What is the definition or description of: ganglion?

Cyst of a joint: Commonly associated with trauma or arthritis the joint capsule becomes stretched. As the body produces additional synovial fluid to lubricate the joint the loosened joint capsule stretches and fills with fluid...The gnaglion. As the body produces more or less the size of the ganglion will fluctuate. Best treatment includes surgical removal.

Benign cyst mass: Ganglion cysts arise from joint, and commonly cause local discomfort from a mass effect. They are filled with viscous sterile fluid, essentially an ultra-filtrate of the joint or synovial fluid. They are generally benign. Treatment is symptomatic, from observation to surgical excision.

Is:: The herniation or out-pouching or distention of a weakened portion of a joint capsule or tendon sheath.

Sac: A fluid filled sac that arise from a joint or tendon sheath.