Vascular architecture of the developing spinal cord in the rat: a suggested model.

The vascular architecture of the developing Sprague-Dawley rat spinal cord from E11 through E16 is reported. The paraffin-embedded cord is serially sectioned in the sagittal, transversal and frontal planes and stained with PAS and methenamine silver. Serial semithin transverse sections are stained with toluidine blue. The results demonstrate two highly integrated vascular systems: one sagittally disposed in three concentric networks and the other radially oriented around the cord. The sagittal plexus is configurated by rhombohexagonal polygons. The lateral radial stem vessels anastomose with the sagittal systems at the polygonal vertex. A structural vascular model of the cord is proposed. The periodical sequence distribution of vessels in the three planes and their relationship to spinal ganglia is suggestive of a neural metamera vascularly determined.