Diaphragm of the pelvis. Muscles of the pelvic diaphragm

The diaphragm of the pelvis, diaphragma pelvis, is formed by the right and left muscles lifting the anus, mm. Levatores ani dexter et sinister, right and left coccygeal muscles, mm. Coccygei dexter et sinister, anterior sphincter of the anus, m. Sphincter ani externus, and fasciae.

Muscles of the diaphragm of the pelvis.

1. The muscle lifting the anus, m. Levator ani, steam, triangular, consists of pubic-coccygeal and ilio-coccygeal muscles. Forms together with the fascia a funnel-shaped muscular plate, descending to the anus.

A) Lobkovo-coccygeal muscle , m. Pubococcygeus. The lateral part starts from the anterior part of the tendon arch of the muscle that raises the anus, arcus tendineus m. Levatoris ani. The tendon arch is a densified part of the occlusal fascia at the point where m begins. Levator ani and covering this muscle fascia.

The inner parts of the pubic-coccygeal muscle begin near the upper medial part of the occlusal opening from the inner surface of the branches of the pubic bone. Then the muscle is directed back, down and medially towards the coccyx, attached to the anal-coccyx ligament, lig. Anococcygeum, ventral sacrococcygeal ligament, lig. Sacrococcygeum ventrale, as well as to the anterior wall of the rectum, giving off a part of the bundles m. Sphincter ani externus. At the level of the crotch of the rectum, pubic-coccygeal muscles of the right and left sides are attached behind the gut, located under the rectum-coccygeal muscle, m. Rectococcygeus. Front m. Pubococcygeus is due to the urethra.

1) The muscle lifting the prostate gland , m. Levator prostatae, is a part of m in males. Pubococcygeus, intertwined in the capsule of the prostate gland. When cutting, pulls the iron up, thereby squeezing it.

In women these beams are called pubic-vaginal muscles, m. Pubovaginalis, they are weaved into the muscular membrane of the vagina .

2) Pubic-rectum muscle , m. Puborectalis, starts from the upper and lower branches of the pubic bone. Its internal fibers intertwine with the fibers of the muscle of the opposite side in front of the rectum and, circling the lateral surfaces of the prostate (in women of the vagina), are weaved into the longitudinal layer of the muscular shell of the rectum.

Function: m. Levator ani with all parts is mainly a compressor; The simultaneous contraction of the right and left pubic-coccygeal muscles facilitates the approach of the posterior wall of the rectum to the anterior one, which causes the narrowing of the distal rectum (the opening of the intestine takes the form of a transverse slit) - raising and pulling it upward and upward along with the bottom of the small pelvis; In women this muscle, in addition, narrows the vagina.

B) ileum-coccygeal muscle , m. Iliococcygeus, begins from the tendon arch, posteriorly from the beginning of the pubic-coccygeal muscle. Going back, down and medially, the muscle is attached to the coccygeal bone below the pubic-coccygeal muscle. Its internal bundles, together with the bundles of the same muscle of the opposite side, form a common tendon located between the rectum and the tip of the coccyx; Its outer beams are directed to the lateral edge of the coccyx. Behind the iliac-coccygeal muscle abuts the coccygeal muscle, covering it from above.

Function: raises the pelvic floor, makes it more elastic and stable.

2. Coccygeal muscle, m. Coccygeus, in the form of a triangular plate located on the inner surface of sacro-ovate
Ligaments. It begins with a narrow tip from the ischium awn, with a broad base attached to the lateral margins of the lower sacral and coccygeal vertebrae. The anterior edge of the muscle, adjacent to the posterior margin of the muscle that raises the anus, forms with it a solid muscle layer.

3. External sphincter of anus , m. Sphincter ani externus, covers the crotch (anal) region of the rectum, located distal to the pelvic diaphragm; Upper its bunches adjacent to the muscle that raises the anus. In the muscle, three parts are distinguished: the subcutaneous part, pars subcutanea, represented by thin muscle fibers attached to the skin of the anus; Superficial part, pars superficialis, consisting of fairly powerful circular fibers, and the deep part, pars profunda, formed also by large circular
Muscular bundles surrounding the anal canal.

The internal, more powerful part of the muscle is annular, and the outer part begins as a pointed rear end from the back surface and the tip of the coccyx, from the lig. Anococcygeum or in the skin. The muscle goes around the anal space of the rectum; In front, the outer part of the muscle ends with a pointed end in the tendon of the onion-spongy muscle and in the skin of the perineum.

A small part of the intestine smooth from the longitudinal bundles is attached to the striated muscle fibers.

Function: cutting, compressing the anus from the sides - the hole takes the form of a longitudinal slit.

Innervation: branches n. Pudendus: rr. Rectales inferiores, nn. Perineales, nn. Scrotales (labiales) anteriores and from plexus coccygeus nn. Anococcygei.

Blood supply: branches a. Pudenda interna: a. Rectalis inferior, aa. Perinealis, a. Dorsalis penis (clitoridis). Venous blood flows to the same veins in v. Iliaca interna. Lymphatic vessels divert lymph to nodi lymphatici inguinales superficiales.