Sexual diagnosis of the glabellar region

Determination of sex is a key issue in skeletal identification. Morphological assessment has been one of the oldest approaches by which a particular structure can be evaluated visually. The purpose of this investigation is to evaluate morphological variation in the human glabellar region and its association with sexual dimorphism. The study sample is composed of 90 adult skulls with known sex, race (all Caucasoids), obtained from the Council of Forensic Medicine (Adli Tip Kurumu), Istanbul, Turkey. The glabellar region was cleared of soft tissue and photographs were taken at the closest focused distance to the specimens. The degree of smoothness-roughness of the glabella was classified into four prototypes from 0 (very smooth) to 3 (very rough). Each specimen without knowing its sex was judged as ideal, belonging to one of the prototypes by the senior author. Using the same prototypes, the photographs of the specimens were also rated by ten observers. The results indicated that none of the males were assigned to Prototype 0, and conversely, none of the females were classified as Prototype 3. The judges, however, ranked 8.2% of males as 0 and no females as 3. About 84% of males were in Prototype 2 or higher as judged by the senior author. Males were mostly in Prototype 1 or above, but females in 1 or below. There are various explanations as to why the human skull shows sexual dimorphism, however, the robust nature of the male is the obvious one. The smoothness of the supranasal region has not been associated with any specific well documented anatomic, functional, or sexual aspect of the skull. This study shows that there is an identifiable sexual dimorphism in the supranasal region, but its source has not been well known. It is expected that this results from both the muscles of facial expression and the masticatory function.