Anthony Anderson Has Bright Yellow Fluid Drained From Knee, on Video

Anthony Anderson hustled to the hospital to get a steady flow of fluid out of his knee ... and, he uploaded it to social media to disturb all his fans' dreams for years to come.

The actor posted an update about his medical anomaly Wednesday ... revealing he had to rush on over to the ER Sunday night after his knee ballooned up way past its normal size.

Check out the clip ... AA's laid back in the hospital room while a doc puts a huge syringe directly into his leg -- slowly pulling the plunger back.

Yellow fluid rushes into the tube, filling it all the way up. The doctor switches tubes and does it all again ... two huge syringes filled with viscous material pulled from the star and disposed of.

Anderson says he was told he has arthritis in his knee ... adding the doctors ultimately drained 140cc out of his extremity. He thanked the doctors at UCLA Santa Monica and his son, Nate.

The before and after pics are a sight to behold BTW ... the knee is half the size after the fluid drain -- if not even smaller than that.