In medicine,<unk>  is the exaggerated drop in diastolic central venous pressure seen in constrictive pericarditis (particularly with a stiff calcified pericardium) and manifested as abrupt collapse of the neck veins or marked descent of the central venous pressure waveform. The sign is named after Nikolaus<unk> .
Friedreich's sign
Prehn's sign
Carvallo's sign
Ladin's sign
Ballance's sign
Crowe sign
Darier's sign
Winterbottom's sign