The transversalis fascia is the layer of connective tissue lining the internal surface of the transversus abdominis muscle, forming part of the endoabdominal fascia. It is the most important fascial layer for hernia repair biomechanics, as it defines the preperitoneal space (between the fascia and the peritoneum) where prosthetic mesh is placed. The deep inguinal ring is an opening in the transversalis fascia.
Forms the deep investing layer of the anterior abdominal wall internal surface, contributes to the posterior wall of the inguinal canal, and provides the structural layer that is reinforced in hernia repairs.
The transversalis fascia is the critical layer in hernia repair anatomy. The Shouldice repair reinforces the transversalis fascia in multiple layers with non-absorbable sutures for direct inguinal hernia. Total extraperitoneal (TEP) laparoscopic hernia repair works in the preperitoneal space between the transversalis fascia and the peritoneum. The deep inguinal ring weakness in indirect hernias is a defect in the transversalis fascia through which the hernia sac enters the inguinal canal. Mesh in open inguinal hernia repair (Lichtenstein) or laparoscopic repair covers the entire transversalis fascia defect.
Acquired weakness of the transversalis fascia forming the posterior inguinal canal wall (Hesselbach triangle) allows direct inguinal hernia protrusion medial to the inferior epigastric vessels, managed by mesh reinforcement of the transversalis fascia defect using the Lichtenstein technique or laparoscopic preperitoneal mesh placement.
