Cooper's posterior lamina of transversalis fascia.

The original description of the transversalis fascia and the internal inguinal ring by Astley Cooper in 1804 is recounted along with the immediate recognition of its importance by other surgical anatomists. The description he made in 1807 of two laminae has been essentially ignored or denied. The deep posterior lamina has been confused with a membranous condensation in the preperitoneal fascia. However, Lytle and Fowler reported a secondary or deeper internal ring and Mackay described the inferior epigastric artery perforating the transversalis fascia at its origin and then coursing cephalad on it to enter the rectus sheath anterior to the arcuate line. My experience with preperitoneal exposure of groin herniae, from the anterior and posterior approach, has demonstrated a posterior lamina deep to the epigastric vasculature attached to the pubic ramus. Repair of inguinal herniae should begin in the preperitoneal layer internal to Astley Cooper's bilaminar transversalis fascia and the epigastric vessels. This will ensure ligation of any peritoneal sac within the iliac fossae, as recommended by Bassini, or internal to the false neck, as described by Henry. This is the avascular, fissile, envelope in which Stoppa has so successfully placed prostheses.