Structure[edit] The perineum is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. The perineum is below the pelvic diaphragm and between the legs. It is a diamond-shaped area that 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 structures.