Prepatellar bursitis (also known as beat knee, carpet layer's knee, coal miner's knee, housemaid's knee, rug cutter's knee, or nun's knee) is an inflammation of the prepatellar bursa at the front of the knee. It is marked by swelling at the knee, which can be tender to the touch but which does not restrict the knee's range of motion. It is most commonly caused by trauma to the knee, either by a single acute instance or by chronic trauma over time. As such, prepatellar bursitis commonly occurs among individuals whose professions require frequent kneeling.