Lung Exam

Excerpt

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.

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.