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superior cervical ganglion (largest) – adjacent to C2 & C3; postganglionic axon projects to target: (heart, head, neck) via "hitchhiking" on the carotid arteries
Nerves emerging from cervical sympathetic ganglia contribute to the cardiac plexus, among other things.
Unlike all other ganglia, the medial branches of the cervical ganglia are 95% postganglionic axons.
Additional images
Muscles, arteries and nerves of neck. Newborn dissection.