[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Pelvis](https://durgical.com/en/anatomy/region/pelvis/) › Perineal membrane [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Pelvis](https://durgical.com/en/anatomy/region/pelvis/) # Perineal membrane The perineal membrane is a tough sheet stretched across the front of the pelvic outlet; it supports the urethra and the erectile tissue of the vulva. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=pelvis&variant=male&select=perineal_membrane&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A tough triangular sheet stretched between the ischiopubic rami, pierced by the urethra. ## What it does Anchors the root of the penis (bulb and crura) from below; the urethra crosses it as the [membranous urethra](https://durgical.com/en/anatomy/intermediate-part-of-male-urethra/). ## Key points - Above it (deep pouch): the external urethral sphincter, compressor urethrae and deep transverse perineal. Below it (superficial pouch): clitoral crura, vestibular bulbs, Bartholin glands and their muscles - The old term «urogenital [diaphragm](https://durgical.com/en/anatomy/diaphragm/) » is outdated: the deep pouch is open above toward the [pelvis](https://durgical.com/en/anatomy/region/pelvis/), and the ischioanal fossa extends forward into it - In the female it is divided by the [vagina](https://durgical.com/en/anatomy/vagina/) into two halves and is weaker than in the male ## Key facts **Where** Triangular fibrous sheet across the anterior pelvic outlet, between the ischiopubic rami **Attaches** Ischiopubic rami laterally; perineal body posteriorly; pierced by the urethra and the vagina **Function** Separates the superficial and deep perineal spaces; attaches the vestibular bulbs and clitoral crura; supports the distal urethra and vagina ## Relations **Above** The deep perineal pouch with the [external urethral sphincter](https://durgical.com/en/anatomy/female-external-urethral-sphincter/), then the [levator ani](https://durgical.com/en/anatomy/levator-ani/) **Below** The superficial perineal pouch with the erectile tissue, its muscles and the [Bartholin glands](https://durgical.com/en/anatomy/greater-vestibular-gland/) **Lateral** The ischiopubic rami, to which it is attached **Behind** Its free back edge, fixed to the [perineal body](https://durgical.com/en/anatomy/perineal-body/), where the transverse perineal muscles lie **In front** A thickened front edge (transverse perineal ligament) leaving a gap below the [pubic symphysis](https://durgical.com/en/anatomy/pubic-symphysis/) for the deep dorsal vein of the [clitoris](https://durgical.com/en/anatomy/clitoris/) ## How to find it In dissection it appears once the superficial pouch is cleared: a tough triangular sheet across the front of the pelvic outlet, attached to both ischiopubic rami, with the perineal body at the middle of its back edge. ## On imaging Its position decides how a male urethral injury is classed: a retrograde urethrogram shows contrast leaking below it (bulbar urethra) or above it (membranous and [prostatic urethra](https://durgical.com/en/anatomy/prostatic-urethra-seminal-colliculus/)). Pelvic floor MRI can show it as a thin low-signal sheet. ## Common problems - Straddle injuries (falling astride a bar or a beam) can bruise the perineum and tear the urethra. - Perineal pain or numbness, for example from long cycling. ## How it is diagnosed Examination; ultrasound or MRI when needed. ## Treatment - Depends on the cause: rest, a better bicycle seat, or treatment of a urethral injury by a urologist. ## Clinical notes - Male: a straddle injury tears the bulbar urethra below the membrane; urine then fills the superficial pouch and spreads to the [scrotum](https://durgical.com/en/anatomy/scrotum/), penis and lower abdominal wall, not the thighs - Male: a pelvic fracture tears the urethra above the membrane; urine then leaks into the pelvis around the bladder and [prostate](https://durgical.com/en/anatomy/prostate/) - Female: with the perineal body and levator ani it forms the lowest level of vaginal support (DeLancey level III), holding the distal vagina and urethra in place ## Related conditions - [Stress urinary incontinence](https://durgical.com/en/conditions/stress-urinary-incontinence/) ## Test yourself Think of the answer, then tap the question to see it. ## Which structures lie above and which below the perineal membrane in the female? Above (deep pouch): external urethral sphincter, compressor urethrae, deep transverse perineal. Below (superficial pouch): clitoral crura, vestibular bulbs, Bartholin glands, their muscles. ## In a male straddle injury, where is the urethra torn and where does urine spread? The bulbar urethra below the perineal membrane; urine fills the superficial pouch and spreads to the scrotum, penis and lower abdominal wall, not the thighs. ## In a male pelvic fracture, where is the urethra torn relative to the perineal membrane? Above the perineal membrane; urine leaks into the pelvis around the bladder and prostate. ## Which level of vaginal support does the perineal membrane form? DeLancey level III, with the perineal body and levator ani, holding the distal vagina and urethra. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/perineal-membrane/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** membrana perinei TA2 2444 **Official Spanish (DeCS)** Membrana perineal **English (TA2)** Perineal membrane **Also called** fascia inferior diaphragmatis urogenitalis · fascia externa diaphragmatis urogenitalis ## Related - [Membranous urethra](https://durgical.com/en/anatomy/intermediate-part-of-male-urethra/) - [Bulbospongiosus](https://durgical.com/en/anatomy/bulbospongiosus-muscle/) Sources: Terminologia Anatomica (TA2); [Anatomy, Abdomen and Pelvis: Deep Perineal Space](https://www.ncbi.nlm.nih.gov/books/NBK538272/); [11.4 Axial Muscles of the Abdominal Wall, and Thorax](https://openstax.org/books/anatomy-and-physiology-2e/pages/11-4-axial-muscles-of-the-abdominal-wall-and-thorax) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/perineal-membrane/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/perineal-membrane/