ANATOMY

Detailed explanation-1: -What are sinuses? The sinuses are cavities, or air-filled pockets, near the nasal passage. As in the nasal passage, the sinuses are lined with mucous membranes.

Detailed explanation-2: -Sinuses. These 4 pairs of air-filled cavities are also lined with mucous membranes. Sinuses make the skull lighter.

Detailed explanation-3: -One of many small hollow spaces in the bones around the nose. Paranasal sinuses are named after the bones that contain them: frontal (the lower forehead), maxillary (cheekbones), ethmoid (beside the upper nose), and sphenoid (behind the nose).

Detailed explanation-4: -Structure of the paranasal sinuses The paranasal sinuses are hollow spaces filled with air, located around the nose inside the skull. The paranasal sinuses are connected to one another and to the nasal cavity.