What equipment would be necessary to complete an evaluation of cranial nerves 9 and 10 during a physical assessment?
A. A cotton ball
B. A penlight
C. An ophthalmoscope
D. A tongue depressor and flashlight
Correct Answer: D. A tongue depressor and flashlight
Cranial nerves 9 and 10 are the glossopharyngeal and vagus nerves. The gag reflex would be evaluated. The 9th (glossopharyngeal) and 10th (vagus) cranial nerves are usually evaluated together. Whether the palate elevates symmetrically when the patient says “ah” is noted. If one side is paretic, the uvula is lifted away from the paretic side. A tongue blade can be used to touch one side of the posterior pharynx, then the other, and symmetry of the gag reflex is observed; bilateral absence of the gag reflex is common among healthy people and may not be significant.
Option A: For the 5th (trigeminal) nerve, the 3 sensory divisions (ophthalmic, maxillary, mandibular) are evaluated by using a pinprick to test facial sensation and by brushing a wisp of cotton against the lower or lateral cornea to evaluate the corneal reflex. If facial sensation is lost, the angle of the jaw should be examined; sparing of this area (innervated by spinal root C2) suggests a trigeminal deficit. A weak blink due to facial weakness (eg, 7th cranial nerve paralysis) should be distinguished from depressed or absent corneal sensation, which is common in contact lens wearers. A patient with facial weakness feels the cotton wisp normally on both sides, even though blink is decreased.
Option B: A penlight provides a source of light and has become the most common used tool to assess pupil diameter. Asymmetry of pupil constriction in response to light means one pupil constricts and the other remains dilated or constricts more slowly. It may indicate dynamic anisocoria or a Marcus Gunn pupil, a relative afferent pupillary defect (RAPD), or temporal lobe herniation in the brain.
Option C: The eye can be examined with routine equipment, including a standard ophthalmoscope; thorough examination requires special equipment and evaluation by an ophthalmologist. Ophthalmoscopy (examination of the posterior segment of the eye) can be done directly by using a handheld ophthalmoscope or with a handheld lens in conjunction with the slit lamp biomicroscope.