||Background: The morphology of the foramen magnum (FM) is of growing interest among forensic and anthropological experts. It is also important in the surgical management of lesions around the craniovertebral junction. This study elucidates the morphological shapes of the FM in adult Nigerians of Delta state.
Materials and Methods: This retrospective study was conducted at the Radiology Department of a Tertiary Hospital in Delta State, Nigeria following the institution's ethical approval. The FM was identified on skull
computed tomographic images of 336 adult patients (199 males and 137 females). The shape of the foramen was assigned from its appearance and using the foramen magnum index, calculated as length/width. Data analysis was accomplished using Statistical Package for Social Sciences (SPSS) Version 23. Weighted Cohen kappa statistics and intraclass correlation coefficient were used to assess the categorical and continuous variables respectively for inter and intra-observer agreement. The frequencies of the variant shapes were presented in percentages while their association with sex and age were assessed using Chi-square test. P-value was considered significant at <0.05.
Results: The most predominant shape was the oval shape (109, 32.4%) followed by the egg shape (108, 32.1%). The FM shapes did not show any significant association with age or gender (p>0.05). Using the foramen magnum index, the asymmetrical shapes were more 66.7% (224) than the oval FM (112, 33.3%).
Conclusion: The variant morphological shapes of the FM in our studied population highlight the need for preoperative radiological assessment for successful and safe surgeries at the craniovertebral junction.
Key words: foramen magnum, shape, craniovertebral, morphology