Rectum


Also found in: Dictionary, Thesaurus, Acronyms, Encyclopedia, Wikipedia.

rectum

 [rek´tum]
the distal portion of the large intestine, beginning anterior to the third sacral vertebra as a continuation of the sigmoid and ending at the anal canal. The feces, the solid waste products of digestion, are formed in the large intestine and are gradually pushed down into the rectum by the muscular action of the intestine. Distention of the rectum by the accumulating feces sets up nerve impulses that indicate to the brain the need to empty the bowels. The rectum is 15 to 20 cm (6 to 8 inches) long, with the anal canal making up the last segment. The anus is kept closed (except during the evacuation process) by muscular rings called the anal sphincters.



In a rectal examination, the examiner palpates the rectum by inserting a gloved and lubricated finger into the rectum. The examination helps in determining whether there are masses in the rectum or pelvic region, and in determining the size and texture of the prostate in men. More extensive examination of the interior surface of the rectum may be done by proctoscopy.

rec·tum

, pl.

rec·tums

,

rec·ta

(rek'tŭm; -tŭmz, rek'tă), [TA] Avoid the colloquial and jargonistic use of this word as a synonym of anus.
The terminal portion of the digestive tube, extending from the rectosigmoid junction to the anal canal (perineal flexure).
[L. rectus, straight, pp. of rego, to make straight]

rectum

(rĕk′təm)
n. pl. rec·tums or rec·ta (-tə)
The terminal portion of the large intestine, extending from the sigmoid colon to the anal canal.

rec·tum

, pl. rectums, recta (rek'tŭm, -tŭmz, -tă) [TA]
The terminal portion of the digestive tube, extending from the rectosigmoid junction to the anal canal.
[L. rectus, straight, pp. of rego, to make straight]

rectum

(rĕk′tŭm) [L., straight]
Enlarge picture
RECTUM: Rectum seen during colonoscopy
The lower part of the large intestine, about 5 in (12.7 cm) long, between the sigmoid colon and the anal canal. Its smooth muscle layer is the effector for the defecation reflex, the reflex centers for which are in the second, third, and fourth sacral segments of the spinal cord. See: illustration;

rectum

The 12.5 cm long, very distensible terminal segment of the large intestine, situated immediately above the anal canal. In spite of its name (rectus is Latin for straight), the rectum is curved and follows the hollow of the SACRUM. Its lining is smooth and the whole of the inside is accessible to the examining finger (see RECTAL EXAMINATION). Movement of bowel contents into the rectum causes the desire to defaecate.

rectum

the terminal part of the intestine of an animal which opens into the ANUS or CLOACA.

Rectum

The lower section of the large intestine, a digestive system organ. After food has passed through the stomach and intestines and been digested, the leftover material, in the form of feces, enters the rectum, where it stays until defecation.
References in periodicals archive ?
Five cattle were used to sample the epithelial tissue and the whole tissue in rectum. After the biopsy sampling of rectal epithelial tissue by an endoscope, they were euthanized by an intravenous overdose injection of sodium pentobarbital (100 mg/kg of BW) to excise the rectum.
Abnormalities in the structure of the anus or rectum can result in incontinence.
The majority of cancers of the colon and rectum are adenocarcinomas (a cancerous tumor arising in a secretory gland), which develop in glandular cells lining the inside of the colon and rectum.
Not taking him seriously, the next day the mother overheard her boy telling his grandmother that the accused pushed her finger into his rectum.
'In colonoscopy,' he explained, 'we use a tube with a tiny camera to look at the whole colon and rectum. We don't only find tumors early, but the test can also prevent colorectal cancer by removing polyps.'
Their scans and observations revealed that the shower head did not cause any internal damage; this despite the shower head reaching six inches deep into the man's rectum. The patient got released after 48 hours in the hospital.
Adjuvant treatment paradigms for colon and rectal cancer differ significantly despite the fact that the colon and rectum are contiguous sections of the same organ.
"Our suspicion is that the eggs were deliberately shoved into Akmal's rectum. But we did not see it directly," a spokesman for the hospital reportedly said. 
Additionally, ProSpace could be used to spare the rectum in hundreds of thousands of patients who are undergoing prostate cancer radiotherapy every year.
Based on the finding of CT and colonoscopy, diffuse infiltrative carcinoma of the rectum was strongly suspected; however, neither regular biopsies nor boring biopsies detected cancer cells.
negative diagnosis for "eosinophilic enterocolitis" for each pathologist, assuming a threshold of 20 eosinophils per HPF in the ileum or rectum and 50 in the hepatic flexure.
Out of 18 patients, who presented with bleeding per rectum (P/R), 14 were still having bleeding P/R by the end of 2 weeks that improved to 6 by the end of 6 weeks.