Anatomy General 442837c8 All of the following statements about Diploic veins are true, except? A Develop around 8th week of gestation B These have no valves (valveless) C Present in cranial bones D Have a thin wall lined by a single layer of endothelium High-Yield Explanation Diploic veins develop after bih and are not visible before 3 years of life. They fully develop only by 15 years of age.