anal fistula

fistula /fis·tu·la/ (fis´tu-lah) pl. fistulas, fis´tulae   [L.] an abnormal passage between two internal organs or from an internal organ to the body surface.

Various types of fistulae, designated according to site or to the organs with which they communicate. (A), Genitourinary fistulae; (B), anal fistulae.

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anal fistula  one from the anus to the skin, sometimes communicating with the rectum.

arteriovenous fistula 

1. one between an artery and a vein.

2. a surgically created arteriovenous connection that provides a site of access for hemodialysis tubing.

blind fistula  one open at one end only, opening on the skin (external blind f.) or on an internal mucous surface (internal blind f.) .

branchial fistula  a persistent pharyngeal groove (branchial cleft).

cerebrospinal fluid fistula  one between the subarachnoid space and a body cavity, with leakage of cerebrospinal fluid, usually as otorrhea or rhinorrhea.

colonic fistula  one connecting the colon with the body surface or another organ.

craniosinus fistula  one between the cerebral space and one of the sinuses, permitting escape of cerebrospinal fluid into the nose.

enterovesical fistula  one connecting the urinary bladder with some part of the intestines.

fecal fistula  a colonic fistula that discharges feces on the body surface.

gastric fistula  one communicating with the stomach, either pathologically or surgically created through the abdominal wall.

genitourinary fistula  one between two organs of the urogenital system or between one of those organs and some other system.

incomplete fistula  blind f.

intestinal fistula  one communicating with the intestine; sometimes surgically created through the abdominal wall.

perilymph fistula  rupture of the round window with leakage of perilymph into the middle ear, causing sensorineural hearing loss.

pulmonary arteriovenous fistula  a congenital fistula between the pulmonary arterial and venous systems, so that unoxygenated blood enters the systemic circulation.

salivary fistula  one communicating with a salivary duct.

tracheoesophageal fistula  one connecting the trachea and esophagus, either pathologically or created surgically to restore speech after laryngectomy.

umbilical fistula  one communicating with the colon or the urachus at the umbilicus.

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anal fistula

n.

A fistula opening at or near the anus, usually into the rectum above the internal sphincter.

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anal fistula,

an abnormal opening on the cutaneous surface near the anus, usually resulting from a local abscess of the crypt and common in Crohn's disease. A perianal fistula may or may not communicate with the rectum. Also called fistula-in-ano.

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anal

relating to the anus.

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anal abscess

acute, purulent infections in the area of the anus, usually caused by gram-negative organisms. In dogs, these most often arise from the anal sacs.

anal atresia, atresia ani

congenital absence or stenosis of the anus manifested by an absence of feces and a gradual development of abdominal distention. Fistulae may develop between the rectum and urogenital tract. The anomalous development can occur in several forms and may be accompanied by similar atresia at higher levels of the intestine. There is usually normal development of sphincters. A dimple is usually evident at the point at which surgical intervention is required.

anal canal

the short, terminal, retroperitoneal segment of the intestinal tract between the rectum and anus.

anal constriction

a congenital constriction combined with vulvar constriction occurs in Jersey cattle.

anal fibroma

occurs in cattle and excision effected for esthetic reasons.

anal fistula

see perianal fistula.

anal fold

see anal fold.

anal furunculosis

see perianal fistula.

anal membrane

the dorsal part of the cloacal membrane in the embryo; when it eventually breaks down the dorsal passage becomes the rectoanal passage.

anal-perineal laceration

see rectovaginal fistula.

anal prolapse

the protrusion of a small amount of mucosa through the anus.

anal reflex

the pursing of the anal orifice when the perineum is stimulated; indicative of an animal with intact sacral segments of the spinal cord.

anal sac

see anal sacs.

Anal sacs in the dog. By permission from McCurnin D, Poffenbarger EM, Small Animal Physical Diagnosis and Clinical Procedures, Saunders, 1991

anal sacculitis

inflammation of the anal sacs.

anal sphincter

the internal anal sphincter is formed from smooth muscle of the anal canal while the external anal sphincter, which is larger and of greater importance in fecal continence, consists of striated muscle.

anal sphincter hypertrophy

occurs in aged dogs and may give rise to difficult and painful defecation.

anal stenosis

scar formation after perianal fistulae, trauma, severe anal sac disease, or treatment for neoplasia may result in a reduced lumen and particularly a loss of the capacity to dilate with passage of feces. Straining, passage of ribbon-like feces and constipation result.

anal ulceration

inflammation and ulceration of the perianal skin which may be associated with anal sac disease. Seen most commonly in German shepherd dogs.