Maxillary sinus: the cavity in the maxilla and the cheekbone
- Highlighted area
Quick facts
- Definition
- Paired air cavity inside the maxilla, the largest of the paranasal sinuses.
- Location
- Under the cheek, below the orbit and above the roots of the upper teeth.
- Drainage
- Communicates with the nasal cavity through an opening in the medial wall of the sinus.
- Relevance in facial harmonization
- Helps explain the bony base of the cheekbone and why the infraorbital area and the cheek call for anatomical attention.
The maxillary sinus is an air cavity located inside the body of the maxilla, on each side of the nose. It is the largest of the paranasal sinuses and is roughly pyramid-shaped. It lies below the orbit, behind the cheek and above the roots of the upper teeth, and communicates with the nasal cavity through an opening in the medial wall.
What are its boundaries?
The layout of this cavity explains its clinical importance:
| Wall | Related structures |
|---|---|
| Superior (roof) | Floor of the orbit, with the infraorbital canal through which the nerve runs |
| Anterior | Face of the maxilla, under the cheek, with the canine fossa |
| Inferior (floor) | Roots of the upper molars and premolars |
| Medial | Lateral wall of the nose, with the drainage opening |
| Posterior | Infratemporal region and deep vessels |
The infraorbital nerve runs in the roof of the sinus, inside the canal, and exits through the infraorbital foramen on the face. This closeness is why maxillary sinus infections can show up as pain or numbness in the cheek.
What is the relationship to the cheekbone?
The cheek bone is formed by the joining of the maxilla with the zygomatic bone, through the zygomatic process of the maxilla. The maxillary sinus occupies the body of the maxilla just below this region. The volume of the cavity and the thickness of its walls vary, which contributes to the difference in projection between people.
In cases of malar hypoplasia, the bony base is less projected. Assessment of the cheek must take into account that bone is the limit: soft tissue can be shaped, but the structure that supports it has little room for change.
Precautions and warning signs
Active maxillary sinusitis, with facial pain, nasal discharge and a feeling of pressure, is a reason to postpone procedures in the central face and have the patient seen by a physician. Patients with a history of sinus surgery, trauma or dental implants in the upper jaw should have this information recorded in the medical history.
The infraorbital artery and nerve, the facial vein and the deep fat of the cheek form a territory of complex anatomy, and injection in the cheekbone area requires detailed knowledge of the planes and vessels.
Also called: antrum of Highmore (old term), paranasal maxillary sinus.
Frequently asked questions
Does the maxillary sinus influence cheekbone projection?
Yes, in part. It occupies the body of the maxilla and is part of the bony framework that supports the midface. Its size and position vary between people and affect the base on which soft tissue rests.