General Medical Information

Nasal Anatomy

Sharen J. Knudsen
Byron J. Bailey

The nasal skeleton consists of two paired nasal bones, the nasal process of the maxilla, and the upper and lower lateral cartilages. The septum is composed of the vomer, perpendicular plate of the ethmoid bone, and the quadrangular cartilage. The three paired turbinates, the ethmoid air cells, and the sphenoid bone form the endonasal skeleton.

The nasopharynx is the space from the choanae to the free edge of the soft palate. This rigid space contains the eustachian tube orifice, the Rosenmüller fossa, and the adenoid lymph tissue. The sphenoid fossa, which is posterosuperior to the insertion of the middle turbinate, houses the ganglion that bears the same name. Two important embryologic defects can occur in the nasopharynx. Rathke pouch is a remnant of the invagination of ectoderm that forms the anterior pituitary gland. Cysts of Rathke pouch are located high in the nasopharynx near the sphenovomer junction. The cysts can become infected. Tumors in this region are called craniopharyngioma and are composed of well-differentiated epithelial elements. Although the bulk of these tumors extend intracranially, they can occur in the nasopharynx. Symptoms include nasal obstruction with neurologic signs of visual field defects, extraocular motility disorders, and hypopituitarism. Treatment consists of surgery or radiation therapy.

The nasopharyngeal bursa of Tornwaldt is inferior to the Rathke pouch and is a remnant of the caudal notochord. Jelly-like material that persists in this bursa can become infected. A swollen, infected bursa that manifests as a nasopharyngeal mass can rupture if manipulated.