Which bone does not participate in the formation of acetabulum ?

Options

A. Pubis
B. Ilium
C. Ischium
D. None

Answer

To determine which bone does not participate in the formation of the acetabulum, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Pelvic Girdle**: The pelvic girdle is made up of two coxal bones. Each coxal bone is formed by the fusion of three bones: ilium, ischium, and pubis.

2. **Identify the Bones Involved**: The three bones that form each coxal bone are:
- Ilium
- Ischium
- Pubis

3. **Locate the Acetabulum**: The acetabulum is a cavity located at the point where the ilium, ischium, and pubis fuse together. It serves as the socket for the femur (thigh bone) to articulate.

4. **Determine Participation in Acetabulum Formation**: Since the acetabulum is formed by the fusion of all three bones (ilium, ischium, and pubis), all these bones participate in its formation.

5. **Analyze the Options**: The question provides the following options:
- Pubis
- Ilium
- Ischium
- None

6. **Conclusion**: Since all three bones (pubis, ilium, and ischium) participate in forming the acetabulum, the correct answer to the question is "none of these."

### Final Answer:
None of these bones (pubis, ilium, ischium) can be excluded as they all participate in the formation of the acetabulum.

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