Internal organs of man. Rectum
The rectum is the distal part of the large intestine. It is located in the posterior region of the small pelvis and ends in the crotch. The rectum has a length of fifteen to sixteen centimeters. Its upper border is located in accordance with the upper edge III of the sacral vertebra.
The organ has two bends: convex back( sacral) and convex forward( perineal).The border between the pelvic and crotch divisions passes in the area of attachment of the ascending anal muscle. The pelvic organ of the organ, located in the pelvic region, has an ampullar( having an expansion at the level of the sacrum in the form of an ampoule) and an unpubular department. The crotch department is considerably narrower. Passing through the perineum, it forms an anal canal opening with a posterior opening. The rectum has a gap in the shape of the slit, located transversely. The filled lumen has the shape of an oval.
In the upper part, the rectum has a three-sided peritoneum covering, which is gradually lost towards the bottom. In region IV, the vertebra of the sacral region, the peritoneum cover is preserved only on its anterior wall. The muscular membrane of the organ is represented in the form of two( inner circular and outer longitudinal) layers. The inner layer forms a thickening in the area of the anal canal - an involuntary( internal) anal sphincter. The outer layer has woven fibers of the anus of the anal muscle. An arbitrary( external) sphincter is a ring-shaped muscle, which consists of a subcutaneous and deep surface part.
The mucous membrane of the ampullar department forms two or three transverse, with a screw-like course of folds. In the anal canal, eight to ten anal posts( longitudinal folds) are formed, the base of which consists of smooth muscle and connective tissue. In the mucosa are the sebaceous glands and single lymphoid nodules. On the border of the skin and mucous are hair follicles and sweat glands. The sinuses of the sinuses( the recesses between the posts) are limited by the flaps that form the rectal-anal system. In this area, the venous plexus is located. Here, the single-layered cylindrical epithelium of the mucosa turns into a multilayered epithelium of a planar shape.
The mucosa has an increased absorption capacity, which causes a rectal route of administration of drugs and liquids.
Blood supply to the organ is provided by the upper, middle and lower rectal arteries. The outflow of venous blood is carried out on the same name veins. Outflow of lymph is carried out in the subordinal, upper rectal and internal iliac nodes.
The ampullary department serves as a reservoir and a tow truck. Through the anal canal, stool retention and control( arbitrary) are performed over the defecation process.
Ankokchikovym pain syndrome called functional disorders of the body, which are accompanied by pain in the sacrococcygeal, anal region. The reasons are pathological changes in the bones of the sacrococcygeal part caused by trauma, chronic spasm or inflammation of the pelvic floor muscles.
Proctalgia( neurological spasms) are accompanied by severe pain in the rectal area.
It is often observed anal itching. The causes of the manifestation of the initial anal itch are unknown. Secondary manifestation accompanies such diseases as hemorrhoids, fistulas and others.
The most common nonspecific diseases are paraproctitis and proctitis, hemorrhoids, prolapse of the bowel, anal fissure.
Constrictions of the body, as a rule, are acquired character and arise due to inflammation, trauma and external compression of the organ.
Among diseases of the rectum, there are observed the formation of benign, malignant tumors, non-epithelial and epithelial nature. The most common is a polyp( benign formation).
Malignant tumor( cancer) is diagnosed in 40% of all tumors.