NETTER - Neuroscience Flash Cards

Autonomic Distribution to the Eye
1. Short ciliary nerves
2. Ciliary ganglion
3. Oculomotor nerve (CN III)
4. Nucleus of Edinger-Westphal (CN III)
5. Pretectum
6. Superior cervical sympathetic trunk ganglion
7. Ophthalmic nerve
8. Long ciliary nerve
9. Optic nerve (CN II)
10. Gray ramus communicans
11. First thoracic sympathetic trunk ganglion
12. White ramus communicans
Comment: Smooth muscles controlling the aperture of the pupil
are innervated by sympathetic postganglionic noradrenergic fibers
(from the superior cervical ganglion to the pupillary dilator muscle)
and by parasympathetic postganglionic cholinergic fibers (from
the ciliary ganglion, supplied by CN III, to the pupillary constrictor
muscle). These sources keep the pupil in balance and responsive to
the ambient surroundings. Damage to CN III (e.g., from entrapment
against the tentorium cerebelli during transtentorial herniation)
results in a fixed, dilated pupil, unresponsive to light. Damage to the
sympathetic superior cervical ganglion or its central or preganglionic
supply results in a miotic pupil. The ciliary ganglion also supplies the
ciliary muscle, which, when contracted, lifts the zonular fibers of the
capsule of the lens upward and inward, permitting accommodation
for near vision (bunching of the lens for greater refraction of light).
Regional Neuroscience See book 9.45