Ob-Gyn Fetal Neural Axis (wkbk)
a ventricle is considered dilated when its diameter exceeds _____
10mm
Semilobar holoprosencephaly
A single ventricular cavity with partial formation of the occipital horns, partial or complete fusion of the thalamus, a rudimentary falx and interhemispheric fissure , and a absent corpus callosum, Cavum septum Pellucidum, and olfactory bulbs.
Fetuses with *myelomeningoceles* often present with cranial defects associated with ____. which is 90% of patients
Chiari type 2
Alobar holoprosencephaly
a monoventricle brain tissue that is small and may have a cup, ball, or pancake configuration fusion of thalamus absence of the interhemispheric fissure. cavum speti pellucidi, corpus callosum, optic tracts, and olfactory bulbs
ventriculomegaly
abnormal accumulation of cerebrospinal fluid within the cerebral ventricles-dilation of the ventricles; compression of the developing brain tissue and brain damage may result; commonly associated with additional fetal anomalies
Sonographic features of anencephaly
absence of the brain and cranial vault rudimentary brain tissue characterized as the cerebrovasculosa budging fetal orbits (frog like appearance)
sonographic features of agenesis of the corpus callosum
absence of the corpus callosum elevation and dilation of the third ventricle widely separated lateral ventricle frontal bones with medial indentation of the medial walls dilated occipital borns giving lateral ventricles a teardrop shape absnce of the cavum septi pellucidi
________ _______ results from obstruction, atresia, or stenosis of the aqueduct of sylvius, causing ventriculomegaly
aqueductal stenosis
a neural tube defect in which the meninges and brain herniate through a defect in the calvarium
cephalocele
spina bifida occulta
closed defect of the spine without protrusion of meninges or spinal cord
cyclopia
common ventricle, fusion of orbits with one or 2 eyes present, and a proboscis severe form of holoprosencephaly
acrania
complete or partial absence of the cranial bones assoc. with anencephaly
a fibrous tract that connects the cerebral hemispheres and aids in learning and memory
corpus callosum
macrocephaly
enlargement of the fetal cranium as a result of ventriculomegaly
anencephaly
failure of closure of the neural tube at cranial end
Cephalic neural plate develops into ______, and the caudal end forms the ______.
forebrain spinal cord
Cebocephaly
form of holoprosencephaly characterized by a common ventricle, hypotelorism, and a nose with a single nostril
cranial meningocele
herniation of only meninges
encephalocele
herniation of the meninges and brain through defect
cystic hygroma
increase in size of the jugular lymphatic sacs caused by abnormal development
almost complete division of the venticles is seen with a corpus callosum that may be normal, hypoplastic, or absent, although the cavum septi pellucidi will still be absent in _______
lobar holoprosencephaly
Alobar holoprosencephaly
most severe form of holoprosencephaly characterized by a single common ventricle and a malformed brain
anencephaly
neural tube defect characterized by lack of development of the cerebral and cerebellar hemispheres and cranial vault; ****incompatible with life
spina bifida
neural tube defect of the spