Lateral umbilical fold

The lateral umbilical fold overlies the inferior epigastric artery (a branch of the external iliac artery) and its accompanying veins. Unlike the median and medial umbilical folds, the contents of the lateral umbilical fold remain functional after birth. It originates just medial to the deep inguinal ring to the arcuate line on the posterior surface of the anterior abdominal wall.
Clinical significance.
The lateral umbilical fold is an important reference site with regards to hernia classification. A direct hernia occurs medial to the lateral umbilical fold, whereas an indirect hernia originates lateral to the fold. This latter case is due to the placement of the opening of the deep inguinal ring in the space lateral to the lateral umbilical fold, which allows the passage of the ductus deferens, testicular artery, and other components of the spermatic cord in men, or the round ligament of the uterus in women.