Abnormal breath sound Crackles 2016-05-09T07:56:43Z SNOMEDCT_US:48409008 Rales are fine, discontinuous crackles that can sound like cellophane being crumpled or velcro being pulled apart. They may be heard with a stethoscope when listening over lungs containing more than the normal amount of fluid secretiions. Crepitations Rales UMLS:C0034642 Crackles are discontinuous, explosive, and nonmusical adventitious lung sounds normally heard in inspiration and sometimes during expiration. Crackles are usually classified as fine and coarse crackles based on their duration, loudness, pitch, timing in the respiratory cycle, and relationship to coughing and changing body position.