omasum

anatomy

Also known as: manyplies, psalterium

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Last updated

July 1, 2026

Quick Summary

The omasum is the third compartment of a ruminant's four-chambered stomach, which includes the rumen, reticulum, and abomasum. This specialized stomach structure is characteristic of animals like cows, sheep, and goats, enabling them to digest fibrous plant material.12

The omasum's primary function is to absorb water and other nutrients from the partially digested food before it moves to the abomasum, the final compartment often referred to as the "true stomach". Its inner lining features numerous folds of tissue, giving it a book-like appearance, which increases the surface area for absorption.1

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artiodactyl
Digestive system
… (or paunch), the reticulum, the omasum (psalterium or manyplies)—which are all believed to be derived from the esophagus—and the abomasum (or reed), which corresponds to the stomach of other mammals. The omasum is almost absent in chevrotains. Camels have a three-chambered stomach, lacking the separation of omasum and abomasum; the…
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… (or paunch), the reticulum, the omasum (psalterium or manyplies)—which are all believed to be derived from the esophagus—and the abomasum (or reed), which corresponds to the stomach of other mammals. The omasum is almost absent in chevrotains. Camels have a three-chambered stomach, lacking the separation of omasum and abomasum; the…
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ruminant
…of the stomach (the reticulum, omasum, and abomasum), where it is further digested with the aid of various essential microorganisms that live in the stomach. The pseudoruminant digestive process is very similar, also involving regurgitation and cud chewing, though the stomach is divided into three chambers.
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…of the stomach (the reticulum, omasum, and abomasum), where it is further digested with the aid of various essential microorganisms that live in the stomach. The pseudoruminant digestive process is very similar, also involving regurgitation and cud chewing, though the stomach is divided into three chambers.
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