Anatomy Atlas

Perineal pouches

Spatium superficiale perinei; Spatium profundum perinei
Also: Superficial perineal pouch · Deep perineal pouch · Urogenital diaphragm (older term)
Space / regionHigh-yielddraftGURepro

Two fascial compartments of the urogenital triangle, separated by the perineal membrane. Their fascial attachments determine where urine spreads after urethral injury and how Fournier gangrene tracks.

Core anatomy

Location

In the urogenital triangle of the perineum, between the ischiopubic rami.

Boundaries
superficial pouch — inferior
Membranous layer of the superficial perineal fascia (Colles fascia), continuous with the dartos fascia and Scarpa fascia of the abdominal wall
superficial pouch — superior
Perineal membrane
deep pouch — inferior
Perineal membrane
deep pouch — superior
Inferior fascia of the pelvic diaphragm (the deep pouch is now regarded as open superiorly toward the pelvis)
lateral
Ischiopubic rami (where Colles fascia and the perineal membrane attach)
posterior
Fusion of Colles fascia with the posterior border of the perineal membrane at the perineal body
Contents
  • Superficial pouch (male): root of the penis (bulb and crura), bulbospongiosus, ischiocavernosus, superficial transverse perineal muscles, the proximal spongy urethra, and branches of the internal pudendal vessels and pudendal nerve
  • Superficial pouch (female): clitoris (crura), bulbs of the vestibule, greater vestibular (Bartholin) glands, the same muscles (see vulva)
  • Deep pouch (male): the intermediate (membranous) urethra, the external urethral sphincter, deep transverse perineal muscle, bulbourethral (Cowper) glands, and the dorsal vessels and nerves of the penis
  • Deep pouch (female): the proximal urethra, the external urethral sphincter with compressor urethrae and urethrovaginal sphincter, and the dorsal vessels and nerves of the clitoris
Communications

The superficial pouch is open anteriorly to the space beneath the membranous (Scarpa) layer of the anterior abdominal wall and the dartos of the scrotum and penis. It is closed laterally (ischiopubic rami), posteriorly (perineal body) and at the thighs (Scarpa/Colles fascia fuses with the fascia lata just below the inguinal ligament).

Found in

Mentioned in

Generated automatically from links in other entries.

Perineum: urogenital and anal triangles (inferior view)Diamond-shaped perineum bounded by the pubic symphysis, ischiopubic rami, ischial tuberosities, sacrotuberous ligaments and coccyx. A line between the ischial tuberosities separates the anterior urogenital triangle (urethra and vagina) from the posterior anal triangle (anus and ischioanal fossae). The perineal body lies at the center. The pudendal canal runs in the lateral wall of each ischioanal fossa.Pubic symphysisIschiopubic ramusIschialtuberosityIschialtuberosityUrogenital triangle(perineal membrane,superficial & deep pouches)UrethraVagina (♀)Perineal bodyIschioanalfossaIschioanalfossaAnus + externalanal sphincterPudendal canal(pudendal n. +int. pudendal vessels)Inferior rectal n.Sacrotuberous lig.Anal triangleCoccyxAnterior ↑ (inferior view, lithotomy)Dashed line: between the ischial tuberosities

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Perineum: urogenital and anal triangles. Inferior view with the patient in lithotomy (anterior at the top). A line between the ischial tuberosities divides the urogenital triangle from the anal triangle; the pudendal canal runs in the lateral wall of each ischioanal fossa.
Original schematic, created for this atlas.
Coronal section through the bladder, prostate and urethra showing levator ani, the fascial layers of the urogenital region, bulbospongiosus, ischiocavernosus and the ischioanal fossae
Coronal section: the fascial layers of the urogenital region, with bulbospongiosus and ischiocavernosus in the superficial pouch.
Henry Vandyke Carter, Gray's Anatomy of the Human Body, 20th ed. (1918), Fig. 407. Source · Public domain (Public domain in the US: published before January 1, 1931 (per Wikimedia Commons))
Male perineum with the superficial structures removed showing the bulb, prostate, bulbourethral glands and the internal pudendal artery with its branches to the penis
Deep dissection of the male perineum: bulb, bulbourethral glands and internal pudendal artery.
Henry Vandyke Carter, Gray's Anatomy of the Human Body, 20th ed. (1918), Fig. 543. Source · Public domain (Public domain in the US: published before January 1, 1931 (per Wikimedia Commons))
Male perineum from below with the layers of superficial perineal fascia reflected, showing the inferior rectal vessels and nerve crossing the ischioanal fossa
Layers of the superficial perineal fascia reflected (male).
Henry Vandyke Carter, Gray's Anatomy of the Human Body, 20th ed. (1918), Fig. 405. Source · Public domain (Public domain in the US: published before January 1, 1931 (per Wikimedia Commons))

