<unk>  is widening or ballooning of the<unk>  sac surrounding the spinal cord. This usually occurs in the lumbosacral region, as this is where the cerebrospinal fluid pressure is greatest, but the spinal canal can be affected in any plane.
Dural ectasia
Arteriovenous fistula
Pseudoaneurysm
Dural arteriovenous fistula
Developmental venous anomaly
Jugular vein ectasia
Collapsed vein
Vascular ring