Pulmonary medicine is the subspecialty of internal medicine that focuses on the diagnosis and management of disorders of the respiratory system, including the lungs, upper airways, thoracic cavity, and chest wall. Although most common respiratory problems are treated by general internists and other specialty physicians, internists practicing pulmonary medicine (often referred to as “pulmonologists”) are frequently called upon to help diagnose unknown disorders and assist in managing difficult, unusual, or complicated diseases of the respiratory system.