ABSTRACT
BACKGROUND: Elimination of glabellar frown lines by direct denervation of the corrugator and procerus muscles has proven elusive. Furrows often persist after the frontal branch of the facial nerve has been divided. In order to find an explanation for these observations and to provide an anatomic basis for future surgical strategies, the pattern of innervation of these muscles was studied. METHODS: Two separate investigations were performed: (1) cadaveric anatomical dissection in 18 fresh cadaver hemi-faces utilizing loupe magnification, operating microscope, and template tracings; and (2) electrophysiologic testing performed in 12 healthy volunteers utilizing a Viking Ile nerve stimulator (Nicolet, Madison, WI). RESULTS: The corrugator was found to have a dual nerve supply with contributions from branches of the frontal, zygomatic and buccal branches of the facial nerve. The frontal branch passes deep to the orbicularis at the level of the eyebrow; and the buccal branch, after receiving a contribution from the zygomatic, forms the angular nerve, which then passes superiorly in front of the medial canthus to supply both corrugator and procerus. The procerus muscle was found to receive contributions from the angular nerve exclusively. CONCLUSIONS: Procedures designed to denervate the corrugator should be directed at both components of its redundant nerve supply, the frontal branch as well as the angular nerve. Division of the angular nerve will also denervate the procerus muscle. Both frontal nerve branches and angular nerve components are accessible through an upper blepharoplasty incision.
