From Big Medical Encyclopedia

ANUS [canalis analis (PNA), anus; synonym: anal channel, proctal channel] — the distal piece of a rectum which is coming to an end with an anal orifice.


Length 3. the item fluctuates from 1,5 to 5 cm, it averages 3 cm of Kperedi from the proctal channel at men the cavernous bulb is located urethra (see), women have a lower part of a back wall of a vagina.

Fig. 1. The diagrammatic representation of a wall of an anus (in a section): 1 — the muscle lifting an anus; 2 — an outside sphincter of an anus; 3 — an internal sphincter of an anus; 4 — the crested line; 5 — anal bosoms; 6 — anal columns.

2 — 2,2 cm above an anus on a mucous membrane of the anal channel there are from 14 to 6 vertical parallel eminences — anal (proctal) columns of Morganyi (columnae anales). The fillet between each two columns from below will be closed a fold — the anal (proctal) gate (valvula analis) forming a blind pocket. These fillets and pockets (fig. 1) in total form anal (proctal) bosoms — crypts (sinus anales) from 0,2 to 0,8 cm in depth. At the basis of proctal columns are triangular shape of protrusion of a mucous membrane — proctal nipples — papillas. Well noticeable, a little acting zigzag line from proctal gates (folds) carries the name of the anorectal, gear or crested line (linea pectinata) and is border between a ferruterous epithelium of an ampoule of a rectum and the multilayer flat, deprived of hair and sweat glands epithelium of the proctal channel. At edge of an anus the multilayer epithelium gradually passes into epidermis of skin. The crested line is that place where in the course of an embryogenesis there was a connection of ectodermal skin protrusion with an entodermalny back gut, and proctal folds represent the remains of the germinal membrane existing between them.

Muscular coat 3. the item consists from internal (m. sphincter ani int.) and outside (t. sphincter ani ext.) sphincters 3. item. The internal sphincter represents a distal reinforced part of an inner circular muscular layer of a rectum (see. Rectum ). The outside sphincter which unlike internal is any consists of three portions — hypodermic, superficial and deep. Pass through all three portions of an outside sphincter from top to down and are attached to skin of fiber of the muscle lifting 3. the item (m. levator ani), consisting of three muscles — iliococcygeal (m. iliococcygeus), pubic and coccygeal (m. pubococcygeus) and a forehead-kovo-pryamokishechnoy (m. puborectalis). The m of levator ani strengthens a bottom of a small pelvis, holding the bodies located in it. At any reduction of a middle part of this muscle (m. pubococcygeus) 3. the item and the skin surrounding it are involved in depth and up. Normal tone of a sphincter 3. the item at men at measurement by spring sfinkterometry (see) it is on average equal to 600 g, its maximum force, i.e. strong-willed reduction, 900 g. At women, respectively, 520 and 775 g. Both sphincters, especially outside, play the main role in deduction a calla and intestinal gases. From a submucosa of the proctal channel in an anus posterior pyramids of smooth muscle fibers which are attached to the skin surrounding this opening — the muscle wrinkling skin 3 radially disperse. item (m. corrugator cutis ani). This muscle rolls inside a mucous membrane of the lower end of the proctal channel after the termination of the act of defecation (see. Defecation ).

Walls of the proctal channel are innervated by branches of a sexual nerve (n. pudendi) which accompany the lower pryamokishechny arteries.

Blood supply the proctal channel it is carried out by the lower pryamokishechny arteries (aa. rectales inf.), the being branches of internal sexual arteries (aa. pudendi int.). Branchings of the lower pryamokishechny arteries anastomose with branches of upper and average pryamokishechny arteries (aa. rectales sup. et med.).

Veins of the proctal channel form submucosal and hypodermic textures. The submucosal veniplex is located in the field of the lower ends of proctal columns in the form of a ring and represents accumulation of the cavernous veins forming small knots — cavernous little bodies (see. Hemorrhoids ). In the field of an outside sphincter the hypodermic texture is located. Outflow of blood is carried out on the lower pryamokishechny veins (vv. rectales inf.), passing together with the arteries of the same name. Branchings of the lower pryamokishechny veins anastomose with branches of average and upper pryamokishechny veins.

A lymph drainage from rich network limf, capillaries - skin 3. the item and limf, vessels of a mucous membrane of the proctal channel is carried out to limf, to nodes of inguinal area and to side sacral limf, to nodes.


