Final Answer:
The cranial nerve evaluated when a wisp of cotton is lightly brushed against the corner of the eye is D. CN V.
Step-by-step explanation:
D.Cranial Nerve V, also known as the trigeminal nerve, is responsible for the sensation in the face and control of the muscles involved in chewing. The specific branch of the trigeminal nerve involved in the light touch sensation on the face, including the corner of the eye, is the ophthalmic division (V₁). When a wisp of cotton is brushed against the corner of the eye, it activates sensory receptors in the skin, and the signal is transmitted through the ophthalmic division of the trigeminal nerve to the brain for interpretation.
The other cranial nerves mentioned are not primarily responsible for the sensation in this specific region. CN II (optic nerve) is associated with vision, CN III (oculomotor nerve) controls eye movements, and CN IV (trochlear nerve) also contributes to eye movement control. In contrast, CN V is the major sensory nerve for the face and plays a significant role in the corneal reflex, which involves a protective blink response to stimuli like a wisp of cotton touching the eye.
Understanding the functions of cranial nerves is essential for neurological assessments, helping clinicians identify potential issues with sensory or motor functions in specific areas of the head and face. In this scenario, the involvement of CN V underscores its importance in mediating sensory experiences in the facial region.