Corpus: Internal jugular vein

The internal jugular vein is a major vein located in the head and neck region. It is the continuation of the sigmoid sinus and exits the cranial cavity through the posterior section of the jugular foramen.

The internal jugular vein runs alongside the internal carotid artery and the vagus nerve, traveling from a dorsal to ventrolateral position as it descends towards the venous angle (angulus venosus) behind the sternoclavicular joint. At this point, it joins with the subclavian vein on its respective side to form the brachiocephalic vein.

Medially, the vein lies adjacent to the styloid process and travels in a medial-caudal direction. It is covered by the parotid gland and the sternocleidomastoid muscle. As it progresses, it is crossed by the posterior belly of the digastric muscle near the floor of the mouth and by the superior belly of the omohyoid muscle in the neck.

The internal jugular vein has two notable dilations along its course:

• Superior bulb of internal jugular vein: This dilation occurs at the beginning of the vein, just after it exits the jugular foramen.
• Inferior bulb of internal jugular vein: This dilation is found just behind the sternoclavicular joint.

The internal jugular vein collects venous blood from the brain, skull, face, and neck, corresponding to the areas supplied by the common carotid artery. Major veins draining into the internal jugular vein include:

• Inferior petrosal sinus
• Facial vein (in the carotid triangle, serving as the main collecting vein of the facial area)
• Pharyngeal veins (from the pharyngeal venous plexus)
• External jugular vein (occasionally)
• Meningeal veins
• Lingual vein
• Superior thyroid vein
• Middle thyroid vein (occasionally)
• Sternocleidomastoid vein

The internal jugular vein is commonly accessed in intensive care medicine for the insertion of a central venous catheter (CVC). This procedure is performed to monitor central venous pressure, administer medications, or deliver fluids directly into the central circulation. The internal jugular vein is often chosen for its relatively straight course to the superior vena cava and its consistent anatomical location, making it a reliable site for CVC placement.

• 3D model brachial plexus - anatomical situs; Dr Claudia Krebs (Faculty Lead) University of British Columbia