Which one of the following statements is true:

Options

A. Head of humerus bone articulates with acetabulum of pectoral girdle
B. Head of humerus bone arti~ulates with " glenoid cavity of pectoral girdle
C. Head of humerus bone articulate with a cavity called acetabullum of pelvic girdle
D. Head of humerus bone articulates with a glenoid cavity of pelvic girdle.

Answer

To determine which statement is true regarding the articulation of bones in the context of locomotion and movement, we will analyze each statement provided.

### Step-by-Step Solution:

1. **Understanding the Articulation of Bones**:
- The humerus is the bone of the upper arm, and it articulates with the shoulder girdle.
- The pelvic girdle contains the acetabulum, which is the socket for the femur, the thigh bone.

2. **Evaluating the Statements**:
- **Statement 1**: "Head of humerus bone articulates with acetabulum of pectoral girdle."
- This statement is incorrect. The head of the humerus articulates with the glenoid cavity of the scapula, which is part of the pectoral girdle, not the acetabulum.

- **Statement 2**: "Head of humerus bone articulates with the glenoid cavity of pectoral girdle."
- This statement is correct. The head of the humerus fits into the glenoid cavity, allowing for a wide range of motion in the shoulder.

- **Statement 3**: "Head of humerus bone articulates with the acetabulum of pelvic girdle."
- This statement is incorrect. The head of the femur articulates with the acetabulum of the pelvic girdle, not the humerus.

- **Statement 4**: "Head of lumbar bone articulates with the glenoid cavity of pelvic girdle."
- This statement is incorrect. Lumbar vertebrae do not articulate with the glenoid cavity; they are part of the vertebral column and articulate with other vertebrae and the pelvis.

3. **Conclusion**:
- The only true statement is **Statement 2**: "Head of humerus bone articulates with the glenoid cavity of pectoral girdle."

### Final Answer:
The true statement is: **Head of humerus bone articulates with the glenoid cavity of pectoral girdle.**

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