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Medicine LibreTexts

26.5G: Perineum

  • Page ID
    8256
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    The perineum is the region between the genitals and the anus, including the perineal body and surrounding structures.

     

    LEARNING OBJECTIVES

     

    Describe the perineum and its functions

     

    KEY TAKEAWAYS

    Key Points

     

    • The perineum refers to both external and deep structures.
    • Perineal tears and episiotomy often occur in childbirth with first-time deliveries, but the risk of these injuries can be reduced by preparing the perineum through massage.
    • The perineum is an erogenous zone for both males and females.

     

    Key Terms

     

    • lower rabbus: The term for perineum often used in the UK.
    • perineum: The region of the body inferior to the pelvic diaphragm and between the legs. It is a diamond-shaped area on the inferior surface of the trunk which includes the anus and, in females, the vagina.
    • episiotomy: A surgical incision through the perineum made to enlarge the vagina and assist childbirth.
    • perineal body: A pyramid-shaped fibromuscular mass in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle.

    In human anatomy, the perineum is the surface region between the pubic symphysis and coccyx in both males and females, including the perineal body and surrounding structures. The boundaries vary in classification but generally include the genitals and anus. It is an erogenous zone for both males and females.

    Illustrated drawing of the muscles of the female perineum, including the clitoris, bulbocavernosus, ischiocavernosus, external sphincter, and gluteus maximus.

     

    Perineum Illustration: Illustrated drawing of the muscles of the female perineum.

    The term perineum may refer to only the superficial structures in this region or be used to include both superficial and deep structures. The term lower rabbus is used colloquially in the UK to describe this structure. Perineal tears and episiotomy often occur in childbirth with first-time deliveries, but the risk of these injuries can be reduced by preparing the perineum through massage.

    The perineum corresponds to the outlet of the pelvis. Its deep boundaries are:

    • The pubic arch and the arcuate ligament of the pubis
    • The tip of the coccyx
    • he inferior rami of the pubis and ischial tuberosity, and the sacrotuberous ligament

    The perineum includes two distinct regions separated by the pelvic diaphragm. Its structures include:

    • Superficial and deep perineal pouches
    • Ischioanal fossa, a fat-filled space at the lateral sides of the anal canal bounded laterally by obturator internus muscle, medially by pelvic diaphragm and the anal canal.
    • Anal canal
    • Pudendal canal, which contains internal pudendal artery and the pudendal nerve