the air-filled spaces, lined with mucous membrane, within some of the bones of the skull. They open into the nasal cavity, via the meatuses, and are named according to the bone in which they are situated. They comprise the frontal sinuses and the maxillary sinuses (one pair of each), the ethmoid sinuses (consisting of many spaces inside the ethmoid bone), and the two sphenoid sinuses.
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sinus paranasales [TA] the mucosa-lined air cavities in the cranial bones that communicate with the nasal cavity, including the ethmoidal, frontal, maxillary, and sphenoid sinuses.
Sinus paranasales (paranasal sinuses).
Medical dictionary. 2011.