Anatomy

Omasum

The third stomach of ruminants, situated on the right side of the abdomen at a higher level than the fourth stomach and between this latter and the second stomach, with both of which it communicates. From its inner surface project large numbers of leaves or folia, each of which possesses roughened surfaces. In the center of each folium is a band of muscle fibers which produces a rasping movement of the leaf when it contracts. One leaf rubs against those on either side of it, and large particles of food material are ground down between the rough surfaces, preparatory to further digestion in the succeeding parts of the alimentary canal. (Black's Veterinary Dictionary, 17th ed)

National Library of MedicineMedical Subject Headings2026

Structured Summary

Abstract

The third stomach of ruminants, situated on the right side of the abdomen at a higher level than the fourth stomach and between this latter and the second stomach, with both of which it communicates. From its inner surface project large numbers of leaves or folia, each of which possesses roughened surfaces. In the center of each folium is a band of muscle fibers which produces a rasping movement of the leaf when it contracts. One leaf rubs against those on either side of it, and large particles of food material are ground down between the rough surfaces, preparatory to further digestion in the succeeding parts of the alimentary canal. (Black's Veterinary Dictionary, 17th ed)

MeSH Record

Classification

Broader headings

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MeSH Record

Synonyms

1 entry terms
  • Omasums

MeSH Record

Aspects Covered

24 allowable subheadings

Indexed with the subheadings abnormalities, anatomy & histology, blood supply, chemistry, cytology, diagnostic imaging, drug effects, embryology, enzymology, growth & development, immunology, injuries, innervation, metabolism, microbiology, parasitology, pathology, physiology, physiopathology, radiation effects, surgery, transplantation, ultrastructure, virology.

MeSH Record

Indexing Annotation

a ruminant's 3d stomach; dis: coord IM with STOMACH DISEASES /vet (IM); neopl: coord IM with STOMACH NEOPLASMS /vet + histol type /vet (IM); ulcer: coord IM with STOMACH ULCER /vet (IM)

MeSH Record

History Note

68

MeSH Record

Previous Indexing

  • Stomach (1966-1967)

MeSH Hierarchy

Tree Number

  1. A13.869.524w

AMA Style

References

  1. National Library of Medicine. Omasum. Medical Subject Headings (MeSH). 2026. Unique ID D009851. http://id.nlm.nih.gov/mesh/2026/D009851
  2. Omasum. In: Wikipedia. https://en.wikipedia.org/wiki/Omasum
  3. Omasum. In: Wikidata. https://www.wikidata.org/wiki/Q846746