Fetal neural axis

when should the neural tube form completely

between 3-4 weeks

what is anencephaly

lack of development of cerebrum, cerebellum, and cranium

what kind of defect is anencephaly

stand alone defect

What is cebocephaly

form of holoprosencephaly with a single nostril and no septum

what is hydranenceophaly

congenital absence of cerebrum due to occluded carotid arteries

what is meningocele

open spinal defect with protrusion of spinal meninges

what is meningomyelocele

open spinal defect with protrusion of meninges and spinal cord, along with the sac

what is spina bifida

neural tube defect in which vertebral arches fail to fuse

the forebrain develops into

prosencephalon

The midbrain develops into

mesencephalon

the hindbrain develops into

rhombencephalon

what two regions does the spinal cord develop from

alar plate and basal plate

what is the alar plate

sensory region of cord

what is basal plate

motor region of cord

at what week does neural function begin

6 weeks

At what months can embryo grip things

4-5 months

what is the most common neural tube defect

anencephaly

What is anencephaly

Absence of brain and cranial vault

when do they typically find anencephaly

2nd-3rd trimester

what is acrania

cerebral hemispheres are present but not normal

what is acrania also known as

exencephaly

when does acrania occur

beginning of 4th week

with acrania, what shape does the brain take on

bilobed (Mickey mouse)

what is cephalocele

meninges and or brain herniate in calvarium defect

what is encephalocele

term used to describe the herniation

what is cranial meningocele

meninges herniation only

what may you find with fluid when there is cephalocele

polyhydraminos

what is spina bifida

failure of neural tube to completely close

What is Arnold Chiari 2 malformation

banana shaped cerebellum which leads to obliteration of cisterna magna

what head shape does Arnold chiari 2 malformation take on

lemon shaped due to frontal bones

what is a known issue that can cause spina bifida

folic acid deficiency

what is dandy walker malformation

agenesis or Hypoplasia of cerebellar vermis

What is the normal measurement of the cisterna magna

<11

What does holoprosencephaly result from

abnormal cleavage of prosencephalon

what chromosomal anomaly is holoprosencephaly associated with

trisomy 18

what is the most severe form of holoprosencephaly

alobar

what is seen with alobar holoprosencephaly

a lot of fluid in the brain and mono ventricle

what is seen with semilobar holoprosencephaly

a little bit more brain tissue but wildly abnormal still

what other factors can contribute to holoprosencephaly

retinoids and alcohol

When does the corpus collosum begin development

12 weeks and is completed by 20 weeks

what does the corpus collosum aid in

learning and memory

what are the sonographic findings of corpus collosum agenesis

elevation and dilation of 3rd ventricle

what does the aqueduct of sylvius do

communication between the 3rd and 4th ventricle

what is aqueductal stenosis

obstruction, atresia, stenosis of aqueduct of sylvius

what are the sonographic signs associated with aqueductal stenosis

lateral ventricle enlargement

what is vein of Galen aneurysm

rare AVM in males mainly

what are the sonographic findings associated with vein of Galen aneurysm

cystic space posterior superior to 3rd ventricle

what are choroid plexus cysts associated with

either completely normal or trisomy 18

what weeks do CHP cysts resolve

22-26 weeks

what is prosencephalic cysts

cysts filled with CSF connecting to ventricular system or subarachnoid space

what is schizencephaly

clefts in cerebral cortex

what is hydranencephaly

destruction of cerebral hemispheres due to occlusion of carotid arteries

how to tell the difference between holoprosencephaly and hydranencephaly

look for facial defects

what is ventriculomegaly associated with

spina bifida

What defines microcephaly

abnormally small head < 2 standard deviation