The chorda tympani nerve, a branch of the facial nerve, carries preganglionic parasympathetic fibers to which ganglion?

Explanation

## Chorda Tympani: Course and Parasympathetic Innervation **Key Point:** The chorda tympani is a branch of the facial nerve (CN VII) that carries preganglionic parasympathetic fibers to the submandibular ganglion. Postganglionic fibers then innervate the submandibular and sublingual salivary glands. ### CN VII Parasympathetic Pathway ```mermaid flowchart TD A[Facial Nerve CN VII]:::outcome --> B[Chorda Tympani]:::action B --> C[Preganglionic parasympathetic fibers]:::action C --> D[Submandibular Ganglion]:::outcome D --> E[Postganglionic fibers]:::action E --> F[Submandibular gland]:::outcome E --> G[Sublingual gland]:::outcome ``` ### CN VII Branches and Their Parasympathetic Targets | Branch | Preganglionic Fibers to | Postganglionic Innervates | | --- | --- | --- | | Chorda tympani | Submandibular ganglion | Submandibular & sublingual glands | | Greater petrosal nerve | Pterygopalatine ganglion | Lacrimal gland & palatal glands | | Nerve to stapedius | — | Stapedius (motor, not parasympathetic) | | Nerve to posterior belly of digastric | — | Posterior belly of digastric (motor) | **High-Yield:** The chorda tympani has a distinctive course: it arises from CN VII within the temporal bone, crosses the tympanic membrane (hence the name), and exits the skull to join the lingual nerve (a branch of CN V₃) before reaching the submandibular ganglion. **Clinical Pearl:** Damage to the chorda tympani (e.g., in middle ear surgery or Bell's palsy) results in loss of taste to the anterior 2/3 of the tongue on the affected side AND decreased salivation from the submandibular and sublingual glands.