When we rotate our neck :-

Options

A. Occipetal condyles rotate on Atlas
B. Axis`(C_(2))` bone rotates on Atlas
C. Axis and atlas both bones other
D. Atlas rotated on axis

Answer

### Step-by-Step Solution:

1. **Identify the Key Vertebrae**: When we rotate our neck, the key vertebrae involved are the atlas (C1) and the axis (C2). The atlas is the first cervical vertebra that supports the skull, while the axis is the second cervical vertebra that allows rotation.

2. **Understand the Structure and Function**: The atlas and axis are specialized vertebrae designed to allow a greater range of motion compared to normal vertebrae. This specialization enables us to nod our head up and down and rotate it side to side.

3. **Role of the Atlanto-Occipital Joint**: The atlanto-occipital joint, formed between the atlas and the occipital bone of the skull, allows the head to nod up and down. This joint is crucial for the flexion and extension movements of the neck.

4. **Role of the Dens**: The dens (or odontoid process) of the axis acts like a pivot. It allows the atlas, and consequently the head, to rotate around it. This pivoting action is essential for the side-to-side rotation of the head.

5. **Conclusion**: In summary, when we rotate our neck, the atlas rotates around the dens of the axis, allowing for a wide range of motion in the cervical region of the spine.

### Final Answer:
When we rotate our neck, the atlas rotates on the axis, facilitated by the specialized structure of these vertebrae, allowing for a greater range of motion than normal vertebrae.

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