What is a synovial cyst in your spine?

Fluid sac . This is a fluid filled sac that arises from degeneration of the facet joints. When present they usually occur in the lumbar spine, mainly l4-5 & l5-s1. Symptoms result from formation of spinal stenosis with resulting irritation of the affected nerve root. Since cysts are a result of degenerative changes, they usually are not present until after the age of 40.