Pneumomediastinum
Upper Respiratory Tract
Head and neck infection (odontogenic, salivary glands, cervical adenitis, tonsillitis, peritonsillar abscess, osteomyelitis of facial bones)
Fractures (involving paranasal sinuses, orbit, mandibles, other facial bones)
Other mucosal disruption (trauma, surgery, attempted endotracheal intubation)
Dental procedures (extractions, air-turbine drilling)
Intrathoracic Airways
Blunt or penetrating chest trauma
Foreign body
Iatrogenic (bronchoscopy, bronchial brushing, transbronchial biopsy, needle aspiration)
Neoplasm
Lung Parenchyma
Direct disruption of alveoli (penetrating trauma, surgery, transbronchial biopsy, needle aspiration)
"Spontaneous" alveolar rupture (between alveolus and adjacent bronchovascular sheath) *
Gastrointestinal Tract
Esophageal perforation
Via pneumoperitoneum or pneumoretroperitoneum (gastric or intestinal perforation, diverticulitis, pneumatosis cystoides intestinalis, endoscopy, biopsy, infection)
Infection with gas-producing organisms
Acute bacterial mediastinitis
Head and neck infections
Air from Outside the Body
Penetrating trauma to neck or chest
Surgical procedures (tracheotomy, mediastinoscopy, sternotomy)
Via subcutaneous emphysema in association with chest tube insertion
Artificial pneumothorax
Artificial pneumoperitoneum
Alveolar Rupture: Reported Clinical Settings