pulse. The carotid artery only has one beat in the cardiac cycle. non-palpable – the JVP cannot be palpated. If one feels a pulse in the neck, it is generally the common carotid artery. occludable – the JVP can be stopped by occluding the internal jugular vein by lightly pressing against the neck. It will fill from above. JVP waveform The jugular venous pulsation has a biphasic waveform. The a wave corresponds to right atrial contraction and ends synchronously with the carotid artery pulse. The peak of the 'a' wave demarcates the end of atrial systole. The x descent follows the 'a' wave and corresponds to atrial relaxation and rapid atrial filling due to low pressure. The c wave corresponds to right ventricular contraction causing the closed tricuspid valve to bulge towards the right atrium during RV isovolumetric contraction. The x descent follows the 'c' wave and occurs as a result of the right ventricle pulling the tricuspid valve downward during ventricular systole (ventricular ejection/atrial relaxation). (As stroke volume is ejected, the ventricle takes up less space in the pericardium, allowing relaxed atrium to enlarge). The x' (x prime) descent can be used as a measure of right ventricle contractility. The v wave corresponds to venous filling when the tricuspid valve is closed and venous pressure increases from venous return – this occurs during and following the carotid pulse. The y descent corresponds to the rapid emptying of the atrium into the ventricle following the opening of the tricuspid valve. Quantification A classical method for quantifying the JVP was described by Borst & Molhuysen in 1952. It has since been modified in various ways. A venous arch may be used to measure the JVP more accurately. Moodley's sign This sign is used to determine which waveform you are viewing. Feel the radial pulse while simultaneously watching the JVP. The waveform that is seen immediately after the arterial pulsation is felt is the 'v wave' of the JVP. Abdominojugular test The term "hepatojugular reflux" was previously used as it was thought that compression of the liver resulted in "reflux" of blood out of the hepatic sinusoids into the inferior vena cava, thereby elevating right atrial pressure and visualized as jugular venous distention. The exact physiologic mechanism of jugular venous distention with a positive test is much more complex and the commonly accepted term is now "abdominojugular test". In a prospective randomized