The pretracheal fascia is the middle layer of the deep cervical fascia enclosing the anterior cervical viscera: the thyroid gland, trachea, and oesophagus. It is attached superiorly to the thyroid cartilage and hyoid, and inferiorly it is continuous with the fibrous pericardium in the mediastinum. It forms a sleeve around the thyroid gland (surgical capsule of the thyroid, separate from the true thyroid capsule).
Encases the anterior cervical viscera including the thyroid, trachea, and oesophagus, allows these structures to move together during swallowing, and provides the surgical dissection plane (between pretracheal fascia and investing fascia) in the anterior cervical approach.
The pretracheal fascia defines the surgical plane in thyroid surgery, where the strap muscles are separated along the midline and retracted to expose the pretracheal fascia over the thyroid. Entry into the fascial sleeve exposes the thyroid gland's surgical capsule. The retrosternal extension of a large goitre (substernal goitre) passes within the pretracheal fascial space into the superior mediastinum. Infection within the pretracheal space can descend into the anterior mediastinum (anterior mediastinitis) following deep neck infection or oesophageal perforation.
Oesophageal perforation from endoscopy or swallowed foreign body allows organisms to enter the pretracheal fascia space and descend into the anterior mediastinum, producing anterior mediastinitis with fever, chest pain, and mediastinal widening on CXR requiring urgent surgical drainage of the neck and mediastinum.
