The advanced practice registered nurse (APRN) suspects a trigeminal nerve (cranial nerve V) injury in a patient presenting with difficulty chewing. What tool will the APRN choose to complete the assessment?

A. Flashlight is incorrect because it is primarily used to assess pupillary reactions (cranial nerves II and III) or to inspect the oral cavity. While a flashlight helps with visual inspection and pupil response testing, it does not evaluate the sensory or motor functions of the trigeminal nerve, which are essential for diagnosing its injury. B. Cotton swab is correct because the trigeminal nerve has both sensory and motor components. The sensory function is responsible for facial sensation across three divisions: ophthalmic, maxillary, and mandibular. The APRN uses a cotton swab to lightly touch different regions of the face, including the forehead, cheeks, and jawline, to assess the patient’s ability to feel light touch. The motor function controls the muscles of mastication, which are essential for chewing. The APRN can assess this by asking the patient to clench their teeth, move the jaw from side to side, or resist jaw opening. Using both observations helps identify trigeminal nerve injury, which may manifest as loss of facial sensation, weakness in jaw movement, or difficulty chewing. C. Snellen chart is incorrect because it is used to assess visual acuity, which evaluates cranial nerve II (optic nerve). It provides no information about facial sensation or the ability to chew, so it is not appropriate for trigeminal nerve assessment. D. Tuning fork is incorrect because it is used to assess hearing (cranial nerve VIII) or vibratory sensation in peripheral nerves. While useful in other neurological assessments, it does not provide data on trigeminal nerve function, either sensory or motor.