• There is an ovoid bright signal intensity in cord at T6 consistent with a small syrinx. Deformity of the posterior surface of the spinal cord is seen at this level , with a scalpel sign. This has a focal rather than more broad indentation. There is however a slender amount of anterior csf which is preserved going against idiopathic cord herniation. The appearances are suggestive of an arachnoid webb which can be sen on the ciss sequence