In normal people, the external jugular vein is not revealed in standing or sitting position, and it is slightly filled when lying down, but it is limited to 2/3 of the distance from the upper edge of the clavicle to the angle of the jaw, if it is filled, distended and full when it exceeds the above level or 45 degrees in semi-recumbent position, it is called jugular vein anger, which indicates that the increase of venous pressure is an abnormal phenomenon. Jugular vein is the pressure gauge of right atrium, it can reflect the pressure change and volume change of right atrium, because the right jugular vein is shorter than the left jugular vein and it is the direct continuation of superior vena cava, so the right jugular vein can reflect the pressure change of right atrium more than the left. How to check the jugular vein when the patient is in the prone position, the physician examines the jugular vein to see if it is filled beyond the lower 2/3 of the distance from the superior clavicular border to the angle of the jaw. Or in the standing and sitting position to see if a significant venous filling can be seen. If this is present, it is seen in right heart failure, pericardial disorders and superior vena cava syndrome. Jugular venous pulsation, which is soft and diffuse and not pulsatile on palpation, is seen in tricuspid valve insufficiency. Clinical significance Abnormal findings: on examination, the jugular vein is found to be filled beyond the lower 2/3 of the distance from the superior clavicular border to the angle of the mandible in its prone position. Or significant venous filling is seen in the standing and sitting positions. It may be suffering from right heart failure, pericardial disease and superior vena cava syndrome. Jugular venous anger with positive jugular pulsation is seen in severe congestive right heart failure with severe tricuspid valve insufficiency (functional or organic), as well as systolic pulsation of the veins at the tips of the extremities (e.g., fingers) in response to cardiac contraction. Superior vena cava obstruction (superior vena cava obstruction syndrome) should be considered in cases of jugular venous anger without hepatic bruising and enlargement and/or lower extremity edema. People who need to be examined: routine physical examination items, people with vascular abnormalities.