Determining Chin Dimensions for Feminizing Genioplasty: An Anatomic Study.

[BACKGROUND] Feminizing genioplasty warrants chin modification to achieve feminine characteristics. This study compared female and male facial skeletal dimensions and shape to guide feminizing genioplasty.

[METHODS] Skulls stored at the Cleveland Museum of Natural History were analyzed. Sex, age, and race were documented. Heights and widths of the face and chin were measured, normalized, and compared.

[RESULTS] Forty-three male (43.58±12.52-y-old) and 43 female (40.48±12.04-y-old) skulls were included. Within each group, 25 skulls were of African American (AA) origin and 18 were of Caucasian (C) origin. Absolute chin heights were larger in AA and C males compared with females ( P <0.05). After normalization to lower facial height, there was a trend toward greater chin height in AA males compared with females ( P =0.07). Parasagittal chin width in AA males was significantly larger than AA females ( P =0.0006). Interforaminal chin width in C males trended toward being significantly larger than females ( P =0.08). Following normalization of chin widths, no significant sex-based differences were noted for AA skulls except for the interforaminal/intergonial ratio, which was smaller in AA males ( P =0.04). For C skulls, most normalized ratios were significantly smaller in males ( P <0.05). C females had wider angles at the point of maximum chin projection ( P =0.007) and wider symphyseal inclinations ( P <0.0001). These differences were not present in AA skulls ( P >0.05). Regardless of race, male chins appeared square, whereas female chins were round.

[CONCLUSIONS] While chin width reduction is not needed for most patients, height reduction could be considered. Chin contouring is the most central component of feminizing genioplasty.