The hypoglossal nucleus corresponds to which cranial nerve?

• A. CN X
• B. CN XII
• C. CN IX
• D. CN VI

Answer: (B)

The main idea here is that the hypoglossal nucleus is the motor nucleus for the twelfth cranial nerve, the hypoglossal nerve. Located in the medulla, it sends axons that form the hypoglossal nerve, which innervates all intrinsic and extrinsic tongue muscles. This connection explains why the hypoglossal nucleus corresponds to the twelfth cranial nerve and not to the others listed. The vagus and glossopharyngeal nerves involve different motor nuclei (like the nucleus ambiguus and the dorsal motor nucleus) and serve the pharynx, larynx, and other regions, while the abducens nerve has its own nucleus in the pons for controlling the lateral rectus muscle of the eye.