eustachiantube

The Eustachian tube, or pharyngotympanic tube, is a narrow canal that connects the middle ear to the upper throat (nasopharynx). Its primary role is to equalize air pressure on both sides of the eardrum, ventilate the middle ear, and drain secretions from the middle ear into the nasopharynx.

Anatomy: In adults the tube measures about 36-38 mm and comprises a bony lateral one-third and a flexible cartilaginous medial two-thirds. The lumen is normally closed and opened intermittently by the action of the tensor veli palatini and levator veli palatini muscles during swallowing, yawning, and chewing.

Development and variation: In children the tube is shorter, more horizontal, and more susceptible to obstruction, contributing to higher rates of otitis media with effusion during early childhood.

Function: It acts as a passive conduit for pressure equalization, protects the middle ear from nasopharyngeal secretions, and allows drainage of middle ear fluid.

Pathology: Dysfunction of the tube (ETD) can result from inflammation, allergies, infection, or anatomical blockages, leading to a sensation of fullness, muffled hearing, ear pain, tinnitus, or recurrent ear infections. Barotrauma can occur with rapid pressure changes when the tube fails to equilibrate pressure.

Treatment and management: Management focuses on treating underlying inflammation or infection and improving tube function through intranasal corticosteroids, antihistamines, or decongestants as appropriate; nasal irrigation; autoinflation techniques. In persistent cases, procedures may be considered such as tympanostomy tube placement or balloon dilation of the Eustachian tube. Balloon dilation is a specialized procedure with variable success.

Etymology: The tube is named after Bartolomeo Eustachi, who described it in the 16th century.