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barosinusitis bar·o·si·nus·i·tis (bār'ō-sī'nə-sī'tĭs)
pain, inflammation, and possible bleeding of the membranes lining the sinus cavities in the head, caused by a difference between the pressure inside the sinuses and that outside. Sinus squeeze is a common malady of persons flying in unpressurized aircraft and of divers.