Perineal fascia

The superficial fascia of the perineum, the superior and inferior fascia of the pelvic diaphragm, and the superior and inferior fascia of the urogenital diaphragm are distinguished.

The superficial (subcutaneous) fascia of the perineum (fascia perinei superficialis) is weakly expressed and is a continuation of the general subcutaneous fascia covering the adjacent parts of the body. This fascia is adjacent from below (outside) to the superficial muscles of the urogenital diaphragm, merging with their own fascia. In front of men, the superficial fascia of the perineum continues into the superficial fascia of the penis. On the sides, it grows to the ischial tuberosities. In the posterior part of the perineum, under the superficial fascia of the perineum, there is the inferior fascia of the pelvic diaphragm (fascia diaphragmatis pelvis inferior). This fascia grows with the proper fascia of the gluteus maximus muscle and lines the ischiorectal fossa. In the fossa, the fascia covers the outer surface of the obturator muscle, reaches the apex of the ischiorectal fossa, and then passes to the outer surface of the muscle that lifts the anus. Passing onto the outer surface of the external anal sphincter, the inferior fascia of the pelvic diaphragm ends in the tissue surrounding the anus. Anteriorly, the fascia reaches the posterior edge of the urogenital diaphragm, where it joins with its inferior and superior fasciae. From above (from the side of the pelvic cavity), the muscle that lifts the anus is covered by the superior fascia of the pelvic diaphragm (fascia diaphragmatis pelvis superior). Thus, the muscle that lifts the anus, as well as the external anal sphincter, together with the inferior and superior fasciae of the pelvic diaphragm covering them, form a muscular-fascial plate - the pelvic diaphragm (diaphragma pelvis).

In the anterior part of the perineum, the inferior fascia of the urogenital diaphragm (fascia diaphragmatis urogenitalis inferior) is located between the superficial and deep muscles, covering from below (from the outside) the deep transverse muscle of the perineum, as well as the sphincter of the urethra. On top of these muscles lies the superior fascia of the urogenital diaphragm (fascia diaphragmatis urogenitalis superior). Between these fasciae are the bulbourethral (Cowper's) glands in men and the large vestibular glands (Bartholin's) in women. The superior and inferior fasciae of the urogenital diaphragm fuse with the periosteum of the lower branches of the ischial and pubic bones on the sides, and with each other under the pubic symphysis, resulting in the formation of the transverse ligament of the perineum (lig. transversum perinei). This ligament is located in front of the membranous part of the urethra and does not reach the arcuate pubic ligament. Due to this, a narrow gap remains between the two ligaments, through which the dorsal vein and arteries of the penis or clitoris pass.

The superior fascia of the pelvic diaphragm is the lower part of the pelvic fascia (fascia pelvis). In the pelvic cavity, between the organs located in it, there are bundles of connective tissue, connective tissue septa, called the visceral fascia of the pelvis. In front, between the pubic symphysis and the lower part of the urinary bladder, connective tissue bundles form paired pubovesical (puboprostatic) ligaments (ligg. pubovesicales, s.puboprostatices) in men. Between the urinary bladder and the rectum in men, connective tissue bundles form a frontally located plate - the rectovesical septum (septum rectovesicale). In women, between the rectum and the vagina, connective tissue bundles form a transversely lying recto-vaginal septum (septum rectovaginale).

The female perineum has some characteristic features. Thus, the urogenital diaphragm in women is wider, not only the urethra passes through it, but also the vagina. The muscles of this area are less pronounced than the same muscles in men. The paired superficial transverse muscle of the perineum is often absent. The deep transverse muscle of the perineum is also poorly developed. Both fascia (upper and lower) of the urogenital diaphragm in women, on the contrary, are stronger. The muscle bundles of the sphincter of the female urethra also cover the vagina, intertwining with its walls. The tendinous center of the perineum is located between the vagina and the anus, consists of intertwined tendon and elastic fibers.

Ischial-rectal (anal) fossa. In the perineal region, on the sides of the anus, there is a paired depression - the ischiorectalis fossa (fossa ischiorectalis, s.ischioanalis). It has a prismatic shape, is filled with fatty tissue, is wide open downwards and narrows upwards, contains vessels and nerves. On a section made in the frontal plane, it looks like a triangle, with its apex facing upwards, towards the pelvic cavity. The apex of the ischiorectalis fossa corresponds to the lower edge of the tendinous arch of the pelvic fascia (arcus tendineus fasciae pelvis). The lateral wall of the ischiorectalis fossa is formed by the internal obturator muscle covered with fascia and the inner surface of the ischial tuberosity. The medial wall of the fossa is limited by the outer surface of the muscle levating the anus and the external anal sphincter, covered by the inferior fascia of the pelvic diaphragm. The posterior wall of the ischiorectal fossa is formed by the posterior bundles of the muscle levating the anus and the coccygeal muscle. The anterior wall of the ischiorectal fossa is the transverse perineal muscles. The fatty tissue filling the cavity of the ischiorectal fossa functions as an elastic cushion.

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