Repetition Training - Basic Lung Sounds Pleural Rubs Lesson Waveform Anatomy play pause Table of Contents 1Crackles - Fine (Rales) 2Crackles - Coarse (Rales) 3Wheeze 4Rhonchi - Low Pitched Wheezes 5Bronchial 6Pleural Rubs Quiz This video is an animation of Pleural Rubs A#421 (lesson# 6) within course number 6. Pleural rubs are discontinuous or continuous, creaking or grating sounds. The sound has been described as similar to walking on fresh snow or a leather-on-leather type of sound. Coughing will not alter the sound. They are produced because two inflamed surfaces are sliding by one another, such as in pleurisy. During auscultation, pleural rubs can usually be localized to a particular place on the chest wall. They also come and go. Because these sounds occur whenever the patient's chest wall moves, they appear on inspiration and expiration. Pleural rubs stop when the patient holds her breath. If the rubbing sound continues while the patient holds a breath, it may be a pericardial friction rub.