Final answer:
The atlas vertebra, or C1 vertebra, has unique features including a ring shape, differently shaped transverse processes, and distinct articular processes.
Step-by-step explanation:
The atlas vertebra, also known as the C1 vertebra, has several distinct features that differentiate it from other cervical vertebrae. It does not have a body or spinous process, instead, it consists of an anterior and posterior arch forming a ring shape. The transverse processes of the atlas are longer and extend more laterally compared to other cervical vertebrae. The superior articular processes are deeply curved and face upward, while the inferior articular processes are flat and face downward, joining with the superior articular processes of the C2 vertebra.