Each patients experiences a different combination of symptoms. A watery, protective substance known as cerebrospinal fluid normally flows around the spinal cord and brain, transporting nutrients and waste products. It also serves to cushion the brain. A number of medical conditions can cause an obstruction in the normal flow of cerbrospinal fluid, redirecting it into the spinal cord itself. For reasons that are only now becoming clear, this results in syrinx formation.
Cerbrospinal fluid fills the syrinx.
Pressure differences along the spine causes the fluid to move within the cyst. Physicians believe this continual movement of fluid, is what results in cyst growth and further damage to the spinal cord.