Spontaneous pneumomediastinum.

Spontaneous pneumomediastinum, or Hamman's syndrome, is a rare condition which may present with the symptoms of chest pain, dyspnoea, dysphagia, or neck pain. The signs of subcutaneous emphysema and Hamman's crunch (the presence of a crepitance sound that varies with the heartbeat on auscultation of the precordium) are usually present. A case of this syndrome occurring in an elderly patient with none of the recognised risk factors is presented.