Perineumin

Perineumin is not a standard scientific term; the common anatomical term is the perineum. The perineum is the region of the trunk between the pubic symphysis and the coccyx, extending laterally to the thighs. It forms the outlet of the pelvis and supports the pelvic floor, helping maintain continence and contribute to sexual function.

Anatomical division and boundaries

The perineum is traditionally divided by a line between the ischial tuberosities into two triangles: the anterior urogenital triangle and the posterior anal triangle. The perineal body, a central fibromuscular mass, serves as an attachment point for several perineal muscles and anchors the pelvic floor.

Contents by region

- Urogenital triangle: in both sexes, this area contains the external genitalia and openings of the urinary tract. In males, this includes the root of the penis and the scrotum; in females, the vulva with the vaginal opening and external urethral meatus.

- Anal triangle: contains the anal canal and surrounding structures, including the anal opening and supporting tissues.

Muscles and fascia

Perineal muscles are organized into two layers: the superficial perineal pouch (bulbospongiosus, ischiocavernosus, and superficial transverse perineal muscles) and the deep perineal pouch (external urethral sphincter and deep transverse perineal muscle). The perineal membrane (inferior fascia of the urogenital diaphragm) and other fasciae form part of the supportive framework of the region.

Nerve, blood supply, and lymphatics

The perineum receives arterial blood primarily from branches of the internal pudendal artery. Innervation is mainly via the pudendal nerve (S2–S4) and its perineal branches. Lymphatic drainage is directed chiefly to the superficial inguinal nodes.

Clinical relevance

The perineum is involved in childbirth-related injuries (episiotomy and obstetric tears), infections, and anorectal disorders. Variation exists in perineal body size and genital anatomy, influencing function and appearance.

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