The maxillary sinus (latin: sinus maxillaris) is the largest of the sinuses, filling the body of the maxilla. It is somewhat pyramidal in shape. The bilateral maxillary sinuses are located lateral to the nasal cavities and under the orbits.
Each maxillary sinus opens into the middle nasal meatus of the nasal cavity with an opening called the maxillary hiatus..
The six borders or walls of the maxillary sinus are formed by the following parts of the maxilla:
- medial: nasal surface of the maxilla (also forming the lateral wall of the nasal cavity);
- lateral: zygomatic process of the maxilla;
- inferior: alveolar process and part of the palatine process of the maxilla;
- superior: orbital surface of the maxilla (also forming the floor of the orbit);
- anterior: facial or anterior surface of the maxilla;
- posterior: infratemporal surface of the maxilla.
The arterial blood supply to the maxillary sinus is provided by several arteries, including:
- superior anterior, middle and posterior alveolar arteries,
- infraorbital artery,
- greater palatine artery.
The sensory innervation of the mucosa of the maxillary sinus is provided by the following nerves:
- posterior superior alveolar nerve,
- middle superior alveolar nerve,
- anterior superior alveolar nerve,
- infraorbital nerve.