title: Is inguinal hernia a defect in human evolution and would this insight improve concepts for methods of surgical repair?
abstract: In Homo sapiens sapiens and many mammalian quadrupeds, there is an absence of the posterior rectus sheath below the arcuate line (of Douglas) and an insubstantial transversalis fascia in the groin. This anatomical arrangement presents no particular functional anatomic difficulty for quadrupeds as their inguinal canal is directed "uphill" during ambulation and therefore is not subjected to significant gravitational stress. In humans, however, gravitational stress necessitated by erect posture, including bearing the weight of the intra-abdominal organs directed toward the lower abdomen, considerably amplifies this intrinsic anatomic weakness. It allows a significant number of pathologic inguinal hernias, both direct and indirect, to become clinically manifest and associated with a coincident increase in morbidity and mortality, especially in patients with strangulated hernias and/or delayed treatment. The morbidity is associated with a significant national economic loss secondary to work hour loss from pain, discomfort, surgical treatment, and rehabilitation following therapy. The mortality is usually associated with strangulation, especially in those in patients with delayed treatment. The lack of the evolutionary development of a strong posterior rectus sheath and transversalis fascia in the lower abdomen is thought to represent a significant specific anatomic defect in the evolution of humankind. If so, then perhaps methods for surgical repair will be directed toward correction of this defect and avoid, not encourage, such methods as the utilization of the weak or absent transversalis "fascia," which are doomed to a high recurrence rate, or other methods that are unnecessarily complicated, such as certain laparoscopic repairs of inguinal hernia.
authors.affiliation: Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, USA.
authors.forename: G
authors.initials: G
authors.lastname: McArdle
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002415:Cats; D004285:Dogs; D004724:Endoscopy / Q000379:methods; D006071:Gorilla gorilla; D006552:Hernia, Inguinal / Q000209:etiology* / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007264:Inguinal Canal / Q000002:abnormalities* / Q000254:growth & development; D002679:Pan troglodytes; D011817:Rabbits; D012589:Sciuridae; D012756:Sheep