carotid sinus An enlarged region of the carotid artery at its major branching point in the neck. Its walls contain many receptors that are sensitive to changes in pressure and it regulates blood pressure by initiating reflex changes in heart rate and dilation of blood vessels.

carotid sinus n. a pocket in the wall of the carotid artery, at its division in the neck, containing receptors that monitor blood pressure (baroreceptors).