EXTERNAL ILIAC bll 



\A{. The genital brancli of the itrcnito-crural nerve runs obliquely over its lower 

 third, and just before its termination it is crossed transversely by the deep circuni- 

 ilex iliac vein. The si)erniatic vessels lie for a short distance on the lower part of 

 the artery, and the vas deferens in the male and the ovarian vessels in the female 

 curve over it to descend to the pelvis. It is sometimes crossed at its origin by the 

 ureter. The external iliac lymphatic glands lie along the course of the artery. 

 The eonmiencement of its deep epigastric branch is also in front. 



Behind. — At first the artery lies partly upon it^ OAvn vein; lower doAvn upon 

 the inner border of the psoas; and just before it passes through the lacuna vascu- 

 losa, beneath Pou})art's ligament, uj^on the tendon of the psoas. The continuation 

 of the iliac into the pelvic fascia is also below it. 



To its inner side is the external iliac vein, the peritoneum, the descending 

 layer of fascia, and the vas deferens in the male, and ovarian vessels in the female. 



To its outer side is the psoas muscle and the iliac fascia. 



Variations. — (A) Tlic external iliac may be lunger or shorter than usual, according as the 

 coimuon iliac bifurcates above or below the usual spot. Wlien longer it often takes a very tor- 

 tuous course, making a partial loop or bend which may dip down below the brim of the pelvis. 

 (B) It may be much smaller in size than usual ; this is especially the case in those instances in 

 which the femoral or main vessel of the lower limb arises from the sciatic or other branch of the 

 internal ihac. It then often ends in the profunda. (C) It may give oiF a large branch, as the 

 deep circumflex iliac or deep epigastric, higher than usual. 



The collateral circulation is carried on (fig. 372), when the external iliac is tied, by the anas- 

 tomosis of the ilio-lumbar and lumbar arteries with the circumflex iliac ; the internal mammary 

 witli the dee)) epigastric ; the obturator with the internal circumflex ; the sciatic with the internal 

 circumflex and superior ])erforating ; the gluteal with the external circumflex ; the arteria comes 

 neryi isehiatici from tlie sciatic, with the perforating branches of tlie profunda ; tlie external 

 pudic with tlie internal jiudic ; tlie pubic branch of the obturator with the pubic branch of the 

 epigastric. 



The branches of the external iliac artery are: — (1) The deep epigastric; (2) 

 the deei) circumiiex iliac; and (3) several small and insignificant tw'igs to the 

 neighbouring psoas muscle and lymphatic glands. 



(1) The Deep Epigasteic Artery 



The deep epigastric artery usually comes oflp from the external iliac just 

 above Poupart's ligament. Immediately after its origin, the vas deferens in the 

 male, and the round ligament in the female, loop round it on their way to the 

 pelvis, drawing, as it were, the artery slightly inwards and downwards. It here 

 lies internal to the inner margin of the deep or internal alidominal ring behind the 

 inguinal canal, and a little to the upper and outer side of the femoral ring. Thence 

 it passes U])wards and inwards, above and to the outer side of the superficial or 

 external abdominal ring, lying between the fascia transversalis and the peritoneum 

 to the lower margin of the posterior layer of the sheath of the rectus (fold of Doug- 

 las). Having pierced the fascia transversalis at this point, it passes in front of 

 Douglas' fold and turns upwards between the rectus and its sheath, lying here 

 about midway betw^een the outer and inner edge of the muscle. Higher, it enters 

 the sul)stance of the muscle, and anastomoses with the superior epigastric, descend- 

 ing in the rectus from the internal mannnary. 



The situation of the artery between the two abdominal rings should be borne in 

 mind in the operation for strangulated inguinal hernia, and its near proximity to 

 the upper and outer side of the femoral ring should not be forgotten in the operation 

 for femoral hernia. The artery is accom])anie(l l)y two veins, of which the inner is 

 the larger. They end in a single trunk before opening into the external iliac 

 vein. 



The deep epigastric gives off the following small branches: — (a) The cremas- 

 teric, which runs with the vas through the inguinal canal, supplies the eremaster 

 muscle, and anastomoses Avith the spermatic, inferior external pudic, and sujierfieial 

 ]terinfeal arteries, (b) The pubic, which ])asses below, or sometimes above, the 

 femoral xmn to the l)ack of the pul)es, where it anastomoses with the pubic branch 



