Soft tissue emphysema following alveolar disruption

Air from torn alveolus first enters perivascular interstitium (A), dissecting proximally within the bronchovascular sheath toward the mediastinum (B). As airway pressure rises, decompression occurs into cervical (C), subcutaneous (D), and pericardial (E) tissue spaces. Pleural rupture may result in pneumothorax (F). Small arrows indicate the direction of air movement.