ethmoid sinus(redirected from Ethmoidal cells)
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Related to Ethmoidal cells: ethmoid air cell
An air cavity or space within the ethmoid bone, opening into the nasal cavity.
Any of the 3-18 paranasal sinuses on each side of the skull in and adjacent to the ethmoid bone. The ethmoid sinuses can be categorized as anterior, middle, or posterior, with each group usually draining into a different part of the nasal cavity. Ethmoid sinuses have very thin walls and are interconnected via openings in the septa between the sinuses.
See also: sinus
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