Select the incorrect statement.

Options

A. During inspiration intra-pulmonary volume decreases .
B. During expiration intra-pulmonary pressure increases.
C. Contraction of diaphragm increases the volume of thoracic chamber in the antero - posterior axis .
D. Contraction of internal intercostal muscles increases the volume of thoracic chamber in the dorso-ventral axis .

Answer

To solve the question, we need to evaluate each statement provided and determine which one is incorrect.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- **Statement:** "During inspiration, intrapulmonary volume decreases."
- **Analysis:** This statement is incorrect. During inspiration, the diaphragm contracts, leading to an increase in the volume of the thoracic cavity, which in turn increases the intrapulmonary volume. This decrease in pressure allows air to flow into the lungs.
- **Conclusion:** This statement is incorrect.

2. **Evaluate the Second Statement:**
- **Statement:** "During expiration, intrapulmonary pressure increases."
- **Analysis:** This statement is correct. During expiration, the diaphragm and intercostal muscles relax, decreasing the thoracic volume and increasing the intrapulmonary pressure, which forces air out of the lungs.
- **Conclusion:** This statement is correct.

3. **Evaluate the Third Statement:**
- **Statement:** "Contraction of diaphragm increases the volume of thoracic chamber in the anteroposterior axis."
- **Analysis:** This statement is correct. The contraction of the diaphragm indeed increases the volume of the thoracic cavity, particularly in the anteroposterior axis, allowing for more air to be drawn into the lungs.
- **Conclusion:** This statement is correct.

4. **Evaluate the Fourth Statement:**
- **Statement:** "Contraction of the internal intercostal muscles increases the volume of the thoracic chamber in the dorsal-ventral axis."
- **Analysis:** This statement is incorrect. The contraction of internal intercostal muscles primarily aids in forced expiration and decreases the volume of the thoracic cavity, rather than increasing it.
- **Conclusion:** This statement is incorrect.

### Final Conclusion:
The incorrect statements are the first and fourth statements. However, since the question asks for a single incorrect statement, we can conclude that the first statement is the primary focus.