| orifice of internal acoustic meatus | The inner opening of the internal acoustic meatus on the posterior surface of the petrous part of the temporal bone. Synonym: porus acusticus internus, internal acoustic foramen, internal acoustic pore, auditory pore, internal auditory foramen, orifice of internal acoustic meatus. (05 Mar 2000) |
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| orifice of superior vena cava | The point of entry of the superior vena cava into the right atrium. Synonym: ostium venae cavae superioris, orifice of superior vena cava. (05 Mar 2000) |
| tricuspid orifice | An atrioventricular opening which leads from the right atrium into the right ventricle of the heart. Synonym: ostium atrioventriculare dextrum, ostium venosum cordis. (05 Mar 2000) |
| external urethral orifice | The slitlike opening of the urethra in the glans penis, the external orifice of the urethra (in the female) in the vestibule, usually upon a slight elevation, the papilla urethrae. Synonym: ostium urethrae externum, external opening of urethra, meatus urinarius, orificium urethrae externum. (05 Mar 2000) |
| ureteric orifice | The opening of the ureter in the bladder, situated one at each lateral angle of the trigone; wide gaping of the ostium usually indicates vesicoureteral reflux. Synonym: ostium ureteris, orificium ureteris, ureteral meatus, ureteral opening. (05 Mar 2000) |
| anal | <anatomy> Pertaining to the anus. (18 Nov 1997) |
| anal atresia | A congenital obstruction of the anal opening. Occurs in approximately 1 in 5,000 infants. This condition is corrected through surgery. (27 Sep 1997) |
| anal canal | The terminal portion of the alimentary canal; it extends from the pelvic diaphragm to the anal orifice. Synonym: canalis analis. (05 Mar 2000) |
| anal cleft | The sulcus between the buttocks (nates). Synonym: crena ani, anal cleft, crena clunium, gluteal cleft. (05 Mar 2000) |
| anal 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) |
| anal crypts | 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) |
| anal ducts | Short duct's lined with simple columnar to stratified columnar epithelium that extend from the valvulae anales to the sinus anales. (05 Mar 2000) |
| anal erotism | Pleasurable experience centreed around defecation and related activities associated with the anal zone, especially during the anal phase in one-to three-year-old children. (05 Mar 2000) |
| anal fascia | The fascia that covers the inferior aspect of the levator ani and coccygeus muscles. Synonym: fascia diaphragmatis pelvis inferior, anal fascia. (05 Mar 2000) |
| anal fissure | A tear or superficial laceration that can occur in the mucosa that lines the anal canal. (27 Sep 1997) |