Which of the following pairs of structures is correctly matched.

Options

A. Tibia and fibula both form parts of knee joint
B. Joint between atlas and axis is pivot joint
C. elbow joint and shoulder joint are the example of ball and socket joint
D. none of these

Answer

To solve the question of which pair of structures is correctly matched, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Option 1: Tibia and Fibula both form parts of the knee joint.**
- The knee joint is primarily formed by three bones: the femur (thigh bone), the tibia (shin bone), and the patella (kneecap).
- While the tibia is indeed part of the knee joint, the fibula does not contribute to the knee joint structure.
- **Conclusion:** This option is incorrect.

2. **Option 2: Joint between atlas and axis is a pivot joint.**
- The atlas (C1 vertebra) and axis (C2 vertebra) form a joint known as the atlantoaxial joint.
- This joint allows for rotational movement of the head, characteristic of a pivot joint.
- **Conclusion:** This option is correct.

3. **Option 3: Elbow joint and shoulder joint are examples of ball and socket joint.**
- The shoulder joint is indeed a ball and socket joint, allowing for a wide range of motion.
- However, the elbow joint is classified as a hinge joint, which allows for bending and straightening motions but not rotational movement.
- **Conclusion:** This option is incorrect.

4. **Option 4: None of these.**
- Since we have identified that Option 2 is correct, this option is not applicable.
- **Conclusion:** This option is incorrect.

### Final Answer:
The correctly matched pair is **Option 2: Joint between atlas and axis is a pivot joint.**

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