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 mural arch to the edge of the rectos, 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 he 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 earned 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 else 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 epigastrie: when the origin of the obturator from the iliac has become wanting, this branch takes its place and becomes the obturator.
2. The epigastric artery in passing the deep inguinal ring gives a branch, which goes out through the ring in company with the spermatic process, descends to the scrotum and is distri buted to the structures of the cord, to the tunica vaginalis, and to the cremaster, and anas tomoses with branches of the spermatic artery ; it is denominated by some the igferior sper matic artery.