What is a ganglion cyst?

Inflamed tendon: Tendons run in sheaths, similar to the cables on a bicycle. Sometimes a minor trauma can cause the sheath to become inflamed and a small cyst can pop up. This is called a ganglion cyst. They are usually painless and sometimes go away on their own. If it isn't bothering you then you likely don't need to do anything with it. If it is bothering you, see your doc about removing it.

Rupture: A ganglion cyst is a contained rupture of the synovial capsule between the small bones of the wrist or ankle. The body will try to isolate the thick, jelly-like fluid and it gets contained in a cyst-like capsule.

Cysts from a joint: There are not many problems associated with the wrists short of bony abnormalities. One common problem that can occur at the level of the wrists or coming from any joint is called a ganglion cyst. Ganglion cysts are not usually associated with much pain or discomfort until they become large. They extends from the joint space. It's, like blowing up a tiny balloon from between your knuckles. These often bust when a person bumps them. They will reoccur unless they are surgically tied off. I suggest you see an orthopedic surgeon to further assess and evaluate.