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| Internal jugular vein | |
|---|---|
 The fascia and middle thyroid veins. (Internal jugular visible at center left.) | |
 Veins of thetongue. Thehypoglossal nerve has been displaced downward in this preparation. (Internal jugular visible at bottom left.) | |
| Details | |
| Drains from | Neck |
| Source | Sigmoid sinus andinferior petrosal sinus |
| Drains to | Brachiocephalic vein |
| Artery | Internal carotid,common carotid |
| Identifiers | |
| Latin | vena jugularis interna |
| TA98 | A12.3.05.001 |
| TA2 | 4800 |
| FMA | 4724 |
| Anatomical terminology | |
Theinternal jugular vein is a pairedjugular vein that collects blood from thebrain and the superficial parts of theface andneck. This vein runs in thecarotid sheath with thecommon carotid artery andvagus nerve.
It begins in the posterior compartment of thejugular foramen, at the base of theskull. It is somewhat dilated at its origin, which is called thesuperior bulb.
This vein also has a common trunk into which drains the anterior branch of theretromandibular vein, thefacial vein, and thelingual vein.
It runs down the side of the neck in a vertical direction, being at one end lateral to theinternal carotid artery, and then lateral to thecommon carotid artery, and at the root of the neck, it unites with thesubclavian vein to form thebrachiocephalic vein (innominate vein); a little above its termination is a second dilation, theinferior bulb.
Above, it lies upon therectus capitis lateralis, behind theinternal carotid artery and the nerves passing through thejugular foramen. Lower down, the vein and artery lie upon the same plane, theglossopharyngeal andhypoglossal nerves passing forward between them. Thevagus nerve descends between and behind thevein and theartery in the same sheath (thecarotid sheath), and theaccessory runs obliquely backward,superficial or deep to the vein.
At the root of the neck, theright internal jugular vein is a little distance from thecommon carotid artery, and crosses the first part of thesubclavian artery, while theleft internal jugular vein usually overlaps the common carotid artery.
The left vein is generally smaller than the right, and each contains a pair ofvalves, which exist about 2.5 cm above the termination of the vessel.
In 9–12% of the Western population, the size, shape or course of the internal jugular vein is abnormal.[1] Variants identified including veins markedly smaller, or not functionally present.[2] The mean diameter is 10 mm, but may range between 5 and 35 mm.[3]
The jugular veins are relatively superficial and not protected by tissues such asbone orcartilage. This makes them susceptible to damage. Due to the large volumes of blood that flow through the jugular veins, damage to the jugulars can quickly cause significant blood loss, which can lead to hypovolæmic shock and then death if not treated.
As there is one pair of valves between theright 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 thejugular 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:[4]
The JVP can also be artificially raised by applying pressure to the liver (thehepatojugular reflux). This method is used to locate the JVP and distinguish it from the carotid pulse. Unlike the carotid pulse, the JVP is impalpable.
As the internal jugular is large, central and relatively superficial, it is often used to placecentral 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).[5]
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 thecarotid artery, lung or thevagus nerve (CN X) are punctured, and damage is caused to these structures.
This article incorporates text in thepublic domain frompage 648 of the 20th edition ofGray's Anatomy(1918)
