maxillarsinus

Maxillarsinus, commonly known as the maxillary sinus, is one of the paranasal sinuses. Each side of the nasal cavity houses a roughly pyramidal air-filled cavity within the maxillary bone, bordered by the orbital floor, cheek, nasal cavity, and the alveolar process that contains the upper teeth.

Anatomically, the maxillary sinus has a medially oriented wall that opens into the middle meatus of the nasal cavity via the maxillary ostium, forming part of the ostiomeatal complex. Its floor is closely related to the roots of the upper premolar and molar teeth, and the inferior wall forms part of the alveolar process. The lateral wall is near the zygomatic bone. The sinus is lined by respiratory mucosa composed of ciliated mucous epithelium which facilitates mucociliary clearance.

Developmentally, the maxillary sinuses are present at birth as small, mostly underdeveloped spaces that enlarge with age, typically reaching near their adult size in adolescence. The sinus volume varies among individuals and can be asymmetric or exhibit septa.

Functions attributed to the maxillary sinus include reducing skull weight, warming and humidifying inspired air, and contributing to voice resonance; the precise protective or communicative roles are not fully defined.

Clinical significance includes susceptibility to sinusitis (acute or chronic), often secondary to infection, allergic rhinitis, or dental pathology. Dental infections or procedures in the upper jaw can extend to the sinus, and sinus floor elevations are performed in dental implantology. Imaging with CT or CBCT is commonly used to assess anatomy, disease, or planning for procedures.