What does the Glossopharyngeal Nerve (CN IX) innervate to assist in swallowing?

The Glossopharyngeal Nerve (CN IX) plays a crucial role in the process of swallowing by innervating the stylopharyngeus muscle. This muscle is located in the pharynx and functions to elevate the pharynx and larynx during swallowing, which assists in the passage of food through the esophagus and prevents aspiration. Additionally, the stylopharyngeus muscle helps to widen the pharynx, facilitating the movement of the bolus of food.

The other options refer to muscles innervated by different cranial nerves. For instance, the mylohyoid muscle is primarily innervated by the mylohyoid branch of the inferior alveolar nerve (a branch of the mandibular nerve, CN V3). The masseter muscle is also innervated by the mandibular division of the trigeminal nerve (CN V). Lastly, the tensor veli palatini muscle is innervated by the mandibular branch of the trigeminal nerve (CN V) as well. Thus, the correct choice highlighting the role of the stylopharyngeus muscle is pivotal for understanding the specific contributions of CN IX to swallowing.