intervertebral foramen and two layers of the spinal meninges invaginate the nerve—arachnoid and dura—forming a "dural sleeve" which is the epineurium.
Kaynak: Epineurium

Embryologically , the defect is thought to occur around day 35 of gestation , when the vesicle fails to invaginate . Dysgenesis of the
Kaynak: Cystic eyeball

This is a type of mycorrhizal infection whereby the fungus in question invaginate s the cell membrane of a plant cell , and branches in
Kaynak: Arum type