Which of the following is not the example of synovial joint?

Options

A. Between humerus and pectoral girdle
B. Between atlas and axis
C. Between carpal and metacarpal of thumb
D. Between the adjacent vertebrae

Answer

To determine which of the following options is not an example of a synovial joint, we need to first understand what synovial joints are and then analyze each option provided.

### Step-by-Step Solution:

1. **Define Synovial Joints**:
- Synovial joints are characterized by the presence of a synovial cavity filled with synovial fluid, which lubricates the joint, allowing for smooth movement. Examples include ball-and-socket joints, hinge joints, pivot joints, saddle joints, and more.

2. **Analyze Each Option**:
- **Option 1: Joint between humerus and pectoral girdle**:
- This is a ball-and-socket joint (shoulder joint), which is a type of synovial joint.
- **Conclusion**: This option is a synovial joint.

- **Option 2: Joint between atlas and axis**:
- The atlas (C1) and axis (C2) are cervical vertebrae that form a pivot joint, allowing for rotational movement of the head.
- **Conclusion**: This option is a synovial joint.

- **Option 3: Joint between carpal and metacarpal of the thumb**:
- This joint is a saddle joint, which is also a type of synovial joint.
- **Conclusion**: This option is a synovial joint.

- **Option 4: Joints between adjacent vertebrae**:
- The joints between adjacent vertebrae are connected by intervertebral discs, which are cartilaginous joints. They do not have a synovial cavity and do not contain synovial fluid.
- **Conclusion**: This option is NOT a synovial joint.

3. **Final Answer**:
- The option that is not an example of a synovial joint is **the joint between adjacent vertebrae**.