A revised nose tip shape validation method for facial reconstruction based on CT data from a modern German population.

Several methods aid with reconstructing features of the human nose, including angle, projection and width, but only one study by Davy-Jow et al. (2012) has focused on nose tip shape. The main finding was that the shape of the nasal bridge is consistent with the shape of the nose tip. The study also theorised that the method would not be suitable for snub (upturned) noses. Although promising, further investigation with a larger sample of different origin would be of benefit. In addition, grouping samples into upturned, horizontal and downturned nose tips could reveal the need for a difference in the applied method. The approach has been recreated with a larger sample size (N = 103 versus N = 25) derived from a modern German population. Based on soft tissue models, the individuals were firstly grouped into three categories; upturned, horizontal, and downturned noses. Computed Tomography (CT) data allowed the simultaneous visualisation of both skull and (semi-transparent) facial surfaces. Each head was viewed frontally in the Frankfurt Horizontal Plane (FHP), and then tilted back until the nasal tip superimposed the nasal bridge, with the angle of tilt measured from the FHP. The results show that the angle of tilt is significantly different for upturned, horizontal, and downturned noses, but that it can be equally applied to all three groups. The mean angle was 44° for upturned noses, 51° for horizontal, and 56° for downturned. Error studies suggest a very high accuracy and repeatability with intra-class correlation coefficients of 0.991 (inter-observer error) and 0.972 (intra-observer error) respectively.

Dilemma of Gonial Angle in Sex Determination: Sexually Dimorphic or Not?

BACKGROUND AND AIM: The determination of sex from human remains has a crucial role in forensic anthropology. It has been known that the mandible has several useful traits for sex determination. The gonial angle, which is one of them, has been evaluated by forensic practitioners to identify sexual dimorphism with morphologic and metrical analyses. However, there are opposing approaches on the sexual dimorphism of the gonial angle in the literature, which contradict each other. There are also some other studies asserting that it cannot be employed in sex determination. The purpose of this study is first to figure out the reason for this dilemma and then establish the significance of the gonial angle in sex determination in a white sample. METHODS: Computed tomography scans were obtained from 300 adults (150 males and 150 females), which were divided into 3 age groups (20-39, 40-59, 60-80 years). The gonial angle, which is formed by 2 lines: (1) between the most posterior point of the mandibular condyle and the gonion and (2) between the most inferior point of the mandibular symphysis and gonion, was measured on computed tomography scans. In order to observe differences among the 3 age groups, the collected data were analyzed using 1-way analysis of variance followed by a least significant difference post hoc test. Two-way analysis of variance was used to compare sex differences in each age group. DISCUSSION: It is suggested that the probable reason of this dilemma is the unsubtle samples of the researches. Categorizing the sample into age groups with statistically sufficient number makes the data more valuable in terms of examining the differences related to sexual dimorphism. This study also reported that males showed slightly smaller gonial angle values than those of females in all age groups. No statistically significant difference was observed in the gonial anthropometric values for middle age groups (20-39 and 40-59 years), whereas it shows statistically sexual dimorphism for senior adult group (60-80 years). However, the results revealed that the gonial angle is not a particularly good indicator to identify the sex from the cranium and should not be used as a sole criterion.