Sympathetic Innervation - Contains postganglionic sympathetic fibers - Cell bodies located in the superior cervical ganglion - Axons ascend with the internal carotid artery as a plexus of nerves - Sympathetic fibers supplying the eye separate from the carotid plexus within the cavernous sinus - Sympathetic fibers in the short ciliary nerves pass through the ciliary ganglion without forming synapses - Originate from neurons in the intermediolateral column of the thoracic spinal cord - Synapse in the superior cervical ganglion - Convergence ratio in the ganglion is approximately 100:1 - Controlled by supranuclear pathways descending through the brainstem and spinal cord - Interruption of the sympathetic chain produces pupillary constriction and eyelid droop - Innervate blood vessels, sweat glands, and 4 eye muscles - Dilator pupillae muscle dilates the pupil - Superior tarsal muscle elevates the upper eyelid - Inferior tarsal muscle and orbitalis muscle are vestigial in humans - Pupil size is controlled by both sympathetic and parasympathetic nerves

Sensory Innervation - Sensory fibers from the eyeball run through the short ciliary nerves - Pass through the ciliary ganglion without forming synapses - Join the nasociliary nerve and travel back through the ophthalmic nerve - Relay to specific nuclei in the thalamus and cerebral cortex - Distribution of sensory fibers is anatomically variable

Parasympathetic Innervation - Provides parasympathetic supply to the ciliary ganglion - Ciliary ganglion is a parasympathetic ganglion - Roughly twice as many incoming parasympathetic fibers as outgoing fibers - Presynaptic parasympathetic fibers originate in the Edinger-Westphal nucleus - Postsynaptic parasympathetic fibers leave the ciliary ganglion to supply the sphincter pupillae and ciliaris muscles.

Sympathetic Root - Contains postganglionic sympathetic fibers - Cell bodies located in the superior cervical ganglion - Axons ascend with the internal carotid artery as a plexus of nerves - Sympathetic fibers supplying the eye separate from the carotid plexus within the cavernous sinus - Sympathetic fibers in the short ciliary nerves pass through the ciliary ganglion without forming synapses - Originate from neurons in the intermediolateral column of the thoracic spinal cord - Synapse in the superior cervical ganglion - Convergence ratio in the ganglion is approximately 100:1 - Controlled by supranuclear pathways descending through the brainstem and spinal cord - Interruption of the sympathetic chain produces pupillary constriction and eyelid droop

Preganglionic Sympathetic Fibers - Originate from neurons in the intermediolateral column of the thoracic spinal cord - Synapse in the superior cervical ganglion - Convergence ratio in the ganglion is approximately 100:1 - Controlled by supranuclear pathways descending through the brainstem and spinal cord - Interruption of the sympathetic chain produces pupillary constriction and eyelid droop