Palv minus Pbs corresponds to which pressure?

• A. Transrespiratory Pressure
• B. Transairway Pressure
• C. Transpulmonary Pressure
• D. Transthoracic Pressure

Answer: (D)

Palv minus Pbs is the pressure difference across the chest wall, known as the transthoracic pressure. It represents the force across the thoracic cage—the alveolar space on one side and the body surface on the other—driving the overall chest wall–lung system during breathing. This contrasts with transpulmonary pressure, which is Palv minus pleural pressure and reflects the distending force on the lung tissue itself, and with other gradients that describe pressures across the airways or the respiratory system as a whole. So the difference between alveolar pressure and body surface pressure corresponds to transthoracic pressure.