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a·nus, gen. and pl.
ani(ā'nŭs, -nī), [TA]
The lower opening of the digestive tract. It is associated with the anal sphincter and lies in the cleft between the buttocks, through which fecal matter is extruded.
Synonym(s): anal orifice
Etymology: L, orificium, an opening
1 the external opening at the end of the anal canal.
2 the anus, surrounded by the anal sphincter muscle.
orifice(or'i-fis) [L. orificium, outlet]
The mouth, entrance, or outlet of any anatomical structure. orificial (-fi'shal), adjective
The opening between the atrium and the ventricle on each side of the heart.
The opening of the esophagus into the stomach.
external urethral orifice
The exterior opening of the urethra. In the male, it is located at the tip of the glans penis; in the female, it is located anterior and cephalad to the vaginal opening.
ileal orificeIleocecal valve.
internal urethral orifice
The opening from which the urethra makes its exit from the bladder.
The opening between the left atrium and the left ventricle.
The opening of the ureter into the bladder.