Which one of the following statements is true?

Options

A. Head of humerus bone articulate with acetabulum of pectoral girdle
B. Head of Humerus bone articulates with glenoid cavity of pectoral girdle
C. Head of humerus bone articulates with a cavity called acetabulum of pelvic girdle.
D. Head of humerus bone articulates with a glenoid cavity of pelvic girdle.

Explanation

To determine which statement is true regarding the pectoral girdle and its relation to the humerus, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Pectoral Girdle**: The pectoral girdle is a crucial part of the skeletal system that connects the upper limb (arm) to the axial skeleton. It consists primarily of two bones: the scapula (shoulder blade) and the clavicle (collarbone).

2. **Identify the Joint Type**: The shoulder joint formed by the pectoral girdle is a ball and socket joint. This allows for a wide range of motion for the arm.

3. **Examine the Bones Involved**: The scapula has a specific cavity known as the glenoid cavity, which is where the head of the humerus (the bone of the upper arm) articulates.

4. **Analyze the Statements**:
- **Statement 1**: "Head of humerus bone articulates with acetabulum." - This is incorrect because the acetabulum is part of the pelvic girdle, not the pectoral girdle.
- **Statement 2**: "Head of humerus bone articulates with glenoid cavity of pectoral girdle." - This statement is correct as the head of the humerus fits into the glenoid cavity to form the shoulder joint.
- **Statement 3**: "Head of humerus articulates with acetabulum of pelvic girdle." - This is incorrect for the same reason as Statement 1.
- **Statement 4**: "Humerus bone articulates with glenoid cavity and pelvic girdle." - This is also incorrect as the humerus articulates only with the glenoid cavity of the pectoral girdle.

5. **Conclusion**: After analyzing all the statements, the true statement is: "Head of humerus bone articulates with glenoid cavity of pectoral girdle."

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

---