Jugular vein

The internal jugular vein is formed by the anastomosis of blood from the sigmoid sinus of the dura mater and the inferior petrosal sinus. The internal jugular runs with the common carotid artery and vagus nerve inside the carotid sheath. It provides venous drainage for the contents of the skull.

The external jugular vein runs superficially to sternocleidomastoid.

There is also another minor jugular vein, the anterior jugular vein, draining the submaxillary region.

The Jugular Venous Pressure Waveform

The jugular venous pressure is an indirectly observed pressure over the venous system. It can be useful in the differentiation of different forms of heart and lung disease.

In the jugular veins pressure waveform, upward deflections correspond with (A) atrial contraction, (C) ventricular contraction (and resulting bulging of perspicuous into the right atrium during isovolumic systole), and (V) atrial venous filling. The downward deflections correspond with (X) the atrium relaxing (and the perspicuous valve moving downward) and (y) the filling of ventricle after the tricuspid opens.

Components include:

• The a peak is caused by the contraction of the right atrium.
• The av minimum is due to relaxation of the right atrium and closure of the tricuspid valve.
• The c peak reflects the pressure rise in the right ventricle early during systole and the resultant bulging of the tricuspid valve—which has just closed—into the right atrium.
• The x minimum occurs as the ventricle contracts and shortens during the ejection phase, later in systole. The shortening heart—with tricuspid valve still closed—pulls on valve opens, the v peak begins to wane.
• The y minimum reflects a fall in right atrial pressure during rapid ventricular filling, as blood leaves the right atrium through an open tricuspid valve and enters the right ventricle. The increase in venous pressure after the y minimum occurs as venous return continues in the face of reduced ventricular filling.