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Jugular venous pulse
What does the 'c' wave of the jugular venous pulse represent?
- A. Passive atrial filling against a closed tricuspid valve
- correctB. Bulging of the closed tricuspid valve into the right atrium during isovolumetric ventricular contraction
- C. Opening of the tricuspid valve with rapid ventricular filling
- D. Right atrial contraction at the end of diastole
Explanation
Key fact
a is atrial contraction, c is the tricuspid valve bulging back, v is atrial filling. The descents are x after c and y after v.
Bulging of the closed tricuspid valve into the right atrium during isovolumetric ventricular contraction. The ventricle pushes the shut valve backwards.
Why
Ventricular systole begins with the tricuspid valve already closed.
Pressure rises sharply before the pulmonary valve opens - isovolumetric contraction.
The shut valve is pushed back towards the atrium.
That transient rise in atrial pressure is the c wave.
It is followed by the x descent as the atrium relaxes and the base descends.
Reading the jugular venous pulse
| Wave | Event |
|---|---|
| a | Right atrial contraction, end diastole |
| c | Tricuspid bulging in isovolumetric ventricular contraction |
| x descent | Atrial relaxation and descent of the valve base |
| v | Atrial filling against a closed tricuspid valve |
| y descent | Tricuspid opens, ventricle fills rapidly |
The c wave is the shut tricuspid valve bulging back during isovolumetric contraction
Why not the others
- A. Passive atrial filling against a closed tricuspid valve — is the v wave, which becomes a giant systolic wave in tricuspid regurgitation.
- C. Opening of the tricuspid valve with rapid ventricular filling — is the y descent, which is sharp in constrictive pericarditis and blunted in tamponade.
- D. Right atrial contraction at the end of diastole — is the a wave. It is absent in atrial fibrillation and giant in tricuspid stenosis.
Remember
a, c, v - atrium, closure, filling. Then x and y are the two descents that follow c and v.
Go deeper
Cannon a waves occur when the atrium contracts against a closed tricuspid valve - irregular in complete heart block, regular in a junctional rhythm.
A steep y descent with a raised pressure is constrictive pericarditis; an absent y descent is cardiac tamponade.
Kussmaul's sign - the venous pressure rising on inspiration - is seen in constriction, not in tamponade.
Ganong's Review of Medical Physiology, 27th ed. (McGraw Hill, 2025); Harrison's Principles of Internal Medicine, 22nd ed. (McGraw Hill, 2025).