Malformations enter into group of anorectal anomalies and in the existing classifications are considered among malformations of a rectum (see. Rectum ), since have with them a uniform embryogenesis and are often combined. However the isolated malformations 3 are observed. the item — an atresia, a stenosis, an ectopia. Unlike the most expressed malformations of a rectum forming on 4 — 6th week of embryonic development, they arise later — on 6 — 12th week.

Fig. 2. An atresia of an anus (it is specified by an arrow).

Atresia (lack of an anal orifice, the covered anus, atresia ani, anus imperphoratus) 8 — 10% of anorectal anomalies make. Arises owing to full preservation of a proctal membrane or an union of hypertrophied genital folds over a perforated membrane. In the latter case the proctal channel remains passable and can have more or less wide fistular course opening on the course of a perineal seam in any its place up to a bridle of a penis. Wedge, picture of an atresia 3. the item depends on anatomic option of anomaly. At a full atresia (without fistula — fig. 2) in 10 — 12 hours after the birth the child begins to make an effort strenuously, but meconium does not depart. At the same time symptoms of impassability of intestines arise and progress: abdominal distention, vomiting contents of a stomach, and then with impurity of meconium, Accrues toxicosis and eksikoz. In the started cases the disease is complicated by aspiration pneumonia, perforation of guts, peritonitis and the newborn perishes. In the presence of fistula the symptomatology is maleficiated and if fistula is rather wide — the phenomena of intestinal impassability are not observed and the child physically can normally develop.

Survey of a crotch at the time of the birth of the child is necessary for timely recognition of an atresia. Carry out the differential diagnosis in respect of specification of a «low» or «high» atresia.

At an atresia 3. operational treatment is shown to the item. The full atresia according to vital indications is korrigirut in an urgent order by method of a perineal proctoplasty (see. Rectum, operations ).

Fig. 4. The diagrammatic representation of some stages of an anoplasty at perineal fistula: 1 — the fluted probe is entered into a fistular opening; 2 — a section of fabrics on the probe; 3 — excision of the fistular course to a wall of a gut; 4 — crotch wound is taken in, the mucous membrane of a gut is hemmed to edge of a skin section, operation is complete.

In cases when there is a pellicle closing a gleam of a gut, rather crosswise section or its oval excision; need for mobilization of a gut and suture does not arise. In the presence of the fistula located close to the place of natural finding of an anal orifice in some cases at newborns happens to make enough careful expansion of a fistular opening a surgical clip and the otkhozhdeniye of meconium becomes satisfactory. If it does not work well, and also at children of more advanced age the anoplasty (fig. 4) is shown.

Results of surgical treatment quite satisfactory.

Stenosis (inborn narrowing 3. the item, stenosis ani) makes 5 — 8% of anorectal anomalies. The origins are similar to an atresia, but the proctal membrane remains not completely, and partially. Narrowing is localized most often in the field of the crested line of a proctal ring, considerably varying on degree of manifestation.

At a stenosis 3. the item a wedge, symptomatology in the period of a neonatality and the first months of life is absent more often since liquid the kcal freely passes through the narrowed opening, but at sharp degrees of a stenosis at the child from the first days of life locks are observed. Anyway with introduction of a feeding up locks become more and more persistent, defecation is followed by a strong natuzhivaniye and shout. Kal departs in the form of a tape or the narrow cylinder. Further progressively the volume of a stomach increases, fecal intoxication accrues hron.

The diagnosis is established at survey of a crotch and a manual rectal research. In some cases the stenosis needs to be differentiated with a disease of Girshsprunga (see. Megacolon ).

At a stenosis 3. items begin treatment with bougieurage, using Hegar's dilators or special buzha. Carry daily out 1 — 2 session, gradually increasing diameter of a buzh. Oiled liquid buzh enter through the narrowed opening and leave for 10 — 15 min. It is reasonable to combine bougieurage with a diathermy of proctal area or an electrophoresis with solution of novocaine, potassium iodide. Notable results are observed in 1 — 2 month of systematic treatment. The effect is better for those, than bougieurage is begun earlier.

