Space
Maxillary sinus
A large sinus between the orbit and upper teeth
High-yield
Maxillary drainage depends on ciliary transport, not simply gravity. The usual route passes through the ethmoidal infundibulum to the middle meatus.
Overview
Each maxilla contains an air-filled cavity that expands toward the cheek. Its broad medial surface faces the nose; the orbit is above it and the upper tooth-bearing process below. The lining transports mucus toward an opening high on the medial wall.
Reference facts
- Boundaries
- Roof: orbital floor; floor: alveolar process. The nasal wall forms the medial boundary; the facial surface is anterior, with the infratemporal and pterygopalatine regions behind.
- Contents
- Air and a mucus-producing respiratory lining with motile cilia.
- Communications
- Natural ostium to the ethmoidal infundibulum and middle meatus; additional openings occur in some people.
- Blood supply
- Maxillary artery branches, particularly posterior superior alveolar and infraorbital branches, with posterior lateral nasal contributions to the medial lining.
- Innervation
- Superior alveolar and infraorbital branches of the maxillary division of the trigeminal nerve (V2).
Clinical correlation
The distance between posterior tooth roots and the sinus varies considerably. Dental infection can involve the sinus, while sinus inflammation may be perceived as upper tooth pain; symptoms alone do not establish the source.
Frequently asked questions
What are the boundaries of the maxillary sinus?
Roof: orbital floor; floor: alveolar process. The nasal wall forms the medial boundary; the facial surface is anterior, with the infratemporal and pterygopalatine regions behind.
What does the maxillary sinus contain?
The maxillary sinus contains the air and a mucus-producing respiratory lining with motile cilia.
What does the maxillary sinus communicate with?
Natural ostium to the ethmoidal infundibulum and middle meatus; additional openings occur in some people.