Feeder arteries, longitudinal arterial trunks and arterial anastomoses of the lower human spinal cord.

1. To study the arterial blood supply of the lower human spinal cord dye was injected into the thickest feeder artery and dinner diameters were measured of the arteries to and in the thoraco-lumbar spinal cord territory. 2. The arterial thoraco-lumbar territory consisted mainly of a ventral (A. spinalis anterior) and 2 dorsolateral longitudinal trunks (Aa. spinalis posterolaterales) linked by 2 sacral anastomoses. These longitudinal trunks were from the spinal cord segment T8 to the conus medullaris comparably thick and were fed to more than 80% by the 2 thickest radicular-medullary arteries. 3. The thickest feeder artery (Artery of Adamkiewicz, A. spinalis magna) had on average an inner diameter of 0.7 mm, contributed according to flow calculations 68% of the blood and fed from the left ventral side, mostly at T10 or L1 levels. The second thickest feeder had an inner diameter of 0.5 mm, supplied 18% of the necessary blood and fed mostly from the left dorsal side at the L1 level. The third thickest feeder with an inner diameter of 0.4 mm, contributed 7% from the left dorsal side. 4. Since the cruciate sacral anastomoses are in 20% of the cases thin or not present, the thickest ventral feeder artery and thickest dorsal feeder artery should be saved in operations in this region. Also the longitudinal arterial trunks should be saved to secure a sufficient blood supply of the cord.