cause significant blood loss, which can lead to hypovolæmic shock and then death if not treated. Jugular venous pressure As there is one pair of valves between the right atrium of the heart and the internal jugular, blood can flow back into the internal jugular when the pressure in the atrium is sufficiently high. This can be seen from the outside, and allows one to estimate the pressure in the atrium. The pulsation seen is called the jugular venous pressure, or JVP. This is normally viewed with the patient at 45 degrees turning his/her head slightly away from the observer. The JVP can be raised in a number of conditions: right ventricular failure (heart failure), tricuspid stenosis tricuspid regurgitation cardiac tamponade The JVP can also be artificially raised by applying pressure to the liver (the hepatojugular reflux). This method is used to locate the JVP and distinguish it from the carotid pulse. Unlike the carotid pulse, the JVP is impalpable. Catheterization As the internal jugular is large, central and relatively superficial, it is often used to place central venous lines. Such a line may be inserted for several reasons, such as to accurately measure the central venous pressure or to administer fluids when a line in a peripheral vein would be unsuitable (such as during resuscitation when peripheral veins are hard to locate). Because the internal jugular rarely varies in its location, it is easier to find than other veins. However, sometimes when a line is inserted the jugular is missed and other structures such as the carotid artery, lung or the vagus nerve (CN X) are punctured, and damage is caused to these structures. Additional images See also Jugular vein References Veins of the head and neck