The rectum is the distal colon. It is located in the posterior region of the pelvis and ends in the perineal region. The rectum is fifteen to sixteen centimeters long. Its upper border is located in accordance with the upper edge of the III sacral vertebra.
Rectum. Structure.
The body has two bends: a bulge back (sacral) and a bulge forward (crotch). The border between the pelvic and perineal sections passes in the area of attachment of the lifting anal muscle. The pelvic part of the organ, located in the pelvic region, has an ampullar (having at the sacral level extension in the form of an ampoule) and an nadampular part. The crotch department is much narrower. Passing through the perineum, it forms the anal canal opening with the posterior opening. The rectum has a lumen of the shape of a gap located transversely. The filled lumen has an oval shape.
In the upper part, the rectum has a trilateral peritoneal coating, which is gradually lost towards the bottom. In the region of the IV vertebra of the sacral region, the peritoneal cover is preserved only on its front wall. The muscular membrane of the organ is presented in the form of two (inner circular and outer longitudinal) layers. The inner layer is a thickening in the anal canal - an involuntary (internal) anal sphincter. The outer layer has an interweaving of fibers of the anal anus. An arbitrary (external) sphincter is a ring-shaped muscle, which consists of a subcutaneous and deep surface part.
The mucous membrane of the ampullar section forms two to three transverse, having a helical course of the folds. Eight to ten anal posts are formed in the anal canal (longitudinal folds), the base of which consists of smooth muscle and connective tissue. The sebaceous glands and single lymphoid nodules are located in the mucosa. On the border of the skin and mucous membrane are hair follicles and sweat glands. The anal sinuses (grooves between the pillars) are limited to the flaps that form the rectal-anal system. The venous plexus is located in this area. Here, the single-layer cylindrical epithelium of the mucous membrane passes into the stratified squamous epithelium .
The mucous membrane is characterized by increased suction capacity, which determines the rectal route of administration of drugs and fluids.
Blood supply to the organ is provided by the upper, middle and lower rectal arteries. The outflow of venous blood is made through the same veins. The outflow of lymph is carried out in the subaortic, superior rectal and internal iliac nodes.
The ampullar section serves as a reservoir and a tow truck. Through the anal canal, fecal retention and control (arbitrary) over the bowel movement is carried out.
Rectum. The disease.
Anokopchikovoy pain syndrome is called a functional disorder of the organ, which is accompanied by pain in the sacrococcygeal, anal section. As the reasons called pathological changes in the bones of the sacro-coccygeal region caused by trauma, chronic spasm or inflammation of the muscles of the pelvic floor.
Proctalgia (spasms of a neurological nature) are accompanied by severe pain in the rectal region.
Quite often, anal itching is observed. The causes of the initial anal itching are unknown. A secondary manifestation accompanies diseases such as hemorrhoids, fistulas, and others.
The most common non-specific diseases are paraproctitis and proctitis, hemorrhoids, prolapse of the intestine, anal fissure.
Constrictions of the organ, as a rule, are acquired in nature and arise due to inflammation, trauma and external compression of the organ.
Among the diseases of the rectum , the formation of benign, malignant tumors of non-epithelial and epithelial nature is observed. The most common is a polyp (benign formation).
A malignant tumor (cancer) is diagnosed in 40% of all tumors.