The set of muscles and ligaments that form a base in the lower abdomen. This muscular complex separates the pelvic cavity from the perineal region and contains a large midline opening known as the urogenital hiatus. This hiatus allows the passage of the urethra in both men and women and the vagina in women. It is essential for supporting the pelvic organs and functions such as urinary and faecal continence and childbirth. It can also be known as the pelvic floor.