Crepitus: The grating sound heard, and the sensation felt when two rough surfaces rub together. Crepitus may be experienced when the ends of a broken bone rub against each other, or in osteoarthritis when the cartilage that covers the bony surfaces of a joint has worn and the roughened areas of the joint grind against each other.The sound is usually loud enough to be heard by the naked ear. Fainter sounds, audible through a stethoscope, are produced in the lung as a result of inflammation-due to pneumonia, for example.

The term "crepitus" is also used to describe the sounds made when an area of air under the skin (see Emphysema, surgical) or gas gangrene (gas infected tissue) is pressed.

Bibliography: I. Medicine, Popular-Dictionaries. I.morgan, Peter, 1927- .II. Canadian Medical Association.III. Reader's Digest Association(Canada). IV. Title: Home medical encyclopedia.