To the Editor.
—The anatomy of the facial nerve within the various facial muscles that they innervate is quite important yet is seldom mentioned in the literature. Surgeons who perform eyelid or brow surgery should be concerned with the location of those fibers from the temporal and zygomatic branches that innervate the orbicularis oculi muscles.' Interruption of these nerves prior to entry into the orbicularis or within the distribution of the orbicularis may, at least temporarily, prevent full closure of the eyelids, resulting in possible corneal damage.The facial nerve exists from the styloid canal in the mastoid process of the temporal bone, and then passes beneath the external auditory canal to enter the posterior substance of the parotid gland.2,3 Here it divides into an upper (temporofacial) and lower (cervicofacial) branch. The upper branch further divides into temporal and zygomatic branches; the lower branch divides into buccal, mandibular, and
Jordan DR, Anderson RL. The Facial Nerve in Eyelid Surgery. Arch Ophthalmol. 1989;107(8):1114-1115. doi:10.1001/archopht.1989.01070020180007