In the cases which are not giving in to treatment by bougieurage operational treatment is shown. At the leaky and rather narrow narrowing ring are limited to a longitudinal section of the place of a stenosis with the subsequent mending of a wound in transverse direction. At sharp degree of a stenosis when there is a dense wide hem, intra sphincteric excision of the stenosing ring from a crotch with the subsequent podshivaniye of edge of a gut to edge of a skin section is most acceptable.

Results of treatment are quite satisfactory.

Ectopia (ectopia ani) is observed in 3 — 5% of cases of anorectal anomalies. Arises at insufficiency of an urorectal partition in the sagittal plane owing to what the crotch remains underdeveloped and there is no secondary migration of an anus on the usual place.

Fig. 3. A perineal ectopia of an anus at the girl.

Distinguish a perineal and vestibular ectopia. In the first case the anal orifice opens closer to a root of a scrotum at boys or back commissure of vulvar lips at girls (fig. 3) and at the same time the skin bridge between an opening and a sexual crack remains. In the second case at girls the skin bridge is absent and the mucous membrane of an entrance of the vagina passes into a mucous membrane of an anus.

Fig. 5. The diagrammatic representation of some stages of operation at a vestibular ectopia of an anus (according to Stone): 1 — the line of a section around a malrelated opening and on a crotch in the field of a normal arrangement of an anus (dashed lines); 2 — the gut mobilized for 3,5 — 4 cm is transferred for threads handles to a wound of a crotch through the tunnel which is previously done in perineal cellulose and muscles of a crotch; 3 — stitches are put, operation is complete.

At an ectopia functional disturbances are absent. Reduction of the outside sphincter surrounding an anus is well-marked, and the manual rectal research defines good passability of an anus and the expressed tone of the switching device. All listed signs are important distinguishing characters of an ectopia from fistular forms of an atresia of a rectum of which functional deviations and an extra sphincteric arrangement on a crotch of a fistular opening are characteristic. At a part of patients at an ectopia 3. the item of treatment is not required, napr, from boys, and also from girls with a perineal ectopia. At a vestibular ectopia it is necessary to korrigirovat anomaly in the surgical way because future woman is expected by considerable aberrations: cases of commission of sexual intercourse through a malrelated anal orifice are known; besides, direct proximity 3. the item and a sexual crack promotes infection of genital and urinary tract. Operation is carried out after 1 year of life of the child. It consists in movement of abnormally located anal orifice to the usual place (fig. 5). Functional results of surgical treatment are quite satisfactory.

Damages can be caused by the different reasons. The rupture of a sphincter and the proctal channel is rather often observed during a childbed. They easily are eliminated if immediately after the delivery to put stitches. Home and professional accidents 3. items can arise during the falling by a crotch on the acting or sharp objects: the stakes, pipes acting parts of tools and devices, etc. Injuries 3. items can arise also at breakdown of a clyster tip, the thermometer, etc. To damages 3. also masturbation can provide the item. Damages 3 are sometimes observed. the item the foreign bodys entered into the proctal canal in a state of intoxication or with a criminal intent (bottles, sticks, etc.).

The isolated gunshot wounds 3. items meet seldom (see. Rectum, damages ).

Among damages 3. the item should be distinguished: a) wounds of soft tissues with damage of a skin ring and a mucous membrane 3. the item without damage of a sphincter; b) wounds of area 3. the item with damage of a sphincter; c) separation of a rectum.

In the first case of a wound usually have the form of a trench with small defect of skin and mucous membrane. Depth of a wound is insignificant, and it does not reach a sphincter.

Weight of damages of the second group depends on the volume of destructions. The open wound surface is constantly infected with fecal masses that leads to development of purulent complications.

The separation of a rectum is usually diagnosed without effort since at survey instead of a sphincter and a mucous membrane 3. the fatty tissue impregnated with blood and a stake is visible to the item.

All damages 3. items demand, as a rule, urgent surgical intervention — removal of a foreign body, processing of a wound, imposing of intestinal fistula, etc.; in later terms reconstructive operations are necessary.

Functional disturbances. Various organic and functional diseases and damages of area 3. and. can result in insufficiency of its closing function. This insufficiency is divided into three degrees: defective delay of gases (I degree), involuntary allocation of liquid excrements or not deduction of klizmenny water (II degree), incontience firm calla (III degree). At insufficiency of the I degree the good effect allows to lay down. gymnastics of a sphincter, general hardening of an organism, prevention of ponos.

