Carotid Plexus, Gross Anatomy

Description

Centered in the anterolateral neck, the carotid plexus forms a web of postganglionic sympathetic fibers that invests the common carotid artery and then tracks superiorly along the internal and external carotid arteries. Fine yellow nerve filaments hug the arterial adventitia medial to the sternocleidomastoid region, with the plexus extending toward the skull base where it relates to the carotid canal and adjacent cranial nerve pathways. Inferiorly, the fibers are continuous with the cervical sympathetic trunk and the superior cervical ganglion, positioned posterior to the carotid sheath contents. Bone landmarks from the skull, mandible, clavicle, and upper cervical vertebrae anchor the relationships in three dimensions. Clinically, this is the pathway that carries sympathetic supply to the dilator pupillae and superior tarsal muscle, so disruption along the internal carotid plexus helps explain postganglionic Horner syndrome after internal carotid artery dissection or carotid endarterectomy. Pain referral in carotidynia and certain headache syndromes also gets taught against this anatomy because perivascular sympathetic fibers track with the arterial wall. Small fibers, big consequences. For teaching, the model works well in gross anatomy and head and neck neuroanatomy blocks when you need students to connect the superior cervical ganglion to perivascular autonomic plexuses rather than treating the sympathetic chain as an isolated cord. It also fits surgical atlases and patient education materials discussing carotid sheath exposure, carotid endarterectomy, and neck dissection where iatrogenic autonomic deficits are a real risk. Anatomical accuracy verified by SciePro's Medical Advisory Board.