Term
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Definition
| disturbances due to abnormal closure of the neural tube |
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Term
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Definition
| most common CNS malformation; most frequently occurs in lumbosacral area; related to folate deficiency in pregnancy |
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Term
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Definition
| protrusion of arachnoid and subarachnoid space through the bony defect - cystic protrusion |
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Term
| meningomyelocele (myelomeningocele) |
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Definition
| meningocele accompanied by a portion of the spinal cord and nerves |
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Term
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Definition
| open neural groove, blending of neural ectoderm and skin; serious neurologic consequences |
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Term
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Definition
| meninges come out and open to skin - can be infection, loss of barrier; surgically closed at birth |
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Term
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Definition
| clinically unimportant; not visible though individuals often have a little tuft of hair over region on back |
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Term
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Definition
| brain's analogue of meningomyelocele; usually found in the occipital region or posterior fossa |
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Term
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Definition
| brain's analogue of spina bifida aperta, absence of brain and calvarium at the anterior end of the neural tube; jumble of red area of disorganized neural tissue, meninges, choroid plexus and ependymal (area cerebrovasculosa), disruption occurs at ~28 days; cranial vault does not form, ears malformed, eyes often normal |
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Term
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Definition
| defective separation of the prosencephalon into two cerebral hemispheres, thus single prosencephalon; associated with severe midline facial defects; associated with trisomies 13 and 18; maternal ingestion of cyclopamin in animals; cleft lip/palate, abnormalities of limbs; very little gyral and sulcal formation |
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Term
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Definition
| loss of the olfactory bulbs and tracts; often associated with midline facial defects, such as cleft lip/palate |
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Term
| agenesis of the corpus callosum |
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Definition
| may accompany holoprosencephaly or be isoloated; not life threatening |
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Term
| porencephaly/hydranencephaly |
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Definition
| cavities in the brain due to tissue destruction or failure of formation |
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Term
| lissencephaly/agyria/pachygyria |
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Definition
| all refer to a lack of gyral folding and sulcus formation; have been attributed to specific genetic abnormalities, such as the gene encoding the microtubule-associated protein LIS-1; pachy = thickened; not enough neurons and not arranged in the right way |
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Term
| microgyria/polymicrogyria |
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Definition
| little tiny folds that mimic gyri; not real gyri, don't form right connections, jumbled, not enough layers; up branching of white matter into cortex; sometimes band of conspicuous white matter present - heterotopic cortex, gray matter does not migrate up, in wrong place |
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Term
| Arnold-Chiari malformation |
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Definition
1. elongation of the medulla and 4th ventricle
2. protrusion of the posterior portion of the cerebellar vermis through the foramen magnum, thus lying dorsal to the elongated medulla
3. flattening and "beaking" of the quadrigeminal plate
-almost always associated with spina bifida, typipcally with a lumbosacral meningomyelocele
-most develop hydrocephalus |
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Term
| Dandy-Walker malformation |
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Definition
| characterized by an enlarged posterior fossa; cerebellar vermis is absent or rudimentary, and in its place is a midline cyst lined by ependyma; cyst represents expanded 4th ventricle |
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Term
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Definition
| term used to describe neurologic deficits which are noted soon after birth and don't progress; no unifying neuropathologic correlate and may be caused by malformative or destructive lesions or may follow perinatal hypoxia/ischemia. Discrete and nonprogressive. |
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