Which cranial nerve is involved in facial expression?

The cranial nerve that is primarily responsible for facial expression is the facial nerve. This nerve innervates the muscles of facial expression, allowing for various movements such as smiling, frowning, and raising eyebrows. It emerges from the brainstem and travels through the facial canal, branching out to enhance facial movements and sensations.

In addition to its motor functions related to facial muscles, the facial nerve also carries sensory afferents for taste from the anterior two-thirds of the tongue and provides parasympathetic innervation to several glands, including salivary and lacrimal glands. The involvement of the facial nerve in both motor and sensory functions underscores its essential role in facial dynamics and expressions.