At the expressed forms of insufficiency of function 3. items (II and III stetep) apply a sphincteroplasty. Most often apply sewing up of a sphincter 3. the item according to Lockhart — Mammeri (rifny seams on a back semi-circle of a press), a resection rubtsovo the changed sphincter with sewing up of its ends, and also, according to individual indications, plastic surgeries — formation of an artificial press from a thin muscle of a hip (Fayerman's method) or from big gluteuses, to plastic with use of a fascial tape from an aponeurosis of a hip (Vreden's method). At the expressed deformations 3. items with sharp disturbance of its function make plastic surgeries after temporary assignment a calla by imposing of a preliminary kolostoma.

Diseases. To the most frequent acquired diseases 3. items, belong hemorrhoids, a cryptitis, a papillitis, a sphincteritis (an anusitis, annite), a crack 3. item and paraproctitis.

Hemorrhoids — the widespread disease, to-rogo is the cornerstone a hyperplasia of cavernous veins and little bodies of a submucosa of distal department of a rectum and 3. item; arises under the influence of various factors, demands conservative and in need of operational treatment (see. Hemorrhoids ).

Cryptitis— acute, subacute or hron, the inflammation of morganiyevy bosoms connected with injuries of bosoms and the output channels of proctal glands opening in them dense and acute inclusions of fecal masses with the subsequent infection. Complaints at a cryptitis come down to burning sensation and a foreign body in 3. to the item, tenesmus.

At a manual research morbidity and hypostasis of the inflamed anal bosom is defined, and at an anoskopiya its hyperemia. When inflammatory process took all bosoms, at a manual research consolidation is determined by the course of all crested line — «pectenosis». Treatment conservative (see. Proctitis, treatment ), at unsuccessful treatment excision of a bosom is shown. The cryptitis is often combined with a papillitis and accepts hron, the current which is characterized by a proctal itch, pains, a spasm of a sphincter 3. item. The abscess formed in an anal bosom can independently be opened in a gleam 3. the item that leads to formation of incomplete internal fistula, or outside, pro-butting a muscular wall of a rectum and getting into a pararectal fat; in the latter case the purulent paraproctitis develops (see. Paraproctitis ).

Papillitis — an inflammation, sometimes and the subsequent hypertrophy of proctal nipples because of their constant traumatization fecal masses, especially at locks, a proctal crack, hemorrhoids, a paraproctitis. It is necessary to distinguish hypertrophied proctal nipples from proctal fibrous polyps that works well most often only at gistol, a research of remote educations. Symptoms of a papillitis — a proctal itch, pains in the area 3, the item. At external examination and a manual research of a rectum the increased and painful nipples, maceration of perianal skin, sometimes an ulceration of a top of a nipple are defined. Treatment conservative (see. Proctitis, treatment ), at unsuccessful treatment operation — removal of a nipple is shown.

Sphincteritis — inflammation of skin and mucous membrane of the proctal channel. In the acute period — complaints to an itch, pains and burning sensation, false desires on defecation. Often accompanies an aggravation hemorrhoids (see), a proctal crack, it is combined, as a rule, with a cryptitis and a papillitis; sometimes has specific character (gonorrheal annite) or (is more often at children) parasitic (at defeat by pinworms). Treatment, as at a proctitis — a sparing diet, microclysters with fish oil, kolibakteriny, infusion of a camomile, colloid silver; inside entersseptol. Appoint also candles with a belladonna, irrigations of the proctal channel disinfecting solutions, ointments with antiseptic agents and streptomycin. At a specific sphincteritis etiotropic treatment, at parasitic — antivermicular.

Fig. 6. The anus stretched in transverse direction by a rectal speculum: on a back wall (in the direction of 6 hours of the conditional dial) defect of a mucous membrane of a rhomboid form after excision of a crack is visible.

Anal fissure is located in 90% of cases on a back (coccygeal) wall of the proctal channel. Symptoms — severe pains after defecation (of several minutes to 2 — 3 hours), small bleeding during a chair, a spasm of a sphincter 3. item. At survey on a wall of the proctal channel defect of a mucous membrane is defined triangular shape, an upper (proximal) part to-rogo almost always has a hypertrophied site («a sentry hillock»). The acute crack in most cases will respond to conservative treatment — a sparing diet, aperient means, oil microclysters, candles. Simple extension of a sphincter 3. the item across Rekamye, offered in 1828, is not applied in connection with injury and insufficient therapeutic effect. At hron, a crack good results are yielded by novocainic and alcohol blockade. More radical operation is excision of a crack within a healthy mucous membrane (fig. 6) and a spasmolysis of a sphincter by means of an injection of anesthetics of the prolonged action.

