MORPHOLOGY OF THE HUMAN INTERNAL VERTEBRAL VENOUS PLEXUS - A CADAVER STUDY AFTER INTRAVENOUS ARALDITE CY-221 INJECTION

Reviewing the literature on the vascular anatomy of the spinal epidura l space, it appeared that the knowledge of the internal vertebral veno us plexus is limited, Injection studies of the entire internal vertebr al venous plexus after application of modern techniques, to the best o f our knowledge, have never been performed, Based on the clinical impo rtance of these structures, it was decided to study the human vertebra l venous system after Araldite CY 221 injection, in order to update th e morphological characteristics of the internal vertebral venous syste m, The vertebral venous systems of ten fresh human cadavers, between 6 4 and 93 years of age, were injected with Araldite CY 221 mixture, All cadavers were dissected and the posterior and anterior internal verte bral venous plexuses were studied in detail. The anterior part of the internal vertebral venous plexus is fairly constant, On the contrary, the posterior internal vertebral venous plexus showed a striking segme ntal and interindividual variability, In the thoracic area, two types of traversing veins are observed. Both types show a somewhat symmetric al ''inversed V'' configuration. No anatomical valves were observed, N evertheless, anterograde flushing (via the femoral veins) of the verte bral venous system appeared to proceed much faster than retrograde hus hing (via the superior vena cava), The classical picture of the intern al vertebral venous plexus appears a simplification of the actual situ ation. Especially in the posterior part, segmental and interindividual differences are prominent. The preferential direction of the flow dur ing hushing suggests the presence of functional valves, which are prob ably located in the thoracic part of the posterior internal vertebral venous plexus, resulting from the typical shape of the veins in this a rea, This might explain the difficulties with imaging of the posterior part of the internal vertebral venous plexus in vitro as well as in v ivo, Further study is needed to determine whether the configuration of the posterior internal vertebral venous plexus in younger individuals is different, compared with the presently studied aged subjects. (C) 1997 Wiley-Liss, Inc.