OBJECTIVETo study the course and distribution of buccal and marginal mandibular branches of facial nerve, and its relevance to the treatment of facial paralysis and the protection of facial nerve during surgery.

METHODS12 cadaver heads were dissected (24 specimens). The course of the buccal and marginal mandibular branch and the interconnections between them were observed. The relationship of buccal branch to parotid duct, marginal mandibular branch to the inferior border of mandible were studied. With modified Sihler's staining technique, the distribution of facial nerve branches in innervated mimetic muscles was displayed. These anatomic relationships mentioned above were further confirmed during the operation of 40 patients with facial paralysis.

RESULTSParotid duct had a constant surface landmark. Buccal branch mainly consisted of 2-3 ramifications in 87.5% of the specimens, while marginal mandibular branch was double or single in 95.9% of the specimens. The buccal branch coursed within the distance between 10.7 mm above and 9.3 mm below the parotid duct, and innervated mimetic muscles of midface. The marginal mandibular branch coursed within the distance between 13.4 mm above and 4.8 mm below the lower border of mandible, crossed superiorly the facial artery and innervated mimetic muscles of lower lip.

CONCLUSIONSThere is a close relationship of buccal branch to parotid duct and marginal mandibular branch to facial artery and lower border of mandible. With modified Sihler's staining technique, the original 3-dimensional picture of the intramuscular nerve distribution in human mimetic muscles.