A diamond-shaped area on the inferior surface of the trunk which 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.
The perineum corresponds to the outlet of the pelvis.
The anogenital distance is a measure of male feminisation measuring the distance between the anus and the base of the penis. Studies show that the perineum is twice as long in males as in females. Measuring the anogenital distance in neonatal humans has been suggested as a noninvasive method to predict neonatal and adult reproductive disorders.
In Alfred Kinsey's 1967 report, he concluded that the perineum was one of the 6 key erogenous zones for males.
|Urogenital triangle||the anterior triangle||in females, contains the vagina|
|Anal triangle||the posterior triangle||contains the anus|
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.|