In human anatomy, the perineum's generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. The perineum's the region of the body inferior to the pelvic diaphragm and between the legs. It's a diamond-shaped area on the inferior surface of the trunk which includes the anus and, in females, the vagina. Its definition varies: it can refer to only the superficial structures in this region, or it can be used to include both superficial and deep stru… (More on Perineum)