Herman sign

Hamman's sign (Hamman's sign) is one of the signs of mediastinal emphysema. As the heartbeat hits the emphysema of the mediastinum, auscultation can be heard as a kind of grazing crooked or Iraqi rolling sound. This sound is more apt to be heard at the apex, the lower end of the sternum, or the left edge of the lower end of the sternum, especially when sitting, standing, and lying on the left side.