Lexic.us

Definition of Musculus sphincter ani internus

1. Noun. An internal ring of smooth muscle formed by circular fibers of the rectum.

Medical Definition of Musculus sphincter ani internus

1. A smooth muscle ring, formed by an increase of the circular fibres of the rectum, situated at the upper end of the anal canal, internal to the outer voluntary external anal sphincter. This sphincter is maximally-contracted when the rectal ampulla is at rest -empty or relaxed to accommodate a distending faecal mass. It is inhibited with filling of the ampulla, increased distension and peristalsis. Synonym: musculus sphincter ani internus, internal sphincter muscle of anus. (05 Mar 2000)

Lexicographical Neighbors of Musculus Sphincter Ani Internus

Literary usage of Musculus sphincter ani internus

Below you will find example usage of this term as found in modern and/or classical literature:

1. Diseases of the intestines: A Text-book for Practitioners and Students of by Max Einhorn (1904)
"... more dense from above downward and increase to such a degree at the anal opening that they here form a thick ring (musculus sphincter ani internus). ..."

2. A Text-book of Histology and Microscopic Anatomy of the Human Body by Ladislaus Szymonowicz, John Bruce MacCallum (1902)
"... circular layer is thickened also, especially at the opening of the rectum, where it forms a strong circular band, the musculus sphincter ani internus. ..."

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