Which of the following is not correct the thoracic chamber in humans ?

Options

A. It is an air tight chamber is which lungs are situated.
B. It is formed ventrally by sternum and dorsally by ribs.
C. It is formed on the lower side by the dome shaped diaphragm.
D. Both (A) and (C)

Answer

To determine which statement about the thoracic chamber in humans is incorrect, we will analyze the provided statements one by one.

### Step-by-Step Solution:

1. **Understanding the Thoracic Chamber**: The thoracic chamber, also known as the thoracic cavity, is the space within the chest that houses the lungs and other structures. It is important for respiration.

2. **Evaluating Statement 1**: The first statement claims that the thoracic chamber is an airtight chamber with lungs situated in it.
- **Analysis**: This statement is correct. The thoracic cavity is indeed airtight, which is essential for the process of breathing (ventilation). The lungs are located within this airtight chamber.

3. **Evaluating Statement 2**: The second statement indicates that the thoracic chamber is made up of the ventrally located sternum and dorsally located ribs.
- **Analysis**: This statement is incorrect. While the sternum is located ventrally (at the front), the ribs are not located dorsally (at the back). Instead, the ribs are positioned laterally (on the sides) of the thoracic cavity. The dorsal part is actually formed by the vertebral column (spine).

4. **Evaluating Statement 3**: The third statement mentions that on the lower side, the thoracic chamber is made of a dome-shaped diaphragm.
- **Analysis**: This statement is correct. The diaphragm is indeed a dome-shaped muscle that forms the floor of the thoracic cavity and plays a crucial role in the breathing process.

5. **Conclusion**: Based on the evaluations, the incorrect statement about the thoracic chamber is **Statement 2**.

### Final Answer:
The statement that is not correct about the thoracic chamber in humans is: **"It is made up of Ventrally Sternum and Dorsally Ribs."**

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