antrum

1. A cavity or chamber, especially one in a bone.
2. Either of the sinuses in the bones of the upper jaw, opening into the nasal cavity.

[Late Latin, cavity in the body, from Latin, cave, from Greek antron.]

A maxillary sinus. A cavity in the maxilla, lined by ciliated columnar epithelium, the inferior border of which approximates the apices of the roots of the maxillary posterior teeth.

Pertaining to the antrum; usually the reference is to the pyloric antrum of the stomach. See also pylorus.

• a. peristalsis — responsible for the onward movement of ingesta through the pylorus; when the pylorus is closed the movements assist in the mixing and maceration of the stomach contents.

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