Innervation of the corrugator supercilii muscle.

The frowning forehead is unwanted, generally because it gives an impression of anger and displeasure. The frown is formed mainly by the repeated contraction of the corrugator supercilii muscle. We studied the relevant nerve supply to the muscle in detail to enhance selective neurotomy. A bicoronal incision extending downward to the preauricle was made and the subgaleal dissection proceeded in 19 hemifaces of cadavers. The temporal branch of the facial nerve was divided into 2 to 4 smaller branches at the zygomatic arch. There were commonly 3 branches. The temporal branch is located 10 mm lateral to the supraorbital notch or foramen 2.8 to 25 mm above the supraorbital rim. It contains 4 to 7 thin rami (5 on average). A plexus mainly from the inferior ramus partly from the middle ramus of the temporal branch of the facial nerve enters the corrugator supercilii muscle in the supraorbital area. Because the temporal branch had multiple interconnection among its own rami, selective blocking of the middle ramus cannot promise the elimination of the frown line.