Hill's sign

The marked elevation of popliteal systolic arterial pressure compared with brachial systolic pressure (≥20-40 mmHg, and often ≥60 mmHg) in patients with chronic aortic regurgitation. Possible causes are age-related valve degeneration, congenital defects, aortic root dilation, infective endocarditis, rheumatic heart disease, and aortic dissection or aneurysm.