windpipes

Windpipe is the common name for the trachea, a flexible cartilaginous tube that conducts air from the larynx to the bronchi. In humans it lies in the neck and upper chest, anterior to the esophagus, and extends from the lower margin of the cricoid cartilage to roughly the level of the sternal angle, where it divides into the left and right main bronchi.

Structure and lining: The trachea is about 10 to 12 centimeters long in adults and is supported by C-shaped rings of hyaline cartilage that keep the airway open. The open posterior wall is completed by the trachealis muscle and dense connective tissue. The inner lining consists of pseudostratified ciliated columnar epithelium with goblet cells; cilia beat toward the larynx to move mucus and trapped particles upward, a mechanism called mucociliary clearance.

Function and branching: The trachea serves as the main conducting airway, warming, humidifying, and filtering inspired air. It also participates in defense through coughing and mucociliary action. At its inferior end, it bifurcates into the left and right main bronchi at a region called the carina.

Clinical notes: The windpipe can be affected by inflammation (tracheitis), narrowing (tracheal stenosis), or trauma. It is a common site for endotracheal intubation and, when long-term airway access is needed, tracheostomy. Anatomical variations exist among individuals and species.