Which of the following cranial nerves carries parasympathetic preganglionic fibres to the ciliary ganglion?

Explanation

## Parasympathetic Innervation of the Eye **Key Point:** The oculomotor nerve (CN III) carries parasympathetic preganglionic fibres that synapse in the ciliary ganglion to control pupillary constriction (miosis) and accommodation. ### Parasympathetic Pathway to the Eye ```mermaid flowchart TD A[Edinger-Westphal nucleus<br/>Midbrain]:::outcome --> B[Preganglionic parasympathetic fibres<br/>in CN III]:::action B --> C[Ciliary ganglion<br/>Orbit]:::outcome C --> D[Postganglionic fibres<br/>via short ciliary nerves]:::action D --> E[Sphincter pupillae<br/>Ciliary muscle]:::outcome E --> F[Miosis + Accommodation]:::action ``` ### CN III Parasympathetic Components | Component | Origin | Target | Function | | --- | --- | --- | --- | | **Preganglionic parasympathetic** | Edinger-Westphal nucleus (midbrain) | Ciliary ganglion | Pupil constriction, accommodation | | **Somatic motor** | Oculomotor nucleus (midbrain) | Superior/inferior rectus, medial rectus, inferior oblique, levator palpebrae | Eye movements, lid elevation | **High-Yield:** The Edinger-Westphal nucleus is the parasympathetic nucleus of CN III and is a classic NEET PG topic. Damage to CN III results in a "down and out" eye with a dilated pupil (mydriasis) due to unopposed sympathetic activity. **Mnemonic:** **ACCOMM** = **A**ccommodation and **C**onstriction of pupil are **O**culomotor (CN III) **M**ediated **M**echanism.