craniovertebral junction

The cervical vertebrae, comprising the uppermost segment of the vertebral column, include seven vertebrae (C1–C7) with unique features like a bifid spinous process and transverse foramina, supporting neck mobility and nerve passage. The atlas (C1) and axis (C2) have specialized structures, such as the dens and anterior arch, enabling head rotation and support. This article provides an in-depth exploration of the cervical vertebrae’s anatomy, physical characteristics, and functional roles, offering a comprehensive guide to their significance in spinal health.

The CT scan image displays an axial view of the first cervical vertebra (C1), also known as the atlas, with a notable unfused posterior arch highlighted by the red arrow. This congenital anomaly represents a failure of proper fusion during embryonic development of the posterior neural arch components.

The median sagittal section through the craniovertebral junction reveals the intricate relationships between osseous structures and ligamentous complexes that enable controlled head movement while maintaining stability. This critical region demonstrates sophisticated anatomical arrangements that protect vital neural structures while facilitating complex motion patterns between the skull and upper cervical vertebrae.

The posterior ligamentous structures connecting the occiput, atlas (C1), and axis (C2) form a sophisticated network essential for craniovertebral stability and mobility. These ligamentous complexes play a crucial role in maintaining the integrity of the upper cervical spine while allowing controlled head movements. Understanding these structures is fundamental for clinicians dealing with upper cervical spine pathologies and surgical interventions.