370 The External Iliac Artery 



THE EXTERNAL ILIAC ARTERY 



The external iliac artery continues the direction of the common 

 trunk, and extends from opposite the ala of the sacrum to the middle 

 of Poupart's ligament, where the name changes to common femoral ; 

 it is about 3^ in. long. (For surface-marking see p. 164.) 



Relations. Its most important relation is its vein, which lies to its 

 inner side, but which in the upper part of the artery is a good deal 

 posterior. The vas deferens, descending from the internal abdominal 

 ring towards the base of the bladder, is also an internal relation near 

 the pubes, and when the bladder is empty the pouch of peritoneum and 

 possibly some small intestine sink to the inner side. The beginning of 

 the rectum overlaps the artery of the left side (v. p. 353). 



Externally is the psoas in its sheath ; but, as the artery descends, 

 the psoas gets beneath it, and at the pubes the tendon is directly 

 posterior. The anterior crural nerve is a good way on the outer side of 

 the artery, being separated from it by the iliac fascia and the mass of 

 the psoas. 



Anteriorly are the bag of peritoneum with the intestines, and the 

 spermatic vessels sloping to the internal abdominal ring. The deep 

 circumflex vein coming from the iliac crest reaches the external iliac 

 vein by running over the front of the trunk near the pubes, and the 

 ureter may lie over the beginning of the artery ; so also does a branch 

 of the genito-crural nerve. 



Above, the artery rests upon the vein, and, lower down, upon the 

 psoas. The iliac fascia separates the artery from the psoas, and, de- 

 scending behind it, forms the posterior layer of the crural sheath, 

 the transversalis fascia descending on the front of the vessels. 



Branches, The deep epigastric is given offclose above Poupart "s 

 ligament, and, running upwards and inwards to enter the sheath of 

 the rectus, passes behind the inguinal canal. The internal abdominal 

 ring is to its outer side, and the external ring is, ot course, well to its 

 inner aspect, and much nearer to the skin. (See fig. on p. 306.) 



The course of the deep epigastric may be marked on tJic surface by 

 a line from the middle of Poupart's ligament, that is, from the end of 

 the external iliac artery, to the outer border of the rectus, about an 

 inch below the umbilicus ; and then straight up towards the ending of 

 the internal mammary (v. p. 1 56). 



At first the epigastric artery lies on the peritoneal side of the 

 transversalis fascia where it is going to form the crural sheath, 

 there being nothing behind it but the peritoneum. Thru, piercing the 

 transversalis fascia, it lies upon the back of the rectus, which there has 

 no sheath ; and a little higher it enters and ascemU within the sub- 

 stance of the rectus. Above the level of the umbilicus it anuMonx' 

 with the ending of the internal mammary ; earlier in its course it 



