All of the following cranial nerves carry parasympathetic fibers EXCEPT:

Explanation

## Parasympathetic Innervation via Cranial Nerves **Key Point:** Only four cranial nerves carry parasympathetic (craniosacral) fibers: CN III, CN VII, CN IX, and CN X. The accessory nerve (CN XI) is purely motor and carries no parasympathetic fibers. ### Parasympathetic Cranial Nerves — Mnemonic **Mnemonic:** **3-7-9-10** (or "Some Say Money Matters") - **CN III (Oculomotor):** Preganglionic fibers to ciliary ganglion → pupillary constriction, accommodation - **CN VII (Facial):** Preganglionic fibers to pterygopalatine and submandibular ganglia → lacrimal, salivary glands - **CN IX (Glossopharyngeal):** Preganglionic fibers to otic ganglion → parotid salivary gland - **CN X (Vagus):** Preganglionic fibers to thoracic and abdominal viscera → cardiac, GI, pulmonary parasympathetic control ### Why CN XI is Different | Feature | CN XI (Accessory) | Other Motor CNs | |---------|-------------------|------------------| | **Fiber type** | Somatic motor only | Motor ± parasympathetic | | **Innervation** | Sternocleidomastoid, trapezius | Muscles + autonomic targets | | **Ganglia association** | None | Parasympathetic ganglia | | **Autonomic role** | None | Parasympathetic control | **High-Yield:** CN XI is a **pure motor nerve** with no autonomic component. It innervates skeletal muscles of the neck and shoulder via the spinal accessory nucleus (C1–C5). **Clinical Pearl:** Lesions of CN XI present with ipsilateral shoulder shrug weakness and sternocleidomastoid atrophy—a purely motor deficit with no autonomic signs.