Jugular vein, He is closer

The no-brainer question: How 1444 years ago, the Prophet Muhammad PBUH knew that the jugular vein is the closest vein to human?

The jugular veins are veins that take deoxygenated blood from the head back to the heart via the superior vena cava. The closest and most influential vein to the human body with many tasks. Today science is reconfirming this phenomena.

A verse:
Indeed, it is We, Who created humankind and fully know what their souls whisper to them, and We are closer to them than their jugular vein!
Quran: Kaf, The Letter Kaf; 50, 16.

Reflection: The jugular veins are major blood vessels that stretch from our head to our upper chest. —Veins of the head, neck and the heart with major tasks. If the blood stops jugular vein will not produce ‘’whispering’’ or any kind of reaction. There are 34 major veins. The jugular vein is the closest to the human body, but Allah is closer to us, than the jugular vein. Again another verse ahead of it’s time from the Quran.
That was said One Thousand Four Hundred and Forty Four years ago!