Abnormal development of nervous system 8/7
1. what is key to nervous system abnormalities: timing
2. anencephaly: congenital deformity in which some or all of fetal brain is missing; primary neural tube defect
3. craniorachischisis: total failure of neural tube to close; brain and spinal cord dont form and skull and spine
are open
4. rule of 12 for lumbosacral myelomeningocele: above T12 - other organs are affected, this is
more common in females
5. encephalocele: herniation of neural tube through axial mesodermal defect
6. what might the cortex show in encephalocele: polymicrogyrial heterotopias
7. chiari type 2: herniation of the cerebellar vermis with downard displacement of brainstem
1/4
, 8. skull base in chiari type 2: shallow posterior fossa, wide foramen magnum
9. what is chiari type 2 often seen with: lumbosacral myelomeningocele!!
hydrocephalus
10. what is the process called that splits the brain into R and L side: induction
11. holoprosencephaly: disorder of forebrain induction -> commissures dont form
12. maternal causes of holoprosencephaly: diabetes
toxoplasmosis
syphilis
rubella
fetal alcohol syndrome
chemicals/toxins
13. inheritance of holoprosencephaly: some can be familial
50% of cases have chromosomal aberrations trisomy 13,18 and triploidy
14. what type of trisomy is holoprosencephaly most commonly seen in: trisomy 13
15. features of holoprosencphaly in the brain: single lateral ventricle
2/4
1. what is key to nervous system abnormalities: timing
2. anencephaly: congenital deformity in which some or all of fetal brain is missing; primary neural tube defect
3. craniorachischisis: total failure of neural tube to close; brain and spinal cord dont form and skull and spine
are open
4. rule of 12 for lumbosacral myelomeningocele: above T12 - other organs are affected, this is
more common in females
5. encephalocele: herniation of neural tube through axial mesodermal defect
6. what might the cortex show in encephalocele: polymicrogyrial heterotopias
7. chiari type 2: herniation of the cerebellar vermis with downard displacement of brainstem
1/4
, 8. skull base in chiari type 2: shallow posterior fossa, wide foramen magnum
9. what is chiari type 2 often seen with: lumbosacral myelomeningocele!!
hydrocephalus
10. what is the process called that splits the brain into R and L side: induction
11. holoprosencephaly: disorder of forebrain induction -> commissures dont form
12. maternal causes of holoprosencephaly: diabetes
toxoplasmosis
syphilis
rubella
fetal alcohol syndrome
chemicals/toxins
13. inheritance of holoprosencephaly: some can be familial
50% of cases have chromosomal aberrations trisomy 13,18 and triploidy
14. what type of trisomy is holoprosencephaly most commonly seen in: trisomy 13
15. features of holoprosencphaly in the brain: single lateral ventricle
2/4
