Pressure-volume relationship for an artery (solid curve) including positive and negative transmural pressures. Dashed triangles have equal bases indicating the range of transmural pressure (internal artery blood pressure minus cuff pressure) that determines the change in volume with each pulse. (a) Cuff pressure well above systolic with net distending pressure always negative. (b) Cuff pressure close to systolic. (c) Cuff pressure near mean arterial pressure with maximal volume changes. (d) Cuff pressure just below diastolic. (e) Cuff pressure well below diastolic.