The trachealis muscle lies posterior to the trachea and anterior to the oesophagus.
[1] It bridges the gap between the free ends of C-shaped rings of cartilage at the posterior border of the trachea, adjacent to the oesophagus.
[3] The trachealis muscle also supports a thin cartilage on the inside of the trachea.
[5] The primary function of the trachealis muscle is to constrict the trachea, allowing air to be expelled with more force, such as during coughing.
[7] In infants, the insertion of an oesophagogastroduodenoscope into the oesophagus may compress the trachealis muscle, and narrow the trachea.