Transversalis fascia

The transversalis fascia is a thin aponeurotic membrane which lies between the inner surface of the transversus abdominis muscle and the extraperitoneal fascia.

It forms part of the general layer of fascia lining the abdominal cavity, and is directly continuous with the iliac and pelvic fasciae.

In the inguinal region, the transversalis fascia is thick and dense in structure and is joined by fibers from the aponeurosis of the transversus abdominis. It becomes thin as it ascends to the diaphragm and blends with the fascia covering the under surface of this muscle.

The spermatic cord in the male and the round ligament of the uterus in the female pass through the transversalis fascia at a spot called the deep inguinal ring. This opening is not visible externally, since the transversalis fascia is prolonged on these structures as the internal spermatic fascia.