Final answer:
The pressure below the vocal folds, or larynx, is known as subglottal pressure. This falls within the realm of respiratory pressure dynamics, which are important for understanding pulmonary ventilation and how it is influenced by atmospheric, intra-alveolar, and intrapleural pressures.
Step-by-step explanation:
The pressure that can be measured immediately beneath the level of the vocal folds or larynx is subglottal pressure. When discussing respiratory pressures, it is important to note that atmospheric pressure is the force exerted by gases present in the atmosphere. The pressure within the pleural cavity is known as intrapleural pressure, which is typically lower than intra-alveolar pressure, and the pressure within the alveoli, called intra-alveolar pressure (intrapulmonary pressure), always equalizes with the atmospheric pressure. Understanding these pressure dynamics is key to comprehending how pulmonary ventilation operates according to Boyle's law, which states that pressure increases as volume decreases.