Hamman's sign

Hamman's sign (rarely, Hammond's sign or Hammond's crunch) is a crunching, rasping sound, synchronous with the heartbeat, heard over the precordium in spontaneous mediastinal emphysema.

Etymology
Named for Johns Hopkins's clinician Louis Hamman, M.D.

Examination Findings
This sound is heard best over the left lateral position. It has been described as a series of precordial crackles that correlate with the heart beat and not the respirations. Hamman's crunch is caused by pneumomediastinum or pneumopericardium, and is occasionally associated with tracheobronchial injury and often associated with Boerhaave syndrome (oesophagal rupture).