Abdominal wall hernias occur where structures that are normally located within the peritoneal cavity protrude through a defect in the abdominal wall muscles. The worldwide lifetime incidence of abdominal wall hernias is approximately 5%, with 80% of hernias occurring in the inguinal canal and 5% in the femoral canal. The remaining 15% include incisional, spigelian, umbilical, epigastric and other hernia types.1 Groin hernias are classified into two groups: those originating along the inguinal canal and those originating outside the inguinal canal. The former group include direct and indirect inguinal hernias and the latter, femoral and spigelian hernias. excerpt
Pierre Vassallo (Sun,) studied this question.