Embryology & Early Development
Neural tube
The neural tube is the early embryonic structure that develops into the brain and spinal cord.
In short: Neural tube
- Encephalocele results when the neural tube does not close completely.
- It forms and closes very early in pregnancy.
- Its head end becomes the brain.
- Its closure is a coordinated, multi-step process.
What it is
It is the embryo's precursor to the entire central nervous system, forming early in pregnancy and closing in a coordinated sequence. Its head end develops into the brain, and its lower end into the spinal cord.
Understanding Neural tube
Encephalocele is a neural tube defect: when the cranial (head) end does not close fully, brain and membranes can later protrude through the resulting skull opening. The neural tube normally closes around the third to fourth week of pregnancy — often before a pregnancy is confirmed — which is why prevention efforts focus on the time around conception.
Why it matters
Understanding the neural tube explains the origin and timing of encephalocele, and why prevention (such as folic acid) targets the earliest weeks of pregnancy, before many people know they are pregnant.
Common questions
What does the neural tube become?
The brain and spinal cord.
When does it close?
Around the third to fourth week of pregnancy.
What happens if it doesn't close?
A neural tube defect such as encephalocele can result.
Bottom line
The neural tube becomes the brain and spinal cord, and its incomplete closure causes encephalocele.
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