Which of the following is not a part of the axial skeleton?

Options

A. Sternum
B. Coxal bone
C. Coccyx
D. Atlas

Answer

To determine which of the following is not a part of the axial skeleton, we need to understand the components of both the axial and appendicular skeletons.

### Step-by-Step Solution:

1. **Define Axial Skeleton**: The axial skeleton consists of the bones that form the long axis of the body. It includes the skull, vertebral column (spine), and rib cage (thoracic region).

2. **Define Appendicular Skeleton**: The appendicular skeleton includes the bones of the limbs and the girdles (shoulder bones and hip bones) that attach them to the axial skeleton.

3. **List the Options**: The options provided in the question are:
- Sternum
- Coxal Bone
- Coccyx
- Atlas

4. **Analyze Each Option**:
- **Sternum**: This is a flat bone located in the chest (thoracic region) and is part of the axial skeleton.
- **Coxal Bone**: Also known as the hip bone, it is part of the appendicular skeleton, as it connects the lower limbs to the body.
- **Coccyx**: This is the tailbone located at the end of the vertebral column and is part of the axial skeleton.
- **Atlas**: This is the first cervical vertebra that supports the skull and is also part of the axial skeleton.

5. **Identify the Answer**: Among the options, the coxal bone is the only one that is not part of the axial skeleton. It belongs to the appendicular skeleton.

### Final Answer:
The coxal bone is not a part of the axial skeleton.

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