Subcutaneous emphysema may obscure the detection of pleural air. There is a partially opacified pleural-based inwardly convex opacity within the left midlung, adjacent to a displaced left fifth rib fracture, which could represent a small pneumothorax or loculated hydropneumothorax.
Acute rib fracture (Present) Subcutaneous Emphysema (Present) Hydropneumothorax (Uncertain) Simple pneumothorax (Uncertain)