[Peripheral branches of the facial nerve in the cheek and chin area. Anatomy and clinical consequences].

The available descriptions of the innervation of the depressor anguli oris muscle and the peripheral distribution of the terminal branches of the marginal mandibular branch and buccal branches of the facial nerve are conflicting. Based upon dissections of 25 head halves we investigated the courses of the terminal branches of the marginal mandibular and buccal nerves. The marginal mandibular and buccal branches were found to form in the area of the mental foramen the mental and buccal plexus innervating the mimetic muscles by terminal nerve branches in the cheek area. The buccal plexus supplied the muscles of upper lip, cheek and nose. Furthermore, the depressor anguli oris muscle was also supplied by the buccal plexus. We also observed connections between marginal mandibular branch and mental nerve and between buccal branches of the facial nerve and buccal nerve of the trigeminal nerve. In case of injury to the marginal mandibular branch the depressor anguli oris muscle is not affected. Injury to the nerve branches of the depressor anguli oris muscle can be caused by operations or lesions in the area of the posterior border of this muscle.