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Rene Laënnec's invention of the stethoscope in the early 1800s paved the way for the clinical examination of the lungs. The lung exam is a standard approach for comprehensive and focused physical examinations in patients. Due to their proximity to vital structures such as the heart, great vessels, esophagus, and diaphragm, a careful examination of the lungs can offer valuable insights for differential diagnoses. The airway extends from the trachea to the bronchus for each lung segment and to the smallest structure for air exchange, called the bronchioles. The airway continuity is derived from the embryonic foregut and is divided into the trachea, bronchi, and bronchioles. Although humans have 2 lungs, they are not symmetrical; the right lung is bigger compared to the left. The right lung comprises 3 lobes and 10 segments, whereas the left has 2 lobes and 9 segments. The segmental division of the lungs is based on their airway supply.[1][2] The physical examination of the chest consists of inspection, palpation, percussion, and auscultation. Although clinicians may skip the first 3 steps of the chest auscultation, a thorough lung examination can reveal important pertinent positives or negatives for further evaluation. Depending on the experience of the examining clinician and the acuity of the case, certain parts of the examination are more important compared to others. Several technological advances have also reduced the necessity for manual completion of each part of the exam. Currently, digital stethoscopes are utilized by some clinicians to facilitate higher accuracy of changes in lung sounds and differentiation of lung sounds.

Within clinical training or further practice, the standardized lung exam typically includes inspection, palpation, percussion, and auscultation. However, the order and sequence are integrated or tailored to the patient's case based on the clinician's experience. For example, auscultating takes priority over percussion in a patient losing an airway. Similarly, inspection may be the only feasible part of the lung exam for a patient who refuses a physical exam. The process of conducting a lung exam varies from one facility to another. In teaching institutions, students or early trainees often perform the exam under the guidance of a senior clinician, repeating the more complex parts. Interprofessional collaboration between clinicians at varying training levels integrates manual methods with recent developments in digital and software-driven approaches. In particular, the role of environmental noise in interfering with accurate manual readings could be reduced. Integrating manual and digital methods is still a topic of research.[15][16][17] Although integrated approaches are in progress, the decision to complete each part of the exam in sequence is still the didactic method.