ILIAC ARTERIES. 



843 



brane from the posterior to the anterior wall of 

 the abdomen. Its course is tortuous ; it passes 

 forward and inward ; when its origin is low, or 

 very near to the arch, at once upward; but 

 when its origin is high, at first downward in 

 front of the external iliac vein, and then 

 changing its direction, when it has reached the 

 reflection of the peritoneum, it ascends inward 

 toward the outer margin of the rectus muscle, 

 in front of the membrane, between it and the 

 fascia transversahs ; it reaches the margin of 

 the muscle from one and a half to two inches 

 above the pubis, and then passing behind it 

 enters its sheath, and continues its course upon 

 the posterior surface of the muscle toward the 

 umbilicus, and terminates by dividing into 

 branches, which anastomose freely with de- 

 scending branches of the internal mammary 

 artery ; the main course of the vessel is there- 

 fore oblique upward and inward ; and it may 

 be defined by a line drawn from the junction of 

 the middle and inner third of the crural arch to 

 within half an inch upon either side of the 

 umbilicus. 



The artery, when its origin is high, is situate, 

 at its outset, behind the peritoneum, posterior 

 to the deep inguinal ring ; in the rest of its 

 course it is at first beneath and then before it, 

 in immediate contact with it from the crural 

 arch to the edge of the rectus, and enclosed in 

 the fascia propria, but in the remainder sepa- 

 rated from it by the back of the sheath of the 

 muscle ; it therefore forms in this case a curve 

 in which the reflection of the peritoneum is 

 contained, and through which the vas deferens 

 forms a similar curve, the aspect of the curves 

 being however different, the convexity in the 

 former directed downward, and in the latter 

 outward and somewhat upward the two cords 

 hooking round each other; in its ascent from 

 the crural arch it is contained in the posterior 

 wall of the inguinal canal, between the fascia 

 transversalis and the peritoneum, crossing the 

 canal nearly at right angles, and intermediate 

 to the two rings, being distant from the outer 

 part of the superficial one, according to the 

 size of the aperture, from half an inch to an 

 inch and a half, and in its relation to the deep 

 ring varying from the margin of the aperture 

 itself to four or five lines distance from it. It 

 is accompanied sometimes by one, at others by 

 two veins; in the former case the artery is 

 always external and next to the margin of the 

 ring ; in the latter, one of the veins is at times 

 between it and the aperture. 



The relation of the artery to the inguinal 

 rings indicates at once that which it must hold 

 to the neck of the sac in the two original forms 

 of inguinal hernia ; in the oblique or external 

 inguinal hernia it is, as a matter of course, placed 

 beneath and on the inside; and in the direct or 

 internal inguinal, upon the outside of the 

 neck ; but in the former it must, in consequence 

 of its natural vicinity to the ring, and the dila- 

 tation of the latter, be close to and surround 

 the neck upon the two sides mentioned, while 

 in the second, unless the aperture be much 

 enlarged, it will be at a greater or less distance 

 from it ; the risk of danger to the vessel from 



cutting to the side, at which it lies, in a stran- 

 gulation at the neck of the sac, must therefore 

 be much greater in the former than in the 

 latter. In the case of a hernia originally ob- 

 lique and become direct by long continuance, 

 the artery carried inward along with the deep 

 ring, from the displacement of which the 

 hernia assumes the character of the direct form, 

 the artery is of course situate still upon the 

 inside of the neck, which at the same time it 

 surrounds to a greater extent than in the former 

 instances ; this third, though secondary, form of 

 inguinal hernia presents another case, in which 

 the relation of the vessel to the neck of the 

 sac demands attention the more that the true 

 nature of the case being obscure and the 

 hernia originally and secondarily direct, being 

 thence liable to be confounded, it is most im- 

 portant that it should be borne in mind that 

 the artery may be to the one side or the other, 

 according as the hernia has been originally or 

 secondarily direct. The epigastric artery is 

 also situate, in its ascent, external to the deep 

 femoral ring ; its distance from it, in the natural 

 state, is about half an inch ; but when hernia 

 is present, and the neck at all large, the epi- 

 gastric vessels are close to its outer and anterior 

 side, the vein, however, being between the 

 artery and the ring ; when the obturator artery 

 arises from the epigastric, the propinquity of the 

 latter to the ring is increased. 



The branches of the epigastric artery are 

 numerous, and some of them important. Its 

 first branches are two given off between its 

 origin, and the deep inguinal ring, higher or 

 lower, according to the situation of the origin 

 of the epigastric itself; they arise, in some in- 

 stances separately, in others by a single origin, 

 and they run over to the posterior surface of 

 the pubis, the other to anastomose with the 

 obturator artery ; the former, the pubic branch, 

 runs inward above Gimbernat's ligament, 

 sometimes along its anterior, sometimes along 

 its posterior margin, to the back of the 

 pubis, and according to its course is liable 

 to be situate before or behind the neck 

 of a femoral hernia. The second, the obtu- 

 rator branch, runs backward, downward and 

 inward toward the superior aperture of the pelvis, 

 i.e. in the direction, which the obturator artery 

 when arising from the epigastric takes ; having 

 descended into the pelvis it joins the obturator 

 at a variable distance between the origin of 

 that vessel from the internal iliac and the sub- 

 pubic foramen; frequently it divides at the 

 brim of the pelvis into two, of which one 

 joins the obturator and the other runs backward 

 along the brim and anastomoses with the ilio- 

 lumbar artery. This branch holds precisely the 

 same relation to femoral hernia which the 

 obturator when arising from the epigastric does; 

 it is very variable in size, and it is upon its de- 

 velopment as compared with that of the origin 

 of the obturator from the internal iliac that 

 depends, whether the former shall seem a 

 branch of the latter, or of the epigastric ; when 

 the origin of the obturator from the iliac has 

 become wanting, this branch takes its place 

 and becomes the obturator. 



