Computed Tomography Assessment of Nasal, Orbital Indices and Volume among Igbo, Calabari and Ogoni Residents of Portharcourt, Rivers State, Nigeria

Background: Understanding the morphology of the orbital and nasal cavities is essential for human identification, reconstructive surgeries and forensic medicine. Objectives: To evaluate the orbital and nasal dimensions and their relationship with gender in the Igbo-, Calabari- and the Ogoni ethnic groups living in Port-harcourt Nigeria using computed tomography (CT). Methods: Four hundred and sixty-six head CT images were analyzed. 43.8% were Igbos’, 28.8% Calabaris’ and 27.5% Ogonis’ of 20-80 years of age with a mean age of 51.19±15.67. Males and females were 55.8% and 44.2% respectively. Parameters measured were orbital height (OH), orbital width (OW), orbital depth (OD), nasal height (NH) and nasal width (NW) using the ImageJ software. Data analysis was by SPSS version 20. Differences between groups were obtained using the one-way ANOVA. P-value < 0.05 was considered statistically significant. Results: Mean orbital volume for the Igbos’, Calabaris’ and Ogonis’ are 48.57±7.38, 48.97±5.63 and 46.27±5.59 for the right and 48.56±7.31, 48.96±5.62 and 46.32±5.56 for the left respectively P<0.05. Mean OD is highest in the Igbos’ 4.70±0.32 while mean OH is highest in the Calabaris 2.94±0.18 (P< 0.05). Igbos have the highest mean NI of 89.71. Males have higher NI P<0.05 in all ethinic groups. Mean OI shows no sexual dimorphism or unilaterality P>0.05 Conclusion: Differences in the measured parameters and sexual dimorphism in the nasal indices only among the ethnic groups is demonstrated.  Microseme and platyrrhine categories of orbital and nasal cavities respectively is similar to all. These findings will aid facial reconstructive surgeries and forensics.