Measurement of the anatomic position of the corrugator supercilii.
OBJECTIVE: To standardize the location of the corrugator supercilii by using known facial landmarks. METHODS: The corrugator supercilii points of origin, insertion, and maximal muscle thickness were measured relative to the nasion and supraorbital notch in 21 cadavers. Comparisons of measurements between male and female cadavers were performed using a two-tailed t-test. RESULTS: The location of the corrugator supercilii was variable but was not significantly different between males and females. From the nasion, the mean point of origin was 4 mm lateral and 6 mm superior, the mean point of insertion was 33 mm lateral and 16 mm superior, and the mean maximal muscle thickness was 16 mm lateral and 10 mm superior. At their point of greatest thickness, most corrugators were found to lie below the upper border of the superciliary arch. CONCLUSIONS: There is variability in the location of the corrugator supercilii that is not gender dependent. When injecting botulinum toxin into the corrugator supercilii, it might be advantageous if the lower forehead skin of the brow is elevated, thus allowing for more precise injection. This may achieve weakness of the targeted muscle with lower doses of botulinum toxin, thus lessening the risk of eyelid and brow ptosis.