Ethmoidal sinus refers to a group of small air-filled spaces located between the nasal cavity and the eye sockets. These sinuses, which are lined with mucous membranes, play an important role in moistening and filtering the air we breathe. Synonyms for ethmoidal sinus include the ethmoid sinus, ethmoid air cells, and ethmoidal labyrinth. These terms are often used interchangeably to describe this complex network of interconnected cavities. Regardless of what you call them, it's important to understand the significance of the ethmoidal sinuses in maintaining our respiratory health and overall well-being.