Which cranial nerve innervates the muscles of facial expression?

The facial nerve, also known as cranial nerve VII, is responsible for the innervation of the muscles of facial expression. This nerve exits the brainstem and travels through the facial canal, branching out to provide motor control to a variety of facial muscles that contribute to expressions such as smiling, frowning, and blinking.

In addition to motor function, the facial nerve is also involved in transmitting taste sensations from the anterior two-thirds of the tongue and controlling some aspects of the autonomic nervous system, such as regulating salivary and lacrimal glands.

Understanding the specific role of cranial nerve VII is crucial for recognizing how facial expressions are produced and how dysfunctions in this nerve can lead to conditions like Bell's palsy, where there is weakness or paralysis on one side of the face. The other cranial nerves mentioned do not serve this purpose; they are involved in other functions such as vision, sensation, and various autonomic functions.