Which description refers to the first and second cervical vertebrae?

• A. C-spine
• B. Atlas-axis complex
• C. C1, C2
• D. Cervical vertebrae one and two

Answer: (C)

The first two cervical vertebrae are identified by their standard names and numbers, C1 and C2. This direct labeling makes it crystal clear which bones are being discussed. C1 is the atlas, which supports the skull and mainly permits nodding, while C2 is the axis, which has the dens that acts as a pivot for rotation of the head. Together, they form the atlas-axis complex, highlighting their close functional relationship, but when you need to name the bones themselves, the precise identifiers C1 and C2 are the most straightforward and unambiguous way to refer to the pair. Other descriptions can be correct in different contexts (like noting the atlas-axis complex for function, or calling the region the C-spine for the broader area), but for specifically naming the first and second cervical vertebrae, using C1 and C2 is best.