Which principle describes the relationship between area, velocity, and pressure at a stenosis?

Which principle describes the relationship between area, velocity, and pressure at a stenosis?

• A. Bernoulli principle
• B. Poiseuille's law
• C. Ohm's law
• D. Venturi effect

Answer: (A)

In a narrowed vessel, the flow has to speed up as the cross-sectional area decreases to keep the same volume flowing per unit time. Bernoulli's principle describes what happens then: as velocity increases along the streamline, the static pressure decreases. So at a stenosis, the area reduction drives a higher velocity through the narrowed segment and a drop in pressure, creating a pressure gradient across the stenosis. This relationship is the basis for understanding Doppler findings—higher velocity at the narrowing corresponds to lower pressure there. The Venturi effect is a specific way this same idea can manifest in a constricted tube, but Bernoulli’s principle is the general concept that links area, velocity, and pressure. Poiseuille's law and Ohm's law don't capture this direct, dynamic relationship in a stenosis.

In a narrowed vessel, the flow has to speed up as the cross-sectional area decreases to keep the same volume flowing per unit time. Bernoulli's principle describes what happens then: as velocity increases along the streamline, the static pressure decreases. So at a stenosis, the area reduction drives a higher velocity through the narrowed segment and a drop in pressure, creating a pressure gradient across the stenosis. This relationship is the basis for understanding Doppler findings—higher velocity at the narrowing corresponds to lower pressure there. The Venturi effect is a specific way this same idea can manifest in a constricted tube, but Bernoulli’s principle is the general concept that links area, velocity, and pressure. Poiseuille's law and Ohm's law don't capture this direct, dynamic relationship in a stenosis.