The jugular venous pressure (JVP, sometimes referre to as jugular venous pulse) is the indirectly observed pressure over the venous system. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have been described. the upward deflections are the "a" (atrial contraction), "c" (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumic systole) and "v"= atrial venous filling. and the downward deflections of the wave are the "x"(the atrium relaxes and the tricuspid valve moves downward) and the "y" descent (filling of ventricle after tricuspid opening).