Clinical correlations

Extravasation of urine after bulbar urethral rupture PANCE

Mechanism / lesion

A straddle injury tears the spongy (bulbar) urethra and Buck fascia in the superficial pouch.

Classic presentation

Urine and blood spread into the scrotum, penis and anterior abdominal wall deep to Scarpa fascia, but not into the thighs (fusion with the fascia lata) or the anal triangle (fusion at the perineal body). Classic "butterfly" perineal bruising outlines Colles fascia.

Membranous urethral injury PANCE

Mechanism / lesion

Pelvic fracture shears the membranous urethra in the deep pouch.

Classic presentation

Extravasation into the deep pouch and the retropubic (extraperitoneal) space around the bladder, with blood at the meatus and inability to void. Retrograde urethrogram before catheterization.

Spread of Fournier gangrene

Mechanism / lesion

Necrotizing infection tracks along Colles, dartos and Scarpa fascia.

Classic presentation

It can spread rapidly from the perineum to the scrotum, penis and anterior abdominal wall; the testes are usually spared because they have their own blood supply. See perineum.

High-yield PANCE pearls

  • Bulbar (straddle) urethral injury → urine into scrotum, penis, abdominal wall — not thighs.
  • Membranous urethral injury (pelvic fracture) → deep pouch and retropubic space.
  • Colles fascia = perineal continuation of Scarpa fascia.
  • Bulbourethral glands are in the deep pouch; Bartholin glands in the superficial pouch.

Imaging anatomy

X-ray

Retrograde urethrogram localizes the urethral tear and the pattern of extravasation.

CT

CT shows perineal hematoma, fluid and gas along fascial planes.

MRI

MRI defines perineal anatomy for urethral stricture planning and after trauma.

Physical exam

Surface landmarks

The perineal membrane spans the pubic arch between the ischiopubic rami; the bulb of the penis lies in the midline beneath bulbospongiosus.

Palpation

Inspect for a butterfly-shaped perineal hematoma, scrotal and penile swelling and blood at the meatus; check the distribution of swelling (spared thighs point to the superficial pouch).

Self-quiz

Q1.

The external urethral sphincter and bulbourethral glands in a male are located in which compartment?

Show answer

B

The deep perineal pouch contains the membranous urethra, the external urethral sphincter and the bulbourethral (Cowper) glands. The root of the penis and its muscles are in the superficial pouch.

Q2.

Why does urine from a ruptured bulbar urethra not spread into the thighs?

Show answer

B

The membranous layer of superficial fascia (Scarpa in the abdomen, Colles in the perineum) fuses with the fascia lata just below the inguinal ligament, closing off the thigh; it also fuses with the perineal membrane posteriorly, closing off the anal triangle.

Q3.

In a woman, the greater vestibular (Bartholin) glands lie in which compartment?

Show answer

B

The superficial perineal pouch in women contains the crura of the clitoris, the bulbs of the vestibule, the greater vestibular (Bartholin) glands and the superficial perineal muscles. In men, the bulbourethral (Cowper) glands are in the deep pouch.

Q4.

Colles fascia of the perineum is continuous with which layer of the anterior abdominal wall?

Show answer

E

Colles fascia (the membranous layer of the superficial perineal fascia) forms the floor of the superficial pouch and is continuous with the dartos fascia and the membranous (Scarpa) layer of the abdominal wall. This is why urine from a bulbar urethral rupture, or Fournier gangrene, can spread up onto the abdominal wall.

Q5.

A pelvic fracture tears the membranous urethra. Where does the urine extravasate?

Show answer

D

The membranous urethra lies in the deep pouch, so a pelvic-fracture injury leaks into the deep pouch and the retropubic space around the bladder. Spread into the scrotum, penis and abdominal wall is typical of a bulbar (straddle) injury in the superficial pouch. Obtain a retrograde urethrogram before catheterization.

Flashcards

See also