Faulty formation of neural tube

 Faulty formation of neural tube

1.              The whole length of the neural tube remains unclosed. This results in the condition called posterior rachischisis.

2.              The neural tube remains open in the region of the brain. This results inanencephaly. Braintissue which is exposed brain tissue degenerates.

3.              Non-fusion of the neural tube is of necessity associated with non-closure of the cranium (craniumbifidum) or of the vertebral canal (spina bifida).

4.              The brain may be too small (microcephaly) or too large (macrocephaly).

5.              Parts of the nervous system may be absent.