ABSTRACT
A seemingly simple, single-lumen structure, the trachea is the sole conduit between the supraglottic airway and the lungs. Humidified and warmed air inspired through the nose travels to the lungs through the relatively thin-walled trachea, which widens slightly at its distal end. At birth, its diameter is approximately 0.5 cm. Tracheal size grows proportionally with the height and weight of the child [1,2]. In a male human adult, the trachea is approximately 12-cm long and 1.5-to 2-cm wide. In an adult female it is approximately 11-cm long and narrower. At its distal end, the carina, it bifurcates into the two mainstem bronchi (Figure 33.1).
