Internal jugular vein (vena jugularis interna): course, relations and central line anatomy

What it is

The internal jugular vein is the main vein draining the head and neck.

Location

It starts at the jugular foramen as the continuation of the sigmoid sinus, descends in the carotid sheath lateral to the carotid arteries and joins the subclavian vein behind the medial end of the clavicle to form the brachiocephalic vein. Tributaries include the inferior petrosal sinus and the facial, lingual, pharyngeal, and superior and middle thyroid veins.

Function

It drains the brain, face and neck.

Body system

Cardiovascular · paired (left and right)

FMA ID

FMA4762 (Foundational Model of Anatomy)

Key facts

• Its pulsations (jugular venous pressure) are seen between the two heads of sternocleidomastoid and reflect right atrial pressure.

Clinical relevance

It is a common site for central venous catheter placement.

The internal jugular vein begins in the posterior part of the jugular foramen, under the floor of the middle ear cavity, where it continues from the sigmoid sinus. Its first part is widened into the superior bulb of the internal jugular vein. It then runs almost vertically down the neck. Just before it ends, it usually widens again into the inferior bulb. (Kenhub: Internal jugular vein.)

Radiopaedia describes the vein as formed by the union of the sigmoid sinus and the inferior petrosal sinus in or just below the jugular foramen, the junction forming the jugular bulb. The sigmoid sinus ends in this bulb in the posterior half of the foramen. (Radiopaedia: Internal jugular vein.)

In the neck the vein lies deep to sternocleidomastoid. It descends in the carotid sheath lateral to the common carotid artery, and its inferior bulb contains a valve that stops blood flowing back up into the vein. At the root of the neck, behind the sternal end of the clavicle, it joins the subclavian vein to form the brachiocephalic vein. (TeachMeAnatomy: Venous Drainage of the Head and Neck.)

The carotid sheath is a tube of deep cervical fascia that runs from the skull base to the aortic arch. Above the hyoid bone it contains the internal carotid artery and the internal jugular vein, with the glossopharyngeal, vagus, accessory and hypoglossal nerves. Below the hyoid it contains the common carotid artery, the internal jugular vein and the vagus nerve, with the ansa cervicalis in its front wall and the deep cervical lymph nodes along it. (Radiopaedia: Carotid space.)

Within the sheath in the lower neck, the vein lies lateral to the common carotid artery, with the vagus nerve between the two. (Radiopaedia: Common carotid artery.)

The relation to the internal carotid artery changes with height: at C2 the vein lies behind the artery, at C3 posterolateral and at C4 lateral, and the vagus nerve is always between them. In front, the vein is crossed in its upper third by the accessory nerve, in its middle third by the lower root of the ansa cervicalis, and in its lower third it is covered by sternocleidomastoid and the tendon of omohyoid. Behind it, from above down, lie the lateral mass of the atlas, scalenus medius, scalenus anterior, the phrenic nerve, the first part of the subclavian artery and the pleura at the apex of the lung. (Radiopaedia: Internal jugular vein.)

Low in the neck the vein usually descends behind the gap between the sternal and clavicular heads of sternocleidomastoid before it enters the thorax. (Radiopaedia: Internal jugular vein.)

Radiopaedia lists the tributaries as the inferior petrosal sinus and sigmoid sinus at its origin, then the pharyngeal veins, the common facial vein (which carries the facial vein and the anterior branch of the retromandibular vein), the lingual vein and the superior and middle thyroid veins. Its mnemonic, "Medical Schools Let Fun People In", lists them from below upwards: middle thyroid, superior thyroid, lingual, facial, pharyngeal and inferior petrosal. (Radiopaedia: Internal jugular vein.)

Kenhub adds smaller tributaries: meningeal veins, the vein of the cochlear duct, the pharyngeal venous plexus and a vein from sternocleidomastoid. Through these tributaries the internal jugular vein drains the brain, the anterior face, the thyroid, larynx, trachea, oesophagus and neck muscles. (Kenhub: Internal jugular vein.)

Most of the blood from the brain reaches the vein through the dural venous sinuses. The transverse sinuses drain into the sigmoid sinuses, which leave the skull as the internal jugular veins. (Radiopaedia: Sigmoid sinus.)

The external jugular vein is a smaller, superficial vein. It forms within the parotid gland near the angle of the mandible from the posterior division of the retromandibular vein and the posterior auricular vein, runs down under the skin on the surface of sternocleidomastoid, and drains into the subclavian vein. The internal jugular vein, in contrast, lies deep to sternocleidomastoid inside the carotid sheath and drains into the brachiocephalic vein. (Radiopaedia: External jugular vein.)

OpenStax summarises the division of labour: blood from the brain and the superficial facial vein flows into the internal jugular vein, while blood from the more superficial parts of the head, scalp and cranial regions flows into the external jugular vein. (OpenStax Anatomy and Physiology 2e, 20.5: Circulatory Pathways.)

There is no jugular artery. People who search for the "jugular artery" usually mean the carotid artery, which runs with the internal jugular vein in the carotid sheath. (Radiopaedia: Common carotid artery.)

Pulsations of the internal jugular vein can be watched in the neck to estimate the pressure in the right atrium. Because the brachiocephalic and subclavian veins have no valves, the pressure wave created by the beating heart passes straight up into the vein, making these pulsations a fairly accurate guide to right atrial pressure. (TeachMeAnatomy: Venous Drainage of the Head and Neck.)

Kenhub gives the normal mean jugular venous pressure as 6 to 8 cm H2O (4.4 to 5.8 mmHg). A higher value is a classic sign of raised venous pressure. (Kenhub: Internal jugular vein.)

The internal jugular vein is a common route for a central venous catheter. The right vein is usually preferred because it has a larger diameter and gives a straighter path to the superior vena cava. In the landmark technique, the carotid pulse is felt near the lateral edge of the sternal head of sternocleidomastoid, and the vein usually lies superficial and slightly lateral to the artery, in the small triangle bounded by the two heads of sternocleidomastoid and the clavicle. (Merck Manual Professional: How To Do Internal Jugular Vein Cannulation (Landmark-Guided).)

The relationship is not fixed: Merck notes that variant orientations occur in 9 to 19% of patients, and lists arterial puncture, pneumothorax, haematoma, air embolism, catheter misplacement, infection and thrombosis among the complications. Ultrasound guidance increases the success rate and reduces complications. (Merck Manual Professional: How To Do Internal Jugular Vein Cannulation (Landmark-Guided).)

An ultrasound study of 78 patients found that with the head turned to the opposite side, the vein lay directly in front of the common carotid artery in 41.9% of sides, anterolateral in 33.8% and lateral in only 24.3%. Turning the head increased how much the vein overlapped the artery, and overlap became more likely with age, which matters because a needle passing through the vein can then reach the artery. (Umaña M et al. Variations in the anatomical relationship between the common carotid artery and the internal jugular vein: an ultrasonographic study. Colomb Med. 2015.)

The nearest named structures in the 3D model, measured from the centre of each part:

• Sternothyroid · muscular
• Sternohyoid · muscular
• Common carotid artery · cardiovascular
• Inferior thyroid artery · cardiovascular
• Thyrocervical trunk · cardiovascular
• First rib · skeletal
• Transverse cervical artery · cardiovascular
• Costocervical trunk · cardiovascular
• Superior intercostal artery · cardiovascular
• Scalenus anterior · muscular