Ganglion is a fluid filled sac which can occur around any joint or around tendons. Dorsal wrist ganglion is very common problem of wrist joint. This dorsal wrist ganglion occurs due to injury to wrist joint and this injury make a rent in joint capsule. The fluid from wrist joint escape through this rent and accumulate in sac and the valve on rent is one way valve so this fluid will not go back to wrist joint.