Prevalence of occipitalisation in a South African Black population: An original study of 1119 skulls with a review of the literature

Background: Occipitalisation is the most prevalent congenital abnormality at the craniovertebral junction; however, it is rare in the general population. There is a paucity of literature on osteological prevalence studies within the South African Black and broader African populations. This study aimed to establish baseline data for the prevalence of occipitalisation in the South African Black population group. Methods: One thousand two hundred thirteen skulls from a South African Black population were initially sampled, and after exclusion criteria were applied, the sample was reduced to 1119 skulls (male 766; female 353). A morphological description of the skulls that exhibited occipitalisation was included in this study. Results: Occipitalisation was observed in three skulls (3/1119; 0.27 %); two of the skulls were female (2/353; 0.57 %), and one was male (1/766; 0.13 %). The three occipitalised skulls exhibited fusion in three areas of the atlas: the anterior arch, lateral masses, and transverse processes. No skulls exhibited posterior arch fusion of the atlas. Conclusion: This study established a baseline prevalence of occipitalisation in the South African Black population at 0.27 % and found no significant association between sex and occipitalisation (p = 0.236). This study highlights the need for further studies in the other African population affinity groups.