| MCAO | middle cerebral artery occlusion |
|---|---|
| MCAS | middle cerebral artery syndrome |
| MCAT | medical college admission test; middle cerebral artery thrombosis |
| MHA | major histocompatibility antigen; May-Hegglin anomaly; Mental Health Association; methemalbumin; mic... |
| MMA | mastitis-metritis-agalactia [syndrome]; medical management analysis; medical materials account; meth... |
| rectal | <anatomy> Pertaining to the rectum, the distal portion of the large intestine. (18 Nov 1997) |
|---|---|
| rectal ampulla | A dilated portion of the rectum just above the anal canal. Synonym: ampulla recti, ampulla of rectum. (05 Mar 2000) |
| rectal anaesthesia | General anaesthesia produced by instillation into the rectum of a solution containing a central nervous system depressant. (05 Mar 2000) |
| rectal cancer | A malignant tumour arising from the inner wall of the large intestine. The third leading cause of cancer in males, fourth in females in the u.s. Risk factors include heredity (family history), colon polyps, and long-standing ulcerative colitis. most colorectal cancers develop from polyps. Colon polyp removal can prevent colorectal cancer. Colon polyps and early cancer can have no symptoms so regular screening is important. Diagnosis of colorectal cancer can be made by barium enema or by colonoscopy with biopsy confirmation of cancer. (12 Dec 1998) |
| rectal columns | A number of vertical ridges in the mucous membrane of the upper half of the anal canal formed as the caliber of the canal is sharply reduced from that of the rectal ampulla. Synonym: columnae anales, Morgagni's columns, rectal columns. (05 Mar 2000) |
| rectal fistula | Abnormal passage communicating with the rectum. (12 Dec 1998) |
| rectal folds | The three or four crescentic folds placed horizontally in the rectal mucous membrane; the superior rectal fold is situated near the beginning of the rectum on the left side; the middle rectal fold (Nelaton's fold) is most prominent and consistent and projects from the right side about 8 cm above the anus (approximately the level of the floor of the rectouterine or rectovesical pouch); the inferior rectal fold is on the left side about 5 cm above the anus. Synonym: plicae transversales recti, Houston's folds, Houston's valves, Kohlrausch's valves, plicae recti, rectal folds, rectal valves. (05 Mar 2000) |
| rectal plexuses | See: inferior rectal plexuses, middle rectal plexuses, superior rectal plexus. (05 Mar 2000) |
| rectal prolapse | Protrusion of the rectal mucous membrane through the anus. There are various degrees: incomplete with no displacement of the anal sphincter muscle; complete with displacement of the anal sphincter muscle; complete with no displacement of the anal sphincter muscle but with herniation of the bowel; and internal complete with rectosigmoid or upper rectum intussusception into the lower rectum. (12 Dec 1998) |
| rectal reflex | The entrance of faecal matter into the rectum from the sigmoid colon causes an impulse to defecate. (05 Mar 2000) |
| rectal shelf | A shelf palpable by rectal examination, due to metastatic tumour cells gravitating from an abdominal cancer and growing in the rectovesical or rectouterine pouch. Synonym: Blumer's shelf. (05 Mar 2000) |
| rectal sinuses | The grooves between the anal columns. Synonym: Morgagni's sinus. Pockets or crypts in the columnar zone of the anal canal between the anocutaneous line and the anorectal line; the sinuses give the mucosa a scalloped appearance. Synonym: sinus anales, anal crypts, Morgagni's crypts, rectal sinuses. (05 Mar 2000) |
| rectal valves | The three or four crescentic folds placed horizontally in the rectal mucous membrane; the superior rectal fold is situated near the beginning of the rectum on the left side; the middle rectal fold (Nelaton's fold) is most prominent and consistent and projects from the right side about 8 cm above the anus (approximately the level of the floor of the rectouterine or rectovesical pouch); the inferior rectal fold is on the left side about 5 cm above the anus. Synonym: plicae transversales recti, Houston's folds, Houston's valves, Kohlrausch's valves, plicae recti, rectal folds, rectal valves. (05 Mar 2000) |
| rectal valvotomy | Cutting through rectal folds that are too rigid or large. (05 Mar 2000) |
| rectal venous plexus | A venous plexus resting upon the posterior and lateral walls of the rectum; it drains into the superior rectal vein to the portal, the middle rectal to the internal iliac and the inferior rectal to the internal pudendal. Synonym: plexus venosus rectalis, haemorrhoidal plexus. (05 Mar 2000) |