#neural tube defects – @biomedicalephemera on Tumblr

Craniorachischisis totalis

This open neural tube defect occurs very early in pregnancy, like all deformities and malformations of the neural tube.

I won’t get into the (actually very interesting, if complicated) specifics of the notochord and neural plates and the gene signaling going on, but around the third week of development a groove forms down the back of the embryo. This is called the neural groove, and it will form the canal that the spinal cord and spine will develop within. One of the most critical phases of development is the closure of that grove to form a tube, and much can go wrong.

Though an embryo may have such a malformation that they’re unable to sustain life independently, the genes and cells in other parts of the body don’t know that, and since they continue to receive blood and nutriment from the mother, they continue doing their thing and forming other structures. That’s how such a catastrophic defect from so early on can end up at this stage - fully formed except for the critical neural regions.

Manual of Pathology. W. M. Late Coplin, 1905.

#pathology #fetus #pregnancy #anencephaly #death #infant #developmental biology #1900s #1905 #W. M. Late Coplin #neural tube defects

biomedicalephemera

8 mm long and 10 mm long embryos with spina bifida

To get an idea how long that is, a pinhead is appx 1 mm across. One of those ubiquitous tiny red ants is 5 mm long, on average.

You can see here that the neural tube is created VERY early on pregnancy, which is why folic acid (critical to the cell signaling which closes the neural groove) is recommended for all women of childbearing age - this stage of pregnancy is often before the woman even knows she's pregnant, and if the pregnancy is carried to term, the lack of a single vitamin can lead to lifelong ramifications for the offspring.

For those who are into embryology/developmental biology: You can see the dorsal differences between Carnegie stages 15 and 16 if you look at these two embryos. The caudal neural pore has not yet attempted to close at all in the smaller of the two, and there are also only 3 pharyngeal arches clearly visible. In the larger of the embryos, a telling factor of which stage it's in is that you can clearly differentiate the thigh, leg, and foot parts of the hind limb buds.

A Study of the Causes Underlying the Origin of Human Monsters. Franklin P. Mall, 1908.

#developmental biology #embryo #spina bifida #neural tube defects #pregnancy #gestation #anatomy #dissection #monster #pathology #1900s #1908 #Franklin P. Mall #embryology

biomedicalephemera

Craniorachischisis totalis

This open neural tube defect occurs very early in pregnancy, like all deformities and malformations of the neural tube.

I won't get into the (actually very interesting, if complicated) specifics of the notochord and neural plates and the gene signaling going on, but around the third week of development a groove forms down the back of the embryo. This is called the neural groove, and it will form the canal that the spinal cord and spine will develop within. One of the most critical phases of development is the closure of that grove to form a tube, and much can go wrong.

Though an embryo may have such a malformation that they're unable to sustain life independently, the genes and cells in other parts of the body don't know that, and since they continue to receive blood and nutriment from the mother, they continue doing their thing and forming other structures. That's how such a catastrophic defect from so early on can end up at this stage - fully formed except for the critical neural regions.

Manual of Pathology. W. M. Late Coplin, 1905.

#pathology #fetus #pregnancy #anencephaly #death #infant #developmental biology #1900s #1905 #W. M. Late Coplin #neural tube defects