A pivot joint can be found between :

Options

A. clavicle and sternum
B. radius and ulna
C. scapula and humerus
D. tibia and fibula

Explanation

To solve the question "A pivot joint can be found between:", we will analyze the options provided and determine which pair of bones forms a pivot joint.

### Step-by-Step Solution:

1. **Understanding Joint Types**:
- First, we need to understand what a pivot joint is. A pivot joint allows for rotational movement around a single axis.

2. **Analyzing the Options**:
- **Option A: Clavicle and Sternum**:
- The joint between the clavicle and sternum is called the sternoclavicular joint. This is a synovial joint, not a pivot joint.
- **Conclusion**: Incorrect option.

- **Option B: Radius and Ulna**:
- The radius and ulna are the two bones in the forearm. The joint between them, specifically at the proximal end near the elbow, allows for rotation of the forearm (like turning the palm up and down). This is indeed a pivot joint.
- **Conclusion**: Correct option.

- **Option C: Carpals and Humerus**:
- The joint between the carpals (wrist bones) and the humerus (upper arm bone) is a ball-and-socket joint, which allows for a wide range of movement, not just rotation.
- **Conclusion**: Incorrect option.

- **Option D: Tibia and Fibula**:
- The joint between the tibia and fibula is a type of synovial joint, specifically a syndesmosis joint, which allows for slight movement but does not allow for rotation like a pivot joint.
- **Conclusion**: Incorrect option.

3. **Final Answer**:
- Based on the analysis, the correct answer is **Radius and Ulna**.