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.
Locked knee caused by meniscal subluxation: Magnetic resonance imaging and arthroscopic verification. George M, Wall EJ. âLocked knee caused by meniscal subluxation: Magnetic resonance imaging and arthroscopic verificationâ.Arthroscopy 2003; 19(8):885-888. Abstract: Subluxation or dislocation of an intact lateral meniscus is a controversial and rarely reported cause of knee pain and locking.RI showed anterior dislocation of the posterior horn of the lateral meniscus with the knee in the locked position. The MRI was immediately repeated after the author reduced (manipulated) the locked knee into extension. On the repeat MRI, the lateral meniscus had returned to a normal position.