atlantoaxial instability

The atlantoaxial joint is a pivot type of synovial joint located between the dens of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), secured by ligaments, enabling rotational movement of the head. This joint plays a crucial role in allowing side-to-side head rotation, such as when shaking the head to say “no,” while maintaining stability in the upper cervical spine. This article explores the anatomical structure of the atlantoaxial joint, its physical functions, and its significance in neck mobility.

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.