Final answer:
Inflammation of the pleura, or pleurisy, can create increased pressure in the thoracic cavity and reduce lung volume, causing pain. During a physical exam, a characteristic friction rub sound can be heard if the pleurae are inflamed.
Step-by-step explanation:
Inflammation of the pleura, known as pleurisy, occurs when the layers of tissue covering the lungs become inflamed. The pleura consists of the visceral pleura that covers the lungs and the parietal pleura that lines the interior of the thorax. In pleurisy, this inflammation can cause painful symptoms because it increases the pressure within the thoracic cavity and reduces the lung volume, which can be detected during a physical examination.
Auscultation, using a stethoscope, might reveal a characteristic friction rub sound as the pleurae move against each other during breathing if there is not enough lubricating fluid, or less commonly, other abnormal lung sounds, such as crackles, if there is associated fluid. This condition should not be confused with other inflammatory diseases of the respiratory system, like pneumonia, which affects the alveoli and can present with symptoms such as coughing, chest pain, and difficulty breathing. However, pleurisy has a distinct presentation and requires specific medical evaluation and treatment.