What is Hamman's crunch?

Hamman's crunch refers to a distinctive sound that can be heard over the precordium during auscultation, typically associated with pneumothorax or esophageal perforation. This phenomenon occurs when air present in the mediastinum creates a crunching, rasping sound that coincides with the heartbeat and is often described as a "crunch" by clinicians.

The sound itself derives from the movement of air in the soft tissues of the mediastinum, creating a characteristically different auscultatory finding compared to lung sounds, despite occurring during the cardiac cycle. This can be an important diagnostic clue in emergent situations.

In contrast, other sounds such as a high-pitched wheeze typically indicate bronchospasm or airway obstruction, a rumbling sound in the abdomen is more associated with gastrointestinal processes like borborygmi, and a clicking sound in the joints indicates joint movement rather than a respiratory or cardiovascular phenomenon. Thus, the uniqueness and clinical significance of Hamman's crunch makes it a noteworthy sign in the context of certain thoracic conditions.