Sinuses

Synonyms

Paranasal sinuses

Definition

The paranasal sinuses comprise of the ethmoid sinus, frontal sinus, maxillary sinus, and sphenoid sinus.

Structure

The nasal sinuses are lined with pseudostratified ciliated columnar respiratory epithelium with many goblet cells. They arise from and drain into the nasal cavity. The drainage is facilitated by cilia hairs.

The paranasal sinuses surround the nasal cavity and drain into the nasal cavity. The nasal wall is composed of the superior, middle, and inferior turbinates that appear as bulbous projections into the central space. The turbinates divide the nasal cavity into three air passages: the superior, middle, and inferior meati. These are inferior to each respective turbinate.

The frontal sinus is not seen radiographically until the sixth year of life, and pneumatization is not complete until early adulthood. The frontal sinus empties into the middle meatus. The right and left frontal sinuses are separated by the intersinus septum.

The...