The aberrant course of the cutaneous component of the ilioinguinal nerve.

The ilioinguinal nerve was dissected in 196 adult human cadavers. A normal pattern of distribution, consistent with modern textual descriptions, was defined in 60% of inguinal regions. In 35% of the inguinal regions a previously undescribed aberrant course for the cutaneous component of the ilioinguinal nerve was observed in which it is incorporated within the genitofemoral nerve, entered the inguinal canal at the deep inguinal ring, coursed within the cremasteric layer and emerged into the subcutaneous tissue at the superficial inguinal ring on the dorsal side of the spermatic cord or the round ligament of the uterus. The cutaneous component of the ilioinguinal nerve is most frequently found on the ventral surface of the spermatic cord or round ligament during inguinal hernia operations thus an unrecognized aberrant course of this nerve within the spermatic cord is particularly susceptible to accidental trauma.