312 EXTERNAL ILIAC ARTERY. 



The obturator artery may be very small or altogether wanting, its 

 place being supplied by a branch from the external iliac or epigas- 

 tric. 



EXTERNAL ILIAC ARTERY. 



The external iliac artery of each side passes obliquely downwards 

 along the inner border of the psoas muscle, from opposite the sacro- 

 iliac symphysis to the femoral arch, where it becomes the femoral 

 artery. 



Relations. It is in relation in front with the spermatic vessels, 

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

 fascia, which surrounds the artery and vein. At its commence- 

 ment 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 sepa- 

 rated 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 to Pou- 

 part's ligament ; and passing forwards between the peritoneum and 

 transversalis fascia, ascends obliquely to the border of the sheath of 

 the rectus. It enters the sheath near to its lower third, passes 

 upwards behind the rectus muscle, to which it is distributed, and 

 in the substance of that muscle it inosculates near the ensiform 

 cartilage with 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 inos- 

 culates with the obturator artery. 



The Epigastric artery forms a projection of the peritoneum which 

 divides 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 to the epigastric artery. It ascends obliquely 

 along Poupart's ligament, and curving around the crest of the ilium 

 between the attachments of the internal oblique and transversalis 



