Peritoneal cavity -greater sac extends from the diaphragm to the pelvic floor potential space between the parietal and visceral layer of peritoneum, With nothing but thin film of fluid Male,is a closed sac, Female,communicates with the exterior through the uterine tubes,the uterus,and the vagina. • Peritoneal cavity －greater sac • extends from the diaphragm to the pelvic floor potential space between the parietal and visceral layer of peritoneum, With nothing but thin film of fluid Male, is a closed sac, Female, communicates with the exterior through the uterine tubes, the uterus, and the vagina