Anatomical basis of catheterisation of the umbilical vein

Abstract

Following a previous study of the gross anatomical and histological features of the adult umbilical vein, a histological and radiological investigation has been made on post-mortem material, to determine the route taken by probes and catheters introduced into the hemisected vein, to obtain access to the portal system.Although a residual part of the original lumen persists, it is far too small in diameter (approximately 0.2 mm) to admit probes and catheters. The instruments traverse a loose inner zone (the 'apparent lumen') and form a false passage within it. This zone, which is formed postnatally, is paler and of softer consitency than the surrounding zones, but since it becomes more fibrous and contracted in later life, instrumentation could prove more difficult in the elderly.At the umbilical-portal junction, the probe is arrested by the diverging right wall of the terminal expansion of the left branch of the portal vein (the recessus umbilicalis). Local rupture of the inner part of the wall by probe pressure gives access to the portal system. Without prior probing, contrast medium injected locally into the apparent lumen does not reach the portal system.