If a person has normal musculature but has difficulty swallowing, which nerves should be tested for function?: (A) Hypoglossal and phrenic, (B) Hypoglossal and splanchnic, (C) Glossopharyngeal and vagus, (D) Splanchnic and vagus
Answer is D. The upper 2/3 of the esophagus contains striated muscle. It is derived from the pharyngeal arches and innervated by the vagus nerve (CN X). The lower 1/3 contains smooth muscleft from splanchnic mesoderm and is innervated by the splanchnic plexus.