322 EXTERNAL ILIAC ARTERY. 



peritoneum, and a thin layer of fascia, derived from the iliac fascia, -which 

 surrounds the artery and vein. At its commencement it is crossed by the 

 ureter, and near its termination by the crural branch of the genito-crural 

 nerve and the circumflexa ilii vein. Externally it lies against the psoas 

 muscle, from which it is separated by the iliac fascia ; and posteriorly it is 

 in relation with the external iliac vein, which, at the femoral arch, becomes 

 placed to its inner side. The artery is surrounded throughout the whole 

 of its course by lymphatic vessels and glands. 



Branches. Besides several small branches which supply the glands 

 surrounding the artery, the external iliac gives off two branches, the 



Epigastric, 

 Circumflexa ilii. 



The Epigastric artery arises from the external iliac near Poupart's liga- 

 ment; and passing forwards between the peritoneum and transversalis 

 fascia, ascends obliquely to the sheath of the rectus. It enters the sheath 

 near its lower third, and passes upwards behind the rectus muscle, to 

 which it is distributed, and in the substance of that muscle inosculates, 

 near the ensiform cartilage, w r ith the termination of the internal mammary 

 artery. It lies internally to the internal abdominal ring and immediately 

 above the femoral ring, and is crossed near its origin by the vas deferens 

 in the male, and by the round ligament in the female. 



The only branches of the epigastric artery worthy of distinct notice are 

 the Cremasteric, which accompanies the spermatic cord and supplies the 

 cremaster muscle ; and the ramusculus which inosculates with the obtura- 

 tor artery. 



The epigastric artery forms a prominence of the peritoneum which di- 

 vides the iliac fossa into an internal and an external portion ; it is from 

 the former that direct inguinal hernia issues, and from the latter, oblique 

 inguinal hernia. 



The Circumflexa ilii arises from the outer side of the external iliac, 

 nearly opposite the epigastric artery. It ascends obliquely along Foil- 

 part's ligament, and curving around the crest of the ilium between the 

 attachments of the internal oblique and transversalis muscle, inosculates 

 with the ilio-lumbar and inferior lumbar artery. Opposite the anterior 

 superior spinous process of the ilium, it gives off a large ascending branch 

 which passes upwards between the internal oblique and transversalis, and 

 divides into numerous branches which supply the abdominal muscles, and 

 inosculate with the inferior intercostal and with the lumbar arteries. 



Varieties in the branches of the external iliac. The epigastric artery not 

 unfrequently* gives off the obturator, which descends in contact with the 

 external iliac vein, to the obturator foramen. In this situation the artery 

 would lie to the outer side of the femoral ring, and would not be endan- 

 gered in the operation for dividing the stricture of femoral hernia. But 

 occasionally the obturator passes along the free margin of Gimbernat's 

 ligament in its course to the obturator foramen, and would completely en- 

 circle the neck of the hernial sac, a position in which it could scarcely 



* The proportion in which high division of the obturator artery from the epigastric 

 occurs, is stated to be one in three. In two hundred and fifty subjects examined by 

 Cloquet with a view to ascertain how frequently the high division took place, he found 

 the obturator arising from the epigastric on both sides one hundred and fifty times ; on 

 one side twenty-eight times, and six times it arose from the femoral artery. 



