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.