A sphygmomanometer ( / ˌ s f ɪ ɡ m oʊ m ə ˈ n ɒ m ᵻ t ər / SFIG -moh-mə- NOM -i-tər ), blood pressure meter , blood pressure monitor or blood pressure gauge is a device used to measure blood pressure , composed of an inflatable cuff to collapse and then release the artery under the cuff in a controlled manner, [1] and a mercury or mechanical manometer to measure the pressure