Fig. 3.1 Jugular pressure contour.

Changes in jugular filling reflect changes in central venous pressure and can be useful indicators of normal and abnormal cardiac function.

Key: a wave is due to right atrial (RA) contraction; c wave is due to closure of the tricuspid valve (TV) at the onset of systole; V wave is caused by a rise in RA pressure during systole due to continued venous return while the TV is closed; h wave is caused by a rise in RA pressure during diastasis due to continued venous return; x descent is due to RA relaxation; x' trough is caused by the ventricle pulling the AV valve ring towards the apex resulting in reduced pressure in the RA; y descent is due to the drop in RA pressure when the TV opens in early diastole.