An abnormal swelling/ widening of the central canal of the spinal cord that leads to a cavity in which cerebral spinal fluid collects.  As the cerebral spinal fluid accumulates, it can put exorbitant amount of pressure on the spinal cord and the surrounding nerves.  The pressure can lead to damage to the nerve cells and their connections causing symptoms like; weakness in the arms and legs, leg stiffness and sensory loss in the neck and arms.  Diagnosis is done using MRI’s.

Hydromyelia is often used interchangeably with syringomyelia.  However, with hydromyelia, the cyst that forms is attached to the fourth ventricle in the brain, and is almost always found in infants and children.  While syringomyelia features a closed cavity almost anywhere along the spinal cord and found primarily in adults.