first part of its course, whilst within the pelvis, the pudic 

 artery lies to the outer side of the rectum, and in front of the pyri- 

 Ibrmis muscle and the sacral nerves. Thence onwards it is accompanied 

 by the jmdic nerve and veiu. On the ischial spine it is covered by the 

 gluteus maximus muscle close to its origin, lii the obturator fascia it 



