What is the first branch given off by the facial nerve?

The first branch given off by the facial nerve, also known as cranial nerve VII, is the posterior auricular nerve. This nerve branches directly from the facial nerve as it exits the skull through the stylomastoid foramen.

The posterior auricular nerve provides motor innervation to the muscles behind the ear, including the occipitalis muscle, and it plays a role in the movement of the auricle of the ear. Understanding the anatomy of the facial nerve and its branches is vital for surgical procedures in the region, as well as for diagnosing facial nerve pathology.

The other branches mentioned, such as the nerve to stapedius, chorda tympani, and greater petrosal nerve, arise further along the course of the facial nerve, after the posterior auricular nerve has already been given off. Each of these branches has specific functions; for instance, the nerve to stapedius innervates the stapedius muscle in the middle ear, chorda tympani carries taste fibers from the anterior two-thirds of the tongue, and the greater petrosal nerve is involved in parasympathetic functions, including salivation by innervating the lacrimal and salivary glands.