Closure of neural tube begins at which of the following level:

Ans. A. Cervical regionThe process of formation of neural tube is called neurulation. The neural tube is formed from the ectoderm overlying the notochord. The neuroectodermal cells proliferate to form a thick plate called neural plate. The margins of the neural plate get elevated (neural folds) as paraxial mesoderm proliferates on either side of the notochord. This leads to the formation of neural groove flanked by neural folds. The neural groove becomes deeper and neural folds move towards midline to fuse with each other to form a cylindrical neural tube. The fusion of neural folds (i.e., closure of neural tube) begins at the cervical region and gradually extends in cephalic and caudal directions.