This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
All of the following are true about diploic vein except - 
Select and explain. 
A. Lined by single layer of endothelium supported by elastic tissue, B. Present in cranial bones, C. Valveless / thin walled, D. Develop by 8th week of IUL
D: Develop by 8th week of IUL
Answer: D: Develop by 8th week of IUL 
Explanation: The skull is unilamellar at birth with out any diploe and diploic veins which start to develop at around 2 years after birth.


Characteristic features of the diploic vein are:-


Absent at birth starts appearing around 2 years of age, appears at 4th year, and maximally differentiated by the 35th year when these are quite prominent radiologically.
Present in the diploe of the cranial vault. The major diploic veins are 1) Frontal, 2) Occipital, 3) Anterior and posterior temporal (parietal).
Wall is very thin consisting of endothelium supported by some elastic tissue.
Are valveless, as are other intracranial veins.