Common carotid artery its right side below is the brachiocephalic trunk, and above, the trachea, the inferior thyroid veins, and the remains of the thymus; to its left side are the left vagus and phrenic nerves, left pleura, and lung. The left subclavian artery is posterior and slightly lateral to it. The cervical portions of the common carotids resemble each other so closely that one description will apply to both. Each vessel passes obliquely upward, from behind the sternoclavicular joint to the level of the upper border of the thyroid cartilage, where it divides. At the lower neck the two common carotid arteries
Internal carotid plexus carotid plexus communicates with the trigeminal ganglion, the abducent nerve, and the pterygopalatine ganglion (also named sphenopalatine); it distributes filaments to the wall of the internal carotid artery, and also communicates with the tympanic branch of the glossopharyngeal nerve. Internal carotid plexus The internal carotid plexus (internal carotid plexus) is situated on the lateral side of the internal carotid artery, and in the plexus there occasionally exists a small gangliform swelling, the "carotid ganglion", on the under surface of the artery. Postganglionic sympathetic fibres ascend from the superior cervical ganglion, along the walls of the internal carotid artery, to enter