Superior vena cava is derived from:

Ans. C Cardinal veinRef; hangman's essesntial medical Embroyology pg. 57# During early embryonic development (through 4th week), paired cardinal veins drain the body. Anterior cardinal veins drain the head and upper limb buds, while posterior cardinal veins drain the body. Both the anterior and posterior veins on each side unite at the common cardinal veins that flow into the sinus venosus and ultimately into the common atrium (Image).# Anterior cardinal veins are retained. An anastomosis between the two forms the left brachiocephalic vein, and anterior segments from both form the jugular system for the head and neck (Image).# Most of the posterior segment on the left disappears except for that forming the left superior intercostal vein, whereas the right posterior segment forms the superior vena cava.Extra mileDefects of SVC Development* Double inferior vena cava occurs when the left supracardinal vein persists, thereby forming an additional inferior vena cava below the level of the kidneys.* Left superior vena cava occurs when the left anterior cardinal vein persists, forming a superior vena cava on the left side. The right anterior cardinal vein abnormally regresses.* Double superior vena cava occurs when the left anterior cardinal vein persists, forming a superior vena cava on the left side. The right anterior cardinal vein also forms a superior vena cava on the right side.