ABSTRACT
The pelvic cavity is superior to the muscular pelvic floor (or diaphragm), and the perineum is inferior to it. The sacrospinous ligament (1) gives origin to some of the pelvic floor muscles. The lesser sciatic foramen (2) lies inferior to the ligament, therefore inferior to the pelvic floor. Nerves and vessels passing through the lesser sciatic foramen enter the perineum, as do structures that pass through the pelvic floor.
