SPHINCTER ANI
\sfˈɪŋktəɹ ˈanɪ], \sfˈɪŋktəɹ ˈanɪ], \s_f_ˈɪ_ŋ_k_t_ə_ɹ ˈa_n_ɪ]\
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By William R. Warner
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Many anatomists have described two sphincter muscles of the anus :-1. The S. exter’nus seu cuta’neus, Aspidiscos, Coccygio-cutane-sphincter, Orbicula'ris Recti, Constric'tor Ani, Coccygio-anal, (Ch.) It is situate around the anus; is elliptical from before to behind; flattened, and pierced at its middle. Its fibres describe concentric arcs, which are attached, behind, to the extremity of the coccyx, by a dense, areolar substance; and are confounded, anteriorly, with the bulbo-cavernosi and transversi perinasi muscles. This muscle contracts and closes the anus. 2. The inner or internal Sphincter Ani, Sphincter intestina'lis of Winslow, is by many anatomists considered as the termination of the circular fibres of the rectum. It is annular, and situate around the inferior extremity of the rectum, to the extent of about a finger’s breadth. It has the same uses as the other.
By Robley Dunglison
Word of the day
basidiomycota
- comprises fungi bearing the spores on basidium: Gasteromycetes (puffballs); Tiliomycetes (comprising orders Ustilaginales (smuts) and Uredinales (rusts)); Hymenomycetes (mushrooms; toadstools; agarics; bracket fungi); in some classification systems considered a division of kingdom comprises fungi bearing spores on a basidium; includes Gasteromycetes (puffballs) Tiliomycetes comprising the orders Ustilaginales (smuts) and Uredinales (rusts) Hymenomycetes (mushrooms, toadstools, agarics bracket fungi).