Which vertebra is referred to as the "atlas"?

The term "atlas" refers specifically to the C1 vertebra, which is the first cervical vertebra in the spinal column. This vertebra is named after the mythological figure Atlas, who was said to hold up the world. The C1 vertebra's primary role is to support the skull and allow for the nodding motion of the head, leading to its nickname. It articulates with the occipital bone at the base of the skull, enabling this flexibility. The unique structure of the atlas, which lacks a typical vertebral body and instead has a ring-like formation, is crucial for its function in supporting the deceased weight of the skull and providing a pivot point for head movement. This specialized function further distinguishes it from other vertebrae in the cervical, lumbar, or sacral regions, which serve different roles in supporting the spine.