| Perineum | |
|---|---|
| The muscles of the male perineum | |
| Gray's | subject #120 424 |
| Artery | perineal artery, dorsal artery of the penis, deep artery of the penis |
| Nerve | perineal nerve, posterior scrotal nerves, dorsal nerve of the penis, dorsal nerve of clitoris |
| Lymph | primarily superficial inguinal lymph nodes |
In human anatomy, the perineum (Late Latin, from Greek περίνεος - perineos[1]) is a region of the body including the perineal body and surrounding structures. There is some variability in how the boundaries are defined,[2] but the term generally includes the genitals and anus.
Contents |
It is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. The perineum is 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.[3] 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. The term lower rabbus is used colloquially in the UK to describe this structure. It is an erogenous zone for both males and females. 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, e.g. through massage.
The perineum corresponds to the outlet of the pelvis.
A wide variety of slang terms are commonly used for this area of the human body, most commonly "gooch," or "taint," or even "the spot where God sewed us up" but they generally refer to a smaller, less inclusive area -- just the surface skin region between the anus and the scrotum or vaginal opening.
The anogenital distance is a measure of the distance between the anus and the base of the penis or vagina. Studies show that the human perineum is twice as long in males as in females.[4] Measuring the anogenital distance in neonatal humans has been suggested as a noninvasive method to determine male feminisation and thereby predict neonatal and adult reproductive disorders.[5]
Its deep boundaries are as follows:[6]
A line drawn transversely across in front of the ischial tuberosities divides the space into two triangles:
| Name | Location | Contents |
| Urogenital triangle | the anterior triangle | in females, contains the vagina |
| Anal triangle | the posterior triangle | contains the anus |
The terminology of the perineal fascia can be confusing, and there is some controversy over the nomenclature. This stems from the fact that there are two parts to the fascia, the superficial and deep parts, and each of these can be subdivided into superficial and deep parts.
The layers and contents are as follows, from superficial to deep:
| superficial perineal pouch | Contains superficial perineal muscles: transversus perinei superficialis, bulbospongiosus, ischiocavernosus |
| inferior fascia of urogenital diaphragm, or perineal membrane | A membranous layer of the deep fascia. |
| deep perineal pouch | Contains the deep perineal muscles: transversus perinei profundus, sphincter urethrae membranaceae |
| superior fascia of the urogenital diaphragm | Considered hypothetical by some modern anatomists, but still commonly used to logically divide the contents of the region. |
The region of the perineum can be considered a distinct area from pelvic cavity, with the two regions separated by the pelvic diaphragm. The following areas are thus classified as parts of the perineal region:
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