Introduction
In identification of sex, sacral bones are of greatest interest to the forensic experts and anthropologists.1 The morphometric parameters of sacrum varies in different populations leads to variations in sacral index.2, 3 The sacral length, sacral breadth, curved length of sacrum, first sacral vertebral dimensions, ala of sacrum length play a greater role in sex determination. The sacral index is one of the best parameter in identify the sex.3 The sacral index plays a significant role as sex determining parameter among populations observed in previous literature.4, 5 Our study aimed to analyze the sacral index and its significance in sex determination.
Materials and Methods
A total of 42 dry adult human sacral bones of known sex (19 – female sacra; 23- male sacra) collected from Anatomy Department, Santhiram Medical College, Nandyal to measure the sacral index and its significance. The length and breadth of male and female sacra were measured separately using vernier calipers. The sacral length measured from the promontory to the middle of antero-inferior margin of last sacral vertebra (Figure 1). The sacral breadth measured from the lateral most points of ale of sacrum (Figure 2). The parametric values were statistically analyzed.
The sacral index (SI) is calculated by the following formula
Sacral Index (SI) = Sacral Breadth X 100
Sacral Length
Figure 1
The length (A-B) of the sacrum measured from the midline from antero-superior margin of the promontory to the middle of antero-inferior margin of last sacral vertebra
Table 1
Distribution of adult sacra and their sacral index
Results
The sacral bones are collected and categorized based on their sex and considered for the current study (Figure 3). We noted the mean sacral length in male sacra was 96.739+1.912, and mean sacral breadth was 96.521+1.805. The mean sacral length in female sacra was 95.894+2.643 and mean sacral breadth was 99.842+3.287 in the present study (Table 1). We noted the mean sacral index 101.142+2.148 in male sacra, and 103.668+2.271 in female sacra with significantly higher sacral index in female sacra than male sacra in this study (Table 2)
Discussion
The female sacral length is lower than length of male sacra.6, 7 Greater length may be due to the incidence of six piece sacrum in male sacra.4 The sacral index and mean breadth were significantly higher in female sacra compared with male sacra in the present study. The results are in agreement with previous literature.8, 9, 10 In determination of sex, the veracity of sacral index is 95% and also there is a variation of sacral index populations due to difference in morphometric parameters of the sacra.5 In this study, the sacral index of male and female are 101.1, 103.6 classified under medium sacra category (Hyplatycheiric category - Sacral Index from 100 to 105.9) according to previous literature.10 Sacral index in male sacra is much higher compared to Telangana Region and Punjab Region studies on sacral index.11, 12 The female sacral index is much higher compared to Madhya Pradesh Region and Varanasi Region studies.13, 14 The sacral index was higher in female sacra in Whites and Blacks (White males-106.49, Black males -106.17; white females- 108.69, Black females - 112.35) The lower sacral index in males compared to sacral index in females affirms that sacral index varies in divergent populations.13, 14, 15, 16
Article
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