Plural of antrum; medical/anatomical term for cavities or hollow spaces within the body, especially in bones or organs.
From Latin antrum, meaning a cave or cavern, ultimately from Greek antron. The Romans used the term to describe enclosed spaces or grottos, and medical terminology adopted it for internal body cavities. The plural 'antra' follows Latin declension patterns.
The maxillary antrum (a sinus cavity in your cheekbones) is why you feel sinus pain in your teeth! The Roman metaphor of 'cave' is perfect—these antral cavities are indeed like small caves within our skulls, and they're a major source of medical complications and sinus infections.
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