label: Maxillary Sinus
label_lc: maxillary sinus
description: "A pyramidal-shaped, thin-walled, air-filled cavity located in the maxilla. It is lined by mucus membrane and periosteum (mucoperiosteum) which contains cilia. It is adjacent to the nasal cavity and communicates with the middle meatus of the nose. It is the largest paranasal sinus and is composed of three recesses: alveolar, zygomatic, and infraorbital."