Question

A 26-year-old male presents with facial weakness which started two days ago. He also reports that he can't taste food very well. As part of your cranial nerve assessment, you ask the patient to smile, with the result shown below. Which cranial nerve is affected?

Option 1: Facial nerve (CN VII)
Option 2: Trigeminal nerve (CN V)
Option 3: Vestibulocochlear nerve (CN VIII)
Option 4: Olfactory nerve (CN I)

Answer 1

Facial weakness and diminished taste in a patient suggests impairment of the facial nerve (CN VII), which is responsible for controlling muscles of facial expression and taste sensation from the anterior tongue.

Step-by-step explanation:

A 26-year-old male presents with facial weakness and reduced taste sensation. Such symptoms are indicative of a cranial nerve issue. Facial weakness during expression (like smiling) and altered taste primarily implicate the facial nerve (CN VII). The facial nerve is responsible for controlling muscles of facial expression, conveying taste sensation from the anterior two-thirds of the tongue, and providing motor innervation for some salivary glands.

Motility impairment in smiling and facial asymmetry during expression are hallmark signs of a facial nerve deficit. Taste disturbances further support this, as the facial nerve carries taste sensations. The other cranial nerves mentioned, such as the trigeminal nerve (CN V), the vestibulocochlear nerve (CN VIII), and the olfactory nerve (CN I), are related to other sensory and motor functions that do not match the presentation of facial weakness and taste issues.