Quincke's sign

The visualization of capillary pulsations as alternating blanching (whitening) and reddening of the nail bed on light compression in sync with the heartbeat. Classically associated with chronic severe aortic regurgitation, widened pulse pressur, hyperdynamic states (anemia, hyperthyroidism, pregnancy, liver cirrhosis, AV fistula, beriberi), and connective tissue disease (Marfan syndrome, Ehlers-Danlos syndrome).