Arterial vascularization of the cauda equina.

UNLABELLED: Vascular injection of eleven perinates revealed that each lumbosacral spinal-nerve root received its intrinsic blood supply from both distal and proximal radicular arteries through which the blood flowed toward a mutual anastomosis in the proximal one-third of the root. Segmental arteries supplied the distal vessels while their proximal equivalents received blood from their respective anterior or dorsolateral spinal arteries, which derived their flow from the large, irregularly located medullary arteries. CLINICAL RELEVANCE: The region of relative hypovascularity formed below the conus by the combined areas of anastomoses in the cauda equina may provide an anatomical rationale for the suspected neuroischemic manifestations concurrent with degenerative changes in the lumbar spine.