Final answer:
The proper functioning of the facial nerve is often assessed by having the patient smile. The facial nerve controls the muscles of facial expression, and a smile requires the coordination and movement of these muscles.
Step-by-step explanation:
The proper functioning of the facial nerve is often assessed by having the patient smile. The facial nerve controls the muscles of facial expression, and a smile requires the coordination and movement of these muscles. If there is a problem with the facial nerve, the patient may not be able to smile on one side of their face or the smile may appear uneven.