Browse the corpus

The airway comprises the passages of the respiratory tract that conduct air from the external environment to the alveoli. This conduit extends from the nares and oral opening to the terminal bronchioles, where gas exchange occurs within the alveolar respiratory units. The airway is divided into upper and lower portions, each with distinct anatomical structures and specialized functions.[1][2][3] In addition to conducting airflow, the airway filters, humidifies, and warms inspired air, provides defense against pathogens through mucosal and lymphoid tissues, and contributes to phonation and olfaction.[4] Airway anatomy underpins clinical practice in anesthesia, emergency care, trauma, and respiratory disease, where patency is fundamental to oxygenation and survival. Anatomical detail also frames surgical practice, shaping approaches to endotracheal intubation, cricothyrotomy, and tracheostomy, and influencing outcomes in procedures involving the thyroid or tonsils, where adjacent structures or tissue hypertrophy may compromise the passage of air. Thorough knowledge of airway structure and function enables accurate assessment, supports safe device placement, guides management of developmental and acquired variations, and allows rapid, effective intervention in urgent situations.