Bell's palsy is best described as which of the following?

• A. Acute facial nerve paralysis that is a lower motor neuron lesion of CN VII affecting the unilateral upper and lower face and is temporary, with most cases resolving between 3 weeks and 9 months.
• B. Central facial weakness due to an upper motor neuron lesion.
• C. Bilateral facial nerve palsy from a brainstem stroke.
• D. An autoimmune disorder affecting the trigeminal nerve.

Answer: (A)

Bell's palsy reflects an acute, idiopathic lower motor neuron injury to the facial nerve (CN VII) on one side, causing paralysis of all muscles on that half of the face, including the forehead. This pattern—weakness affecting both the upper and lower parts of the face on the same side—is what sets it apart from central (upper motor neuron) facial weakness, which tends to spare the forehead because the upper facial muscles receive bilateral cortical innervation. Bell's palsy is usually self-limited, with most people recovering over a period of weeks to several months. The other scenarios don’t fit because central lesions produce a different distribution of weakness (usually contralateral lower face with forehead spared), bilateral facial palsy suggests brainstem or systemic disease, and issues with the trigeminal nerve (CN V) affect different facial functions.