Coronal section of anterior part of pelvis, through the pubic arch. Seen from in front. (Inferior layer labeled at bottom left.)
Median sagittal section of pelvis, showing arrangement of fasciæ. (Inferior layer labeled at center left.)
The perineal membrane is an anatomical term for a fibrous membrane in the perineum. The term "inferior fascia of urogenital diaphragm", used in older texts, is considered equivalent to the perineal membrane.
Shape and boundaries
It is triangular in shape, and about 4 cm. in depth.
It is perforated, about 2.5 cm. below the pubic symphysis, by the urethra, the aperture for which is circular and about 6 mm. in diameter, by the arteries to the bulb, and the ducts of the bulbourethral glands close to the urethral orifice; by the deep arteries of the penis, one on either side close to the pubic arch, and about halfway along the attached margin of the fascia; by the dorsal arteries and nerves of the penis near the apex of the fascia.
If the inferior fascia of the urogenital diaphragm is detached on either side, the following structures will be seen between it and the superior fascia:
- the deep dorsal vein of the penis
- the membranous portion of the urethra
- the deep transverse perineal muscle and the urethral sphincter muscles
- the bulbourethral glands and their ducts
- the pudendal arteries and dorsal nerves of the penis
- the arteries and nerves of the urethral bulb
- a plexus of veins