Most serious injury is at: (A) open pneumothorax, (B) diaphragmatic injury, (C) Flail chest, (D) Single rib fracture
Answer is A. Answer- A. open pneumothoraxThis is a large open defect in the chest (> 3 cm), leading to equilibration between intrathoracic and atmospheric pressure.Air accumulates in the hemithorax (rather than in the lung) with each inspiration, leading to profound hypoventilation on the affected side and hypoxia.