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Perineal membrane | |
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![]() 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.) | |
Details | |
Location | Perineum |
Identifiers | |
Latin | membrana perinei |
TA98 | A09.5.03.002 |
TA2 | 2444 |
FMA | 30514 |
Anatomical terminology |
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.
It is the superior border of the superficial perineal pouch, and the inferior border of the deep perineal pouch.
The perineal membrane is triangular in shape. [1] It attaches to both ischiopubic rami of the pelvis. It also attaches to the perineal body. It is about 4 cm. in depth.[ citation needed ]
Its apex is directed forward, and is separated from the arcuate pubic ligament by an oval opening for the transmission of the deep dorsal vein of the penis or the deep dorsal vein of the clitoris.
Its lateral margins are attached on either side to the inferior rami of the pubis and ischium, above the crus penis.
Its base is directed toward the rectum, and connected to the central tendinous point of the perineum. The base is fused with both the pelvic fascia and Colle's fascia.
It is continuous with the deep layer of the superficial fascia behind the superficial transverse perineal muscle, and with the inferior layer of the diaphragmatic part of the pelvic fascia.
In males, 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. Its base is also perforated by the perineal vessels and nerves, while between its apex and the arcuate pubic ligament the deep dorsal vein of the penis passes upward into the pelvis.
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 perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis and the coccyx, including the perineal body and surrounding structures. There is some variability in how the boundaries are defined. The perineal raphe is visible and pronounced to varying degrees. The perineum is an erogenous zone.
The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis.
Articles related to anatomy include:
The bulbospongiosus muscle is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis. In females, it covers the vestibular bulb.
Older texts have asserted the existence of a urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of the urogenital diaphragm and superior fascia of the urogenital diaphragm.
The internal pudendal artery is one of the three pudendal arteries. It branches off the internal iliac artery, and provides blood to the external genitalia.
The external sphincter muscle of male urethra, also sphincter urethrae membranaceae, sphincter urethrae externus, surrounds the whole length of the membranous urethra, and is enclosed in the fascia of the urogenital diaphragm.
The membranous layer of the superficial fascia of the perineum is the deeper layer of the superficial perineal fascia. It is thin, aponeurotic in structure, and of considerable strength, serving to bind down the muscles of the root of the penis. Colles' fascia emerges from the perineal membrane, which divides the base of the penis from the prostate. Colles' fascia emerges from the inferior side of the perineal membrane and continues along the ventral (inferior) penis without covering the scrotum. It separates the skin and subcutaneous fat from the superficial perineal pouch.
The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet. Its lower boundary is the pelvic floor.
The dorsal nerve of the penis is the deepest division of the pudendal nerve; it accompanies the internal pudendal artery along the ramus of the ischium; it then runs forward along the margin of the inferior ramus of the pubis, between the superior and inferior layers of the fascia of the urogenital diaphragm.
The artery of bulb of penis is a short artery of large caliber which arises from the internal pudendal artery between the two layers of fascia of the urogenital diaphragm. It passes medialward, pierces the inferior fascia of the urogenital diaphragm and gives off branches which ramify in the bulb of the urethra and in the posterior part of the corpus spongiosum.
The superficial perineal pouch is a compartment of the perineum.
The deep perineal pouch is the anatomic space enclosed in part by the perineum, and located superior to the perineal membrane.
The urogenital triangle is the anterior part of the perineum. In female mammals, it contains the vagina and associated parts of the internal genitalia.
The membranous urethra or intermediate part of male urethra is the shortest, least dilatable, and, with the exception of the urinary meatus, the narrowest part of the urethra.
In human anatomy, the dorsal veins of the penis comprise the superficial dorsal vein of the penis and the deep dorsal vein of the penis.
The superior fascia of the urogenital diaphragm is continuous with the obturator fascia and stretches across the pubic arch.
The following outline is provided as an overview of and topical guide to human anatomy:
The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.
The vaginal support structures are those muscles, bones, ligaments, tendons, membranes and fascia, of the pelvic floor that maintain the position of the vagina within the pelvic cavity and allow the normal functioning of the vagina and other reproductive structures in the female. Defects or injuries to these support structures in the pelvic floor leads to pelvic organ prolapse. Anatomical and congenital variations of vaginal support structures can predispose a woman to further dysfunction and prolapse later in life. The urethra is part of the anterior wall of the vagina and damage to the support structures there can lead to incontinence and urinary retention.
This article incorporates text in the public domain from page 428 of the 20th edition of Gray's Anatomy (1918)