Fistulas of an anus most often arise because of an acute paraproctitis (see. Paraproctitis ) and it is very rare in connection with tuberculosis of intestines, an actinomycosis of a rectum. Main difference of banal fistulas 3. the item from specific consists that at banal fistulas the internal opening of fistula is located at the level of the crested line in one of anal bosoms. In relation to muscles of the proctal channel fistulas divide into simple — low level (intra sphincteric), chressfinkterny and difficult — a high level (extra sphincteric).

Diagnosis of fistulas 3. the item is based on external examination, a manual research, sounding, test with dyes (methylene blue) and fistulografiya.

Treatment surgical. At simple fistulas Gabriel's operation — excision of a front wall of fistula a triangular rag in a gleam of a rectum together with an internal opening of fistula is most effective. At a chressfinkterny arrangement of the fistular course the syringectomy in a gleam of a gut with sewing up of a bottom of a wound (without skin) catgut seams is shown. At high extra sphincteric fistulas excise the fistular course on a crotch and liquidate an internal opening of fistula or by means of a silk ligature, or plastics a skin and mucous rag, or by the difficult fistulas Operation dosed a sphincterotomy 3. items choose individually depending on the general condition of the patient, the previous interventions and function of a sphincter.

Itch of an anus idiopathic, suigenny arises out of communication with accompanying the general (diabetes) or proktol. (proctitis, hemorrhoids, etc.) diseases; amplifies at night and in heat, often deprives of patients of working capacity. Treatment consists in purpose of a sparing diet and microclysters with colloid silver (25 — 30 instillations on a course of treatment for the night, after a cleansing enema); inside Enteroseptolum on 0,5 g 2 — 3 times a day. Sanitation of skin, a careful toilet after defecation is obligatory. In persistent cases (only at dry forms of an itch) — intradermal obkalyvaniye of perianal area of 0,2% methylene blue in 0,5% solution of novocaine. At unsuccessful treatment operations — crossing of cutaneous nerves, etc. are possible (though are a little effective). Fortifying therapy and sometimes consultation of the psychiatrist is necessary.

Condylomas — warty growths 3. the items connected with irritation of perianal skin of a crotch at a proctosigmoiditis of a virus etiology. The current is long, it is necessary to exclude syphilis and gonorrhea. Treatment at first as at a proctal itch, and then removal of condylomas, is better by a cryolysis (see. Cryotherapy ).

Tumors — high-quality (polyp, fibroma, nevus) and malignant (adenocarcinoma, planocellular cancer, sarcoma, pigmental and pigment-free melanoma). The polyp and fibroma are subject to transproctal removal. At cancer and a melanoma complex treatment, as is shown at similar tumors of a rectum (see. Rectum, tumors ).

Bibliography: Aminev A. M. Guide to a proctology, t. 1 — 3, Kuibyshev, 1965 — 1973; Braytsev V. R. Diseases of a rectum, M., 1952;

Isakov Yu. F., Lyonyushkin A. I. and Doletsky of S. Ya. Hirurgiya of malformations of a large intestine at children, M., (to download) 1972;

Lyonyushkin A. I. Proctology of children's age, M., 1976, bibliogr.;

/ _ 2U3gdxFihSg7 Red A. N. The atlas of operations on direct and thick guts, M., 1968 (to download);

Yakovlev N. A. (To download) the atlas of proctologic diseases, M., 1976;

Duhamel J. Anal fistulae in childhood, Amer. J. Proctol., v. 26, p. 40, 1975, bibliogr.; G o 1 i g h e r J. C. Surgery of the anus, rectum and colon, L., 1975, bibliogr.; Mandache F. Die Chirurgie des Rektums, B., 1974; Stephens F. D. a. Smith E. D. Ano-rectal malformations in children, Chicago, 1971.

V. D. Fedorov; A. I. Lyonyushkin (it is put. hir.).