The perineum is an anatomical region in the pelvis, located between the thighs, and represents the most inferior part of the pelvic outlet. It is separated from the pelvic cavity by the pelvic floor and contains structures that support the urogenital and gastrointestinal systems, playing an important role in functions such as micturition, defecation, sexual intercourse, and childbirth. The perineum is a diamond-shaped structure, and its anatomical borders are defined by its exact bony margins and surface anatomy. The perineum is the tiny patch of sensitive skin between the genitals (vaginal opening or scrotum) and anus, and it’s also the bottom region of the pelvic cavity. The perineum may refer to just the part of the body that can be seen (the skin in between the genitals and the anus), or it may also refer to the underlying structures inside the body beneath the pelvic floor.

The perineal body is an irregular fibromuscular mass located at the junction of the urogenital and anal triangles in both males and females. In males, it is located between the anus and bulb of the penis, whereas in females, it is found between the anus and the posterior limit of the vulvar orifice. The perineal body helps strengthen the pelvic floor and contains skeletal muscle, smooth muscle, and collagenous and elastic fibers.

In common language, the perineum would be a persons bottom. This area contains a significant amount of adipose tissue with nerves, vessels, erectile tissue, and other structures. The perineum is an erogenous zone and is generally defined as the surface region between the pubic symphysis and the coccyx. 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.