Anatomical study of the corrugator supercilii muscle and its clinical implication with botulinum toxin A injection

Purpose Botulinum toxin A (BTX-A) injection targeting the corrugator supercilii muscle (CSM) has been widely performed to remove glabellar wrinkles. The aim of the present study was to elucidate the exact location and dimensions of the CSM in Koreans by elaborate dissections followed by accurate measurements to provide the topographic guidance for an efficient and safe manipulation of the BTX-A injection. Methods Thirty-five specimens from twenty fixed Korean cadavers (twelve males, eight females; mean age, 65.5 years) were examined in the present study. Results The CSM comprised oblique and transverse bellies, with the oblique belly being classified into narrow vertical (62.9 %) and broad triangular (37.1 %) types. The widths at the apex and base of the CSM were 10.0 ± 3.7 and 19.5 ± 5.4 mm (mean ± SD), respectively. The mostmedial apical point was located 17.3 ± 3.2 mm superior to the horizontal intercanthal plane (HL) and 4.3 ± 1.9 mm lateral to the vertical midline of the face (VL). The mostlateral apical point was located 15.8 ± 2.4 mm superior to the HL and 13.9 ± 4.3 mm lateral to the VL. The mostmedial basal point was located 31.2 ± 3.2 mm superior to the HL and 16.4 ± 4.8 mm lateral to the VL. The mostlateral basal point was located 28.6 ± 4.9 mm superior to the HL and 35.3 ± 4.3 mm lateral to the VL. Conclusion The topographic data on the CSM presented here in will be helpful for the accurate and safe implementation of BTX-A injection to the forehead in Koreans.