The maxillary sinus (or antrum of Highmore) is a paired pyramid-shaped paranasal sinus within the maxillary bone which drains via the maxillary ostium into the infundibulum, then through hiatus semilunaris into the middle meatus. It is the largest of the paranasal sinuses.

Summary

• location: paired sinuses within the body of the maxilla

• blood supply: small arteries from the facial, maxillary, infraorbital and greater palatine arteries

• innervation: anterior, middle and posterior superior alveolar, greater palatine and infraorbital nerves

Gross anatomy

Described as a pyramid, the maxillary sinuses have a base on the lateral border of the nose, with the apex pointing towards the zygomatic process of the maxilla. The floor is formed by the alveolar process of the maxilla. The roof is the orbital floor. The posterior wall forms the anterior border of the pterygopalatine fossa.

There are several recesses of the maxillary sinus ⁵:

• infraorbital recess (superiorly)

• zygomatic recess (laterally)

• alveolar recess (inferiorly)

• palatine recess (variable extension of alveolar recess)

Like the other paranasal air sinuses, these can vary in size. Large maxillary sinuses can extend to the alveolar process of the maxilla to the point where the roots of the molar teeth can project into the space.

Unlike the other paranasal air sinuses, the opening of the sinus is found on its superior end. This ostium communicates with the nasal cavity via the posterior end of the hiatus semilunaris.

Arterial supply

Small arteries from the facial, maxillary, infraorbital and greater palatine arteries pierce the bony walls of the maxillary sinus.

Venous drainage

Venous drainage anteriorly is via the sphenopalatine vein and posteriorly via the pterygoid venous plexus and the facial vein.

Lymphatic drainage

Lymph from the maxillary sinus drains to the submandibular group of lymph nodes via the infraorbital foramen or the aforementioned communication with the nasal cavity. 

Innervation

• superior alveolar nerves

  • posterior superior alveolar nerves: dental branches pierce the bone to supply the sinus mucosa

  • middle superior alveolar nerves: supply the pre-molar teeth and overlying mucosa of the sinus

  • anterior superior alveolar nerves: supplies canine and incisors and anterior wall of the sinus

• greater palatine nerve

  • minute branches from this nerve supply the medial wall of the sinus

• infraorbital nerve

  • perforating branches supply the roof of the sinus

Variant anatomy

Common anatomic variations of maxillary sinuses are ⁶:

• pneumatisation into the roots of teeth (83.2%)

• antral septations (44.4%)

• hypoplasia (4.8%)

• exostosis (2.6%)

• total maxillary sinus agenesis - rare

Development

It is present at birth and it develops until around the age of 14 years.

History and etymology

The antrum Highmorianum was first described by Nathaniel Highmore (1613-1685), a British physician and anatomist ³.

Related pathology

• neoplastic

  • inverted papilloma

  • antral carcinoma

• infections and inflammation

  • sinusitis

    • more than 70% of unilateral maxillary sinusitis can be attributed to an odontogenic cause ⁴

    • fungal sinusitis

  • retention cysts

  • sinonasal polyposis

• others

  • silent sinus syndrome