The prevalence of unclosed transverse foramina in the cervical spine of a South African population sample

PURPOSE: Unclosed transverse foramina (UTF) represent anatomical variations of the cervical vertebrae that may influence vertebral artery, vein or sympathetic nerves, particularly at the level of the atlas (C1). This study aimed to determine the prevalence and distribution of UTF in a South African skeletal population and to evaluate associations with age, biological sex, and population affinity. METHODS: A macroscopic osteological assessment of cervical vertebrae from 800 individuals was performed using a South African skeletal repository. UTF were identified based on incomplete osseous closure of the transverse foramen. Prevalence was assessed at individual and vertebral levels, and demographic associations were analyzed statistically. RESULTS: UTF were identified in 17.4% of individuals and 2.9% of total vertebrae. The highest prevalence occurred at C1, followed by C3 and C6. Unilateral UTF were more common than bilateral, with a right-sided predominance. UTF were observed more frequently in males, individuals younger than 50 years, and those of Black African population affinity, with the highest prevalence in the Sotho subgroup. A weak but significant association with younger age was noted at the C2 and C7 levels (p < 0.05). CONCLUSION: UTF are common anatomical variants in this South African population, with prevalence influenced by vertebral level and demographic factors. Recognition of UTF is important for accurate radiological interpretation and for surgical and manual procedures involving the cervical spine, where altered neurovascular anatomy may affect procedural planning and safety.