The posterior tracheal band: a reflector of local superior mediastinal abnormality

The posterior tracheal band (PTB) is a thin band of uniform width consisting primarily of the posterior tracheal wall which is observed almost constantly in a well-positioned and exposed lateral view of the chest. It is formed by two interfaces; and internal junction line between the inner tracheal wall and air in the lumen, and an external junction line between the adventitial surface of the right posterior wall (with paper-thin mediastinal covering) and aerated lung in the right retrotracheal recess. Any pathological process in the mediastinum, pleura or right upper lobe medially which affects the external interface causes an alteration or disappearance of the PTB. Anatomical studies explaining the formation of the PTB and clinical cases showing its alteration or disappearance are presented.