<prompt> The marked structure close at which day of in-utero development JIPMER May 20197122530  <response>: - The picture is showing dorsal surface of fetus, having neural tube - have 2 openings anterior neuropore cranially - forms brain; posterior neuropore caudally - forms spinal cord - On dorsal surface of fetus- Notochord axial mesoderm stimulate overlying ectoderm to form Neural plate ectoderm which becomes Neural groove Detaches from dorsal surface, fuses at cervical region proceed Caudally cranially forming neural tube Surface ectoderm in periphery come to midline fuse together forming skin epithelium covering neural tissue Neural Crest Cells at periphery detach from dorsal surface to from Peripheral nervous system - Neural tube - will have 2 opening, which closes during course of development - Non closure leads to Open Neural Tube Defects. 1. Towards head - Cranialanterior neuropore - closes form brain by days Non closure of anterior neuropore leads to Anencephaly Leading to open brain skull cap Small degenerated brain is present.These fetus doesnt have swallow reflex resulting in polyhydramnios more Amniotic Fluid 2. Towards tail - CaudalPosterior neuropore - closes form spinal cord by day-28 Non-closure of posterior neuropore leads to Rachischisis Spinal cord veebra are open open veebra - spinal bifida Skin is also open CSF keep leaking outside Lady with fetus of open neural tube defects will have increased levels of ALPHA FETO-PROTEIN ACETYLCHOLINESTARASE enzyme Mother with polyhydramnios - check for AFP - If high check for AchE - if high do USG It may be a case of Anencephaly Rachischisis - Open neural tube defects can be prevented by giving prophylactic Folic acid supplements Dose - 400ugday - Antenatal as well as postnatal throughout the pregnancy - Both anencephaly rachischisis come together forming craniorachischisis. Skin remains at periphery; veebra are open veebra spines are not fused resulting in spina bifida Spinal cord is open CSF is leaking out. A - Craniorachischisis B - Anencephaly 