A nurse is performing a neurological assessment for a client who has head trauma. Which of the following assessments will give the nurse information about the function of the oculomotor cranial nerve?

Choice A reason: Having the client touch their nose with eyes closed tests cerebellar function and proprioception, not the oculomotor nerve (cranial nerve III). This assesses coordination and sensory integration, unrelated to the nerve controlling eye movement and pupil response, making it an incorrect choice. Choice B reason: Instructing the client to look up and down without moving their head tests the oculomotor nerve (cranial nerve III), which innervates most extraocular muscles and controls pupil constriction. This movement relies on nerve function for vertical eye motion, making it the correct assessment for oculomotor nerve integrity. Choice C reason: Shrugging shoulders against resistance tests the spinal accessory nerve (cranial nerve XI), which innervates the trapezius muscle. This is unrelated to the oculomotor nerve, which governs eye movement and pupil response, so this action does not assess cranial nerve III function. Choice D reason: Observing smiling and frowning tests the facial nerve (cranial nerve VII), which controls facial muscles. This is distinct from the oculomotor nerve, which manages eye movements and pupil constriction, making it an inappropriate method for assessing cranial nerve III function.