The carotid sheath contains a few different structures. It contains the common carotid artery, the vagus nerve, the internal jugular vein, parts of the external and internal carotid arteries, the vagus nerve, portions of other nerves, and cervical lymph nodes. The common carotid and its external and internal branches supply the head and neck with oxygenated blood. When this blood needs to return from the brain to the heart, it is collected by the internal jugular vein that also runs through the carotid sheath. It is a branch of the jugular vein which splits up into the aforementioned internal and external jugular veins. The blood from the jugular veins is transported to the superior vena cava that carries the blood back to the heart.