TERMINOLOGY (SYNONYMS)

• Facet joint ganglionic cyst
  
• Facet cyst
  
• Spinal joint cyst
  

INTRODUCTION

A synovial cyst in the spine arises from a spinal (facet) joint. The joint is usually degenerative. The fluid level expands in the involved spinal joint causing the lining of the joint (synovium) to expand to accommodate the increased pressure. This results in an extension of the synovium away from the outer border of the facet joint complex. Facet cysts usually project in an anterior and medial direction. This places the cyst in the spinal canal and/or within the neuroforamen, which refers to an opening along the side of the spine where the spinal never traverses.

PREVALENCE

Facet joint synovial cysts are more common in individuals over 60 years old. They occur more commonly in females. There is no racial predilection. They are most likely to develop at the site of a degenerative spinal joint.