What is a pivot joint? Explain with an example.

Explanation

### Step-by-Step Solution:

1. **Definition of Pivot Joint**: A pivot joint is a type of synovial joint that allows for rotational movement around a single axis. In this joint, one bone rotates around another bone, which acts as a pivot point.

2. **Structure of Pivot Joint**: In a pivot joint, one bone has a rounded or cylindrical end that fits into a ring-like structure formed by another bone and a ligament. This structure allows for the rotational movement characteristic of pivot joints.

3. **Example of a Pivot Joint**: A classic example of a pivot joint is found between the first and second cervical vertebrae in the human spine, known as the atlas (first vertebra) and the axis (second vertebra).

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