Critical Care Registered Nurse (CCRN) Practice Exam

Which cranial nerve is tested by having a patient repeat the phrase, "Round the rugged rock that ragged rascal ran"?

1. CN I

2. CN V

3. CN XII

4. CN IX

The correct answer is: CN XII

The correct answer is based on the role of cranial nerve XII, which is the hypoglossal nerve. This nerve is primarily responsible for the motor function of the tongue, facilitating movements necessary for speech and articulation. When a patient is asked to repeat a phrase like "Round the rugged rock that ragged rascal ran," they are utilizing their tongue in complex movements that involve coordination of speech sounds. This phrase specifically challenges the patient’s ability to manipulate tongue movements quickly and accurately, which is a direct function of the hypoglossal nerve. In testing cranial nerve XII, the clinician observes not only the articulation but also the strength and mobility of the tongue. Appropriate functioning of this nerve ensures the ability to perform precise speech tasks, making it essential for verbal communication. Other cranial nerves mentioned in the options, such as CN I (olfactory nerve), CN V (trigeminal nerve), and CN IX (glossopharyngeal nerve), have different primary functions. CN I is associated with the sense of smell, CN V is essential for facial sensation and mastication, and CN IX involves taste and gag reflex. None of these nerves are directly responsible for the articulation of speech in the same manner as cranial nerve XII.