Term
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Definition
| By when does the neural plate develop |
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Term
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Definition
| What develops into the CNS? |
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Term
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Definition
| the neural plate gives rise to what? |
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Term
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Definition
| what forms the spine and the brain? |
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Term
- prosencephalon (forebrain)
- mesencephalon (midbrain)
- rhombencephalon (hindbrain)
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Definition
| the brain is initially what 3 vesicles? |
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Term
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Definition
| rhombencephalon is visualized when? |
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Term
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Definition
| neural function begins when? |
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Term
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Definition
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Term
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Definition
| most common neural tube defect |
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Term
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Definition
| higher prevalence of anencephaly where? |
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Term
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Definition
| anencephaly happens more often in which sex? |
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Term
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Definition
| absence of brain; result of failure of closure of the neural tube at the cranial end |
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Term
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Definition
| anencephaly has high levels of what?why? |
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Term
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Definition
| when can anencephaly be detected? |
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Term
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Definition
| froglike appearance, bulging of fetal orbits is associated with what? |
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Term
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Definition
| absence of the cranial bones with the presence of complete, although abnormal development of the cerebral hemispheres |
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Term
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Definition
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Term
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Definition
| this leads to anencephaly as the brain regresses due to exposure to amniotic fluid |
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Term
- presence of brain tissue without cranial vault
- Disorganization of brain tissue
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Definition
| sonographic features of acrania? |
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Term
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Definition
| neural tube defect; meninges alone or meninges and brain herniate through a defect in the calvarium |
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Term
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Definition
| upper part of the brain, surrounds cranium |
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Term
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Definition
| membranes that protect the CNS; contains the dura mater archnoid mater, and pia mater |
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Term
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Definition
| term used to describe herniation of the meninges and brain through the defect |
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Term
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Definition
| describes the herniation of only meninges |
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Term
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Definition
| sonographically appears as an extracranial mass, bony defect in the skull, and ventriculomegaly |
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Term
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Definition
| encompases a wide range of vertebral defects; failure of nueral tube closure; miniges and neural elements may protrude |
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Term
| lumbar and sacral regions |
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Definition
| spina bifida most commonly occurs along where? |
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Term
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Definition
| when covered with skin or hair, spina bifida is referred to as what? |
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Term
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Definition
| protrusion of the meninges only |
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Term
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Definition
| protrusion of meninges and neural elements; tends to be large; more common |
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Term
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Definition
| banana shape cerebellum due to the pulling of the exposed neural elements is associated with? |
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Term
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Definition
| scalloping of the frontal bones making the lemon sign is associated with? |
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Term
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Definition
| splaying of posterior ossification centers of the spine froming "U" instead of "V" is associated with? |
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Term
| dandy walker malformation |
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Definition
| agnesis or hypoplasia of the cerebellar vermis with resulting dilation on the fourth ventricle |
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Term
| dandy walker malformation |
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Definition
| result of abnormal embryogenesis of the roof of the fourth ventricle |
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Term
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Definition
| thought for dandy walker malformation to occur before when? |
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Term
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Definition
| most common ultrasound finding with dandy walker malformation? |
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Term
- posterior fossa cyst
- splaying of the cerebellar hemispheres
- enlarged cisterna magna caused by the cerebellar vermis anomaly and posterior fossa cyst
- ventriculomegaly
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Definition
| ultrasound findings of dandy walker? |
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Term
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Definition
results from abnormal development of the prosencephalon(forebrain)
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Term
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Definition
| holoprosencephaly is associated with what chromosomal anomaly? |
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Term
- alobar (most severe)
- semilobar
- lobar (least severe)
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Definition
| what are the 3 forms of holoprosencephaly? |
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Term
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Definition
- small brain tissue
- fusion of thalamus
- absence of:
- interhemispheric fissue
- cavum septum pellucidum
- corpus callosum
- optic tracts
- olfactory bulbe
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Term
| semilobar holoprosencephaly |
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Definition
- singular ventricle
- partial or complete fusion of the thalamus
- absent corpus callosum
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Term
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Definition
| may appear normal but cavum septum pelludicum with still be absent |
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Term
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Definition
| what connects the cerebral hemispheres |
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Term
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Definition
| aids in learning and memory |
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Term
| agenesis of the corpus callosum |
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Definition
Sonographic findings of what?
- absence of corpus callosum
- enlarged lateral ventricles
- absence of cavum septum pelucidum
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Term
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Definition
| results from obstruction, atresia or stenosis of the aqeduct of sylvius causing ventriculomegaly |
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Term
| third and fourth ventricle |
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Definition
| the aqueduct of sylvius connects what? |
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Term
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Definition
ultrasound findings of what?
- ventricular enlargement of lateral ventricles
- third ventricular dilation
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Term
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Definition
| rare arteriovenous malformation |
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Term
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Definition
ultrasound findings of what?
- cystic space tht may be irregular in shape and is located midline and posterosuperior to the third ventricle
- turbulent flow with doppler
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Term
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Definition
| round or ovoid anechoic structures within the choroid plexus; common |
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Term
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Definition
| choroid plexus cyst often resolve when? |
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Term
| aneuploidy; most commonly trisomies 18 & 21 |
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Definition
| choroid plexus cyst have been identified in associtation with? |
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Term
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Definition
destruction of the cerebral hemispheres by occlusion of the internal carotid arteries; brain parenchyma is destroyed and is replaced by cerebrospinal fluid
poor prognosis |
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Term
congenital infection of ischemia:
- cytomegalovirus(CMV) and toxoplasmosis
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Definition
| etiology of hydranencephaly inloves what? |
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Term
| severe hydrocephaly, presence of an intact falx and surrounding rim of brain parenchyma may help differentiate |
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Definition
| hydranencephaly may be confused with what? |
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Term
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Definition
Ultrasound findings of what?
- absence of normal brain tissue with almost complete replacement by cerebrosplinal fluid
- absent or partially absent falx
- presence of the midbrain, and cerebellum
- choriod plexus may be identidfied
- macrocephaly
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Term
hydrocephalus
(ventriculomegaly) |
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Definition
dilation of the ventricles within the brain; enlargement of the ventricles occurs with obtruction of cerebrospinal fluid flow
high mortality |
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Term
hydrocephalus
(ventriculomegaly) |
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Definition
ultrasound findings of what?
- lateral ventricular enlargement exceeding 10mm
- dangling choroid sign
- possible dilation of the third and fourth ventricles
- fetal head enlargement
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Term
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Definition
| abnormality small head that falls 2 standard deviations below the mean; more commonly caused by an associated anomaly |
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Term
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Definition
| condition associated with anencephaly in chich there is complete or partial absence of the cranial bones |
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Term
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Definition
| most severe form of holoprosencephaly characterized by a single common ventricle and malformed brain; orbital anomalies range from fused orbites to hypotelorism, with frequent nasal anomalies and clefting of the lip and palate |
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Term
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Definition
| neural tube defect characterized by te lack of developmetn of the cerebral and cerebellar hemispheres and cranial vault; this abnormality is incompatible with life |
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Term
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Definition
| an abnormality or congenital malformation |
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Term
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Definition
| form of holoprosencephaly characterized by a common ventricle, hypotelorism, an a nose with a single nostril |
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Term
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Definition
| sever form of holoprosencephaly characterized by a common ventricle, fusion of the orbits with one or two eyes present, and a proboscis |
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Term
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Definition
| an increase in size of jugular lymphatic sacs because of abnormal development |
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Term
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Definition
| a range of abnormalities from abnormal cleavage of the forebrain |
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Term
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Definition
| congenital absence of the cerebral hemisperes because of an occlusion of the carotid arteries; midbrain structures are present, and fluid replaces cerebral tissue |
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Term
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Definition
| ventriculomegaly in the neonate; abnormal accumulation of cerebrospinal fluid within the cerebral ventricles, resulting in compression and frequently destruction of brain tissue |
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Term
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Definition
| enlargement of the fetal cranium as a result of ventriculomegaly |
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Term
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Definition
| open spinal defect characterized by protrusion of spinal meninges |
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Term
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Definition
| open spinal defect characterized by protrusion of meninges and spinal cord through the defect, usually within a meningeal sac |
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Term
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Definition
| neural tube defect of the spine in which the dorsal vertebrae fail to fuse together, allowing the protrusion of meinges and/or spinal cord through the defect; two types exist |
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Term
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Definition
| closed defect of the spine without protrusion of meninges or spinal cord; alpha-fetoprotein analysis will not defect these lesions |
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Term
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Definition
| abnormal accumulation of cerebrospinal fluid within the cerebral ventricles resulting in dilation of the ventrcles; compression of developing brain tissue and brain damage may result; commonly associated with additional fetal anomalies |
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