'PUDIC ARTERY. 425 



commencement of the epigastric artery, and sometimes to the external iliac at its 

 termination. 



In 361 cases observed by R. Quain, the origin of the obturator artery varied as 

 follows. In the proportion of 2 cases out of 3, it arose from the internal iliac^'in 1 

 case out of 3^, from the epigastric : in a very small number of cases (about 1 in 72), 

 it arose by t\vo 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 epigastric 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. 



When 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 crural ring, the 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 side 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 that the obturator artery is liable to be wounded in 

 the operation for dividing the stricture in a femoral hernia. 



The anastomosis which normally exists between the obturator 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 the posterior 

 or proper root of the obturator artery to have remained undeveloped or to have been 

 obliterated in a proportionate degree. 



IV. PUDIC ARTERY. 



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

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

 rative organs. The following description of this artery has reference 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. Proceeding 

 downwards, it passes superficially or posteriorly close to the ischial spiue, thus 

 emerging from the pelvis along with the sciatic artery, through the great 

 sacro-sciatic foramen. Continuing iu a uniformly curved course, it re-enters 

 the pelvis by the small sacro-sciatic foramen, immediately below the ischial 

 spiue, and passes forward on the inner side of the tuber ischii, in the sub- 

 stance 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 of the inner margin of the 

 pubic arch, and lies subjacent to the triangular ligament or superficial layer 

 of the subpubic fascia. Finally, piercing this fascia, it divides below the 

 subpubic arch into the dorsal artery of the penis and the artery of the 

 corpus caver nosum. 



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 pyriformis muscle 

 and the sacral nerves. Thence onwards it is accompanied by the pudic 

 nerve and vein. On the ischial spine it is covered by the glutens maximus 

 muscle close to its origin. In the obturator fascia it lies externally to the 

 ischio-rectal fossa and internally to the obturator internus muscle, and 

 beneath the triangular ligament it is crossed by the deep transverse perineal 

 muscle. 



F F 



