Structure
The perineal membrane is a flat, triangular membrane that attach laterally to the inferior pubic rami. At its apex, it extends anteriorly towards the pubic symphysis and posteriorly it has a free border that spans the inferior pubic rami (Standring, 2016).
Anatomical Relations
The perineal membrane lies inferior to the levator ani muscle and covers much of the gap in the levator ani muscle, the urogenital hiatus.
Along its free posterior edge, it is continuous with the perineal body. The perineal body sits in the midline and consists of a collection of fibromuscular tissue. Anteriorly, the perineal membrane forms a thickening where it attaches to the arcuate ligament of the pubis. This thickening is called the transverse perineal ligament.
In the female, the urethra and the vagina pass through the perineal membrane, as well as some neurovascular structures that supply the external genitalia.
Function
The perineal membrane separates the superficial perineal pouch from the deep perineal pouch. It permits the passage of the urethra and vagina while helps to maintain their position during micturition, parturition, and defecation when the surrounding pelvic floor muscles are relaxed.
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.
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Perineal Membrane
The perineal membrane is a triangular fibrous layer that attaches the perineal body and vaginal side walls to the pubis.
