[Spontaneous pneumomediastinum in adults]. / Pneumomédiastin spontané de l'adulte.

Pneumomediastinum is an uncommon, often overlooked, condition resulting from the rupture of perivascular alveoli and the migration of air along the pulmonary vessels. Diagnosis, which is usually difficult, rests on three major signs: cervical subcutaneous emphysema, Hamman's sign and roentgenological findings. Prognosis is good and the course is uneventful. Cervico-mediastinotomy is only rarely reeded.