Explain Jugular venous pressure and pulsation in details?

The jugular venous system is in direct continuity to right atrium in systolic extending to right ventricle in diastole when tricuspid valve is open. In other word its pressure and pattern of pulsation denotes the right sided filling pattern or preload. In absence of any pulmonary or right-sided disease state of heart may even be a good indirect indicator of left ventricular preload state.

Figure: Jugular venous pressure and pulsation

The pressure and pulsation pattern in internal jugular veins are clinically studied and not that of external jugular system, which takes a sharp bend to enter the subclavian vein which in turn has another bend before it drains into SVC. The internal jugular vein unlike its counterpart (external) cannot be seen. The silhouette of skin overlying the internal jugular vein can be studied hence this examination is always preferable to perform looking tangentially to root of neck, if necessary again with tangential illumination by a torch.