Abstract:
The purpose of this study was to examine the degree of contribution from the vertebrobasilar and carotid systems to the
origin of the PCA in fetal autopsy brains of last trimester of pregnancy and to compare with published data on the configuration of adult
and fetal brains in a population of Sri Lankan origin. Materials and Methods: The external diameter of the PcomA, pre-communicating
part (P1), and the post-communicating part (P2) of posterior cerebral artery (PCA) of 34 fetal brain in the last trimester of pregnancy (30
to 40 weeks of gestation) was measured using a stereomicroscope equipped with a micrometer calibrator. Results: The blood supply to
the occipital lobe mainly via the PCA was seen in 25 (59%) of fetal brains as compared to that in the literature 220 (93%) in adults brains
and the blood supply to the occipital lobe mainly via the internal carotid artery (ICA) was seen in 16 (34%) of fetal brains as compared
to 25 (7%) of adults brains (P < 0.0001), transitional configuration where the PcomA is equal in diameter to P1 segment of the PCA was
seen in 5 (7.4%) of fetal brains and 8 (2%) of adults brains. Conclusions: The present study reveals that from the newborn to the adult
there is shift from carotid system to the vertebrobasilar system, this justifies further studies on different racial and geographic regions
which may give a clearer picture about the cerebral hemodynamics from childhood to adult.
