Abstract
In Japanese fetuses (30 cases) and adults (57 cases), the brachiocephalic vein and its venous roots were macroscopically observed. Synthetic latex rubber was injected into the veins of the fetuses through the superior vena cava. The observations were as follows:
I. The brachiocephalic veins
(1) The projectional position of the union of the brachiocephalic veins existed in the posterior position of the first sterno-costal joint in 70.0% of the fetuses.
(2) In 83.3% of the fetuses, the angles formed by the right and the left brachiocephalic veins varied from 91 to 110 degrees, which were rather obtuse compared with those of the adults.
(3) The left brachiocephalic vein was longer than the right one in all the fetal cases, and in 66.7% of them the left one was 1.6-2.0 times longer.
(4) The levels of the right and left venous angles were as follows: the left angles were higher than the right in 26.7% of the fetuses parallel in 40.0%, and lower in 33.3%, and in the adults, 38.6%, 35.1%, and 26.3%, respectively.
II. The venous roots
(1) The right internal thoracic veins flow into the anterior wall of the union part of the brachiocephalic veins in more than 80% of both the fetal and adult cases and the left internal thoracic veins flow in most cases into the inferior wall of the left brachiocephalic veins.
(2) Most of the inferior thyroid veins flow into the superior wall of the left brachiocepahlic vein or into the union part of the right and left brachiocephalic veins, in both the fetuses and adults. They have anastomosis with thymic veins in 90% of the cases.
(3) The thymic veins mostly flow into the inferior or anterior wall of the left brachiocephalic vein in both the fetuses and adults.
(4) Most of the right and left vertebral veins flow respectively into the right and left posterior wall of the venous angles.
