The paranasal sinuses are air-filled, rigid cavities in the bony substance of the human skull, which are lined with a protective epithelial layer (mucosa).
Basic knowledge for Open Water Diver* (OWD*)
The human boddy has four pairs of paranasal sinuses:
- sphenoidal sinuses
- ethmoid sinuses
- maxillary sinuses
The paranasal sinuses are connected to the nasopharynx and, in some cases, to one each other by means of a canal system. In the case of an inflammatory change caused by e. g. a cold or an infection the connection routes can be changed or even blocked. Since pressure must be equalized in the paranasal sinuses, just like in the middle ear, diving under this circumstances can lead to a barotrauma in the sinuses. Therefore, you should never go diving if you have a cold or infection.