The sac was opened on its anteromedial side to avoid injury to bowel. The sigmoid was densely adherent to the sac circumferentially. In the course of mobilization it was evident that part of the sac wall was made up of sigmoid (sliding hernia). The sac was freed at its junction with the sigmoid, leaving a defect in the posterior wall of the sac. The sigmoid was mobilized off cord structures deep into the internal ring.