1727, from Japanese samurai warrior, knight, originally the military retainer of the daimio, variant of saburai, nominal form of sabura(h)u to be in attendance, to serve..
The bubbles make a noise when they burst. This is called cavitation. Another cause for painless popping in the knee is when the ligaments and tendons catch as they go over a bony lump and pop when they snap back into place. Or the clicking and popping may be caused by catching on soft tissue or scar tissue within the knee.
There are many more less common causes of knee snapping and popping. The issues mentioned above usually cause painful snapping and popping within the knee. If you have painful popping, snapping and swelling you should see your doctor. Many of you will have painless knee popping and snapping. Sometimes our knee pops or snaps for no known reason. In many situations it is simply ânormalâ and no treatment is necessary.