The variability and morphometry of the brachiocephalic trunk in human foetuses.

In prenatal and pediatric cardiovascular surgery knowledge of the various arrangements of the aortic arch and its branches as well as the normative data are essential. The variability and morphometric features of the brachiocephalic trunk in 131 human foetuses (65 male, 66 female) ranging from 15 to 34 weeks of gestation were studied by means of anatomical, digital and statistical methods. In all the foetuses examined the left aortic arches were found to have three different arrangements. In 74.05% of cases the usual pattern of the aortic arch with its three main branches were observed. A common origin of the brachiocephalic trunk and left common carotid artery occurred in 20.61% of individuals. In 5.34% of cases the left vertebral artery was an additional vessel and arose from the aortic arch between the left common carotid and subclavian arteries. No significant gender differences were found with respect to the brachiocephalic trunk (p > or = 0.05). The developmental increase in length (r1 = 0.78) and diameter (r2 = 0.83) correlated with a linear function but the increase in volume in relation to age corresponded to a quadratic function (r3 = 0.73). Our results show the largest increases in the brachiocephalic trunk according to the following parameters: the length - between the 4(th) and 5(th), and 7(th) and 8(th) months, diameter - between the 8(th) and 9(th) months and volume - between the 4(th) and 5(th), and 7(th) and 9(th) months of gestation (p < or = 0.01). The present study constructs a normal range for the morphometric features of the foetal brachiocephalic trunk.