a tracheal tube has a cuff surrounding its exterior for being filled with liquid or air to expand the cuff against a patient &# 39 ; s trachea to provide a sealed air passage through the tube into the patient &# 39 ; s lungs . the cuff , in its expanded configuration , has a bulbed anterior portion which seals against the trachea , and a narrow , elongated posterior portion extending distally away from the bulb . the cuff configuration allows the cuff to stay in a fixed position in the trachea during use , which reduces trauma and irritation to the patient .