Sacro-iliac joint is `:-`

Options

A. Mavable
B. Immovable
C. Imperfect
D. None

Answer

### Step-by-Step Solution:

1. **Definition of Sacroiliac Joint**: The sacroiliac joint is the joint that connects the sacrum (the triangular bone at the base of the spine) to the ilium (the uppermost part of the pelvis).

2. **Anatomical Location**: The sacrum is located at the bottom of the spine, and it connects on both sides to the ilium, which is part of the hip structure.

3. **Function of the Joint**: The primary function of the sacroiliac joint is to transmit the weight and forces from the upper body to the pelvis and legs. This is crucial for maintaining stability and balance during various activities.

4. **Mobility of the Joint**: The sacroiliac joint is characterized by very limited movement. It is designed for stability rather than mobility, which means it does not allow for a wide range of motion.

5. **Conclusion**: Given that the sacroiliac joint is strong, stable, and allows for very little movement, it is classified as an immovable joint.

### Final Answer:
The sacroiliac joint is **immovable**.

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