The ischiopubic index was studied in adult pelvic X-ray films of subjects aged eighteen to seventy years. A total of 120 X-ray films made of 60 males and 60 females were collected from LUTH, Lagos State. The ischiopubic index was calculated by dividing the pubic length by ischial length and by multiplying by 100. The mean ischiopubic index for males was 101.05 ± 16.65 and that of the females was 115.99 ± 18.5. Sex differences of these indices were statistically significant (
The innominate bone has long been recognised as one of the best skeletal indicators of sex in an adult individual. Methods have been developed which provide criteria for sex determination of adults using features of the innominate bone [
lbone of females was much longer than those of the males. This has been confirmed in adult black Malawians [
The results obtained will contribute to comparative data base for Nigerians [
A total of 120 radiographs of the anterior-posterior view of the pelvis were collected comprising 60 males and 60 females. All the radiographs were collected from the University of Lagos Teaching Hospital (LUTH), Lagos State, Nigeria. Only normal adult radiographs of subjects aged between 18 and 70 years were used.
Materials included the X-ray illuminator, the radiographic films, a pencil, and transparent metric rule.
The technique used for measuring the ischiopubic index was described by Washburn [
The radiograph of pelvis showing the measurements of the ischial length AC and pubic length AB (Ekanem et al. [
The data obtained from the measured parameters were analyzed statistically using one-way analysis of variance (ANOVA). The Student’s
The actual range of the index for the male and female sexes was found out and the values were used in sex determination. The identification points were taken from the actual range for both sexes. The parameters were then subjected to demarking points (DPs) analysis as evolved by Jit and Singh [
The values of the data obtained from the X-ray measurements of the pubic and ischial lengths of the hip bone and their ischiopubic indices for the 120 radiographs are shown in Tables
Measurement in mm of pubic length, ischial length, and ischiopubic index in males in Lagos State.
Measurement and calculations | Pubic length | Ischial length | Ischiopubic index |
---|---|---|---|
Number | 60 | 60 | 60 |
Mean | 68.7* | 68.93* | 101.05* |
Standard deviation | ±9.62 | ±10.77 | ±16.65 |
Actual range | 43–85 | 50–90 | 75–133.33 |
Identification point | <58 | >90.00 | <92.05 |
Percentage identification point | 10% | 0% | 23.33% |
Calculated range | 59.11–78.35 | 58.16–79.7 | 84.4–117.7 |
Demarking point | <68.12 | >75.44 | <97.49 |
Percentage demarking point | 43.33% | 26.67% | 46.67 |
Measurement in mm of pubic length, ischial length, and ischiopubic index in females in Lagos State.
Measurement and calculations | Pubic length | Ischial length | Ischiopubic index |
---|---|---|---|
Number | 60 | 60 | 60 |
Mean | 76.6* | 66.97* | 11.5.99* |
Standard deviation | ±8.48 | ±8.47 | ±18.5 |
Actual range | 58–91 | 55–90 | 92.05–163.63 |
Identification point | >85 | <50 | >133.33 |
Percentage identification point | 16.67% | 0% | 13.33% |
Calculated range | 68.12–85.08 | 58.5–75.44 | 97.49–134.49 |
Demarking point | >78.35 | <58.16 | <117.7 |
Percentage demarking point | 43.33% | 13.33% | 50% |
Comparative analysis of pubic length, ischial length, and ischopubic index in different races.
Racial group source | Pubic length | Ischial length | Ischiopubic index | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Male | Female | Male | Female | Male | Female | |||||||
Number | Mean | Number | Mean | Number | Mean | Number | Mean | Number | Mean | Number | Mean | |
Eskimos [ |
129 | 74.1 | 95 | 80.1 | 129 | 88.4 | 95 | 81.0 | 129 | 83.9 | 95 | 98.8 |
American Whites [ |
100 | 73.8 | 100 | 77.9 | 100 | 88.4 | 100 | 78.3 | 100 | 83.6 | 100 | 99.5 |
American Negros [ |
50 | 69.2 | 50 | 73.5 | 50 | 86.6 | 50 | 77.5 | 50 | 79.9 | 50 | 95.0 |
Bantus [ |
82 | 66.2 | 70 | 73.2 | 82 | 80.3 | 70 | 74.8 | 82 | 82.5 | 70 | 78.1 |
Australian Aborigines [ |
89 | 63.3 | 72 | 69.2 | 89 | 81.2 | 72 | 74.7 | 89 | 76.0 | 72 | 92.7 |
Nigerians [ |
114 | 65.8 | 100 | 75.6 | 114 | 70.1 | 100 | 64.5 | 114 | 94.2 | 100 | 117.3 |
Nigerians (present study) | 60 | 68.7 | 60 | 76.6 | 60 | 68.93 | 60 | 66.97 | 60 | 101.05 | 60 | 115.99 |
The pubic length of females was noticed to be more than that of the males. In Tables
The demarking point as seen in Tables
The ischial length of males was higher than that of the females. The ischial length of the female hipbone varied from 55 mm to 99 mm with a mean value of
The ischiopubic index of the male hipbone as seen in Table
As seen in Tables
The distinctive morphology of the human bone (innominate) and its clear sexual dimorphism makes it of interest from anatomical, anthropological, and forensic point of view. The authors who have studied this bone have paid attention either to features relating to its total size or to these of various components such as its inferior border, greater sciatic notch, the symphyseal surface, the acetabulum, the obturator foramen, and the arcuate line [
The male pelvis is heavier and thicker than the female pelvis and usually has more prominent bony markings. The female pelvis is wider, shallower and has a larger pelvic inlet and outlet. Anatomical differences in the human pelvis are more pronounced during pubertal age especially in females. It is believed that sex hormones have a part to play in this variation. In females, the secretion of these hormones increases with age and reaches its peak during adolescence, while in males it was found out that the shape of the innominate bone is transformed to the male type under the influence of androgen [
In the present study, the pubic and ischial length could not identify reasonable percentage of pelvis in both males and females though the mean values of these parameters were statistically significant (
The mean values of ischiopubic index were observed to be statistically significant (
Igbigbi and Msamati [
In the present study, the mean pubic length of males was recorded as 68.73 mm for Lagos State while that of the females was 76.66 mm. The ischial length for Lagos State residents was recorded as 68.93 mm and that of the females was 66.97 mm. These were the lowest when compared to those of other races. For the males, the American Whites and Eskimos had the highest value of 89.4 mm while for the females the Eskimos had the highest ischial length of 81.0 mm followed by American Whites with a value of 78.3 mm [
Population differences which have been observed may be due to environmental or hereditary factors. According to MacLaughlin and Bruce [
The sex differences in the pubic and ischial lengths were found to be statistically significant when male and female data were compared (
In conclusion, this research has provided evidence that the ischiopubic index and the demarking points are reliable in sexing the hip bones of Nigerians (using X-ray films). Thus the ischiopubic index may be of value in forensic and archaeological analyses and in solving medicolegal cases.
The authors declare that there is no conflict of interests regarding the publication of this paper.