The internal jugular vein is a major blood vessel located in the neck. It is responsible for draining blood from the brain, face, and neck, returning it to the heart. This vein runs alongside the carotid artery, which supplies blood to the brain, and is crucial for maintaining proper blood circulation. The internal jugular vein begins at the base of the skull and travels down the neck, eventually merging with the subclavian vein to form the brachiocephalic vein. It is often used in medical procedures, such as central venous catheterization, due to its accessibility and size.