I have a pea size knot on the back of my hand.  Its like its attached to the tendon of my middle finger.  When I bend that finger, it moves forward.  When I straighten the finger, it moves back where it started.  It doesnt move when I bend the other fingers.  What is it?
Hi, This is likely to be a ganglion. This is a cyst-like swelling in the tendon. It is not serious. If it is causing pain, it can easily be removed by a minor surgical procedure.  Chat Doctor.