The presence of persistent left superior vena cava (PLSCV) is a congenital venous anomaly, due to regression failure of left anterior cardinal vein
at eighth gestational week.
Anomalous accessory hemiazygos system with persistent cranial segment of posterior cardinal vein
- A case report.
It is formed between the sixth and eighth weeks of embryonic development via a series of anastomoses and regressions of the following primitive trunk veins: posterior cardinal veins
, subcardinal veins and supra cardinal veins
DISCUSSION: The thoracic embryonic venous system is composed of anterior cardinal veins
which drain the cephalic part of the embryo and posterior cardinal veins
which drain the caudal part of embryo.
the primitive maxillary vein and the ventral pharyngeal vein which drain the rapidly growing mandibular and the hyoid arches into the common cardinal vein
Based on its lateral position, it is probably the remnant of left posterior cardinal vein
and not the supra-cardinal vein as the former is ventrolateral to the latter during development.
The venous system develops from three bilaterally symmetrical sets of veins in the embryo: the cardinal veins
, the vitelline veins, and the left and right umbilical veins.