Anthropometric study of ischiopubic index of the Isoko and Benin in Nigeria

Background : The ischiopubic index is calculated by dividing the pubic length by the ischial length and multiplying by 100. It has been said to be one of the parameters affecting the pelvic inlet and this is of interest to obstetricians and anatomic anthropologists.Objectives : To determine and compare the pubic length, ischial length and ischiopubic index among the males and females of Isoko and Bini ethnic groups of Nigeria.Design : A retrospective cross sectional study.Setting: University of Benin teaching hospital (UBTH), Irrua Specialist teaching hospital (ISTH) and Eku Baptist Hospital.Subjects: Four hundred antero-posterior radiographs ; two hundred for the Isoko (males 105 and females 95) and two hundred also for the Bini (males 110 and females 90) adult pelvis in the age range of 18 – 65 years were evaluated.Results : Pubic length, ischial length, and ischiopubic index were measured. The mean pubic length, mean ischial length and mean ischiopubic index of Isoko males are respectively (mm) 78.42±3.40,69.41±5.10, 75.2-97.5, 87.52 ±1.30. The range and point of demarcation are (mm): 75.2-97.5, <86.22. For Isoko females, the mean pubic length, mean ischial length and mean ischiopubic index are (mm): 81.20 ±5.0, 74.30±6.10, 106.21±9.10. The range and demarcation point are (mm): 87-125.10, <97.11. The mean pubic length, mean ischial length and mean ischiopubic index of Bini males are respectively (mm): 74.32±5.40,82.71 ±7.20, 88.72±2.40. The range and point of demarcation are (mm) 70-98,<86.32. For Bini females they are (mm); 86.48±4.20, 78.61±7.41, 112.21±7.71. The range and point of demarcation are (mm): 84.1-132.50, <104.50 respectively.Conclusion: The study showed sexual dimorphism in the ischipubic index of the study population and a significant difference in actual mean values and demarking points between the two population groups studied. This contributes growing database of anthropologically and obstetrically significant data for ethnic groups in Nigeria and could help in identification of skeletal remains in the hitherto restive Nigerian Niger-Delta region