What is it?

Ganglia are small cysts. They contain a thick jelly-like material called synovial fluid. Ganglia are also called ganglion cysts.

Ganglia are usually attached to a joint or tendon. They appear on the back of the wrist and the top of the foot next to the small joints. They can also appear on the knee. They look like small bumps.

Ganglia are common and usually harmless. It’s not clear what causes them. If these cysts bother you or cause pain, you can talk to your GP about removing them.