The end of the alimentary tract through which faeces are expelled from the body. The orifice at the end of the anal canal is open only during defaecation; at other times it is kept closed by the muscles of the anal sphincter. (See also digestive system.)
The anus is the opening at the lower end of the bowel. It is kept closed by two muscles, the external and internal sphincters. The latter is a muscular ring which extends about 25 mm (1 inch) up the bowel, is nearly 6 mm (••• inch) thick, and is kept constantly contracted by the action of a nerve centre in the spinal cord. In disease of the spinal cord the muscle may be paralysed, resulting in inability to retain the motions or stools.
In nematodes, an opening of the alimentary system on the ventral side at the posterior end of the female nematodes.
n. the opening at the lower end of the alimentary canal, through which the faeces are discharged. It opens out from the *anal canal and is guarded by two sphincters. The anus is closed except during defecation. —anal adj.
(Indian) A pretty woman Anusry, Anusrey, Anusri, Anusrie, Anusrea, Anusreah, Anusrye... anusree
(proctatresia) partial or complete obstruction of the anus: a congenital malformation in which the anal canal fails to develop correctly and the rectum ends blindly above the muscles of the perineum. Many types exist, including developmental anal stenosis, persistent anal membrane, and covered anus (due to fused genital folds). Most mild cases of imperforate anus can be treated by a simple operation. If the defect is extensive a temporary opening is made in the colon (see colostomy), with later surgical reconstruction of the rectum and anus.... imperforate anus