Critical Care Registered Nurse (CCRN) Practice Exam

How is the proper functioning of cranial nerves IX and X assessed?

1. By checking abdominal reflexes

2. By testing the gag reflex

3. By observing arm movements

4. By measuring balance ability

The correct answer is: By testing the gag reflex

The proper functioning of cranial nerves IX (glossopharyngeal nerve) and X (vagus nerve) is assessed primarily through the gag reflex. The gag reflex is a protective mechanism that involves both these nerves: the glossopharyngeal nerve is responsible for the sensory component, while the vagus nerve carries out the motor response. When the back of the throat is stimulated, it elicits the gag reflex, which serves as an important indicator of the integrity of these cranial nerves. Testing the gag reflex is essential in critical care settings as it helps evaluate the patient’s ability to protect their airway. A diminished or absent gag reflex can indicate neurological impairment, putting the patient at risk for aspiration and respiratory complications. The other options, while important in different contexts, do not directly assess the specific functions of cranial nerves IX and X. For instance, abdominal reflexes relate to spinal cord function, and observing arm movements pertains to upper extremity motor functions, while balance ability is associated with vestibular function.