Source:http://linkedlifedata.com/resource/umls/id/C1817622
GO: The formation of the neural tube by coalescence of mesenchymal cells followed by their conversion to epithelial cells to form a solid cord that subsequently hollows out (cavitates) to create a hollow tube. Secondary neurulation is the typical mechanism of formation of the neural tube posterior to the posterior neuropore in mammals. [GOC:ef, ISBN:0878932585]