Which of the following is NOT an inspiratory muscle?

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: In obstructive lung disease (e.g., COPD), expiration becomes active due to airway obstruction, and expiratory muscles may be used even at rest. The diaphragm is primarily inspiratory, and external intercostals aid inspiration. The diaphragm being 'only' inspiratory is true, not false, suggesting a possible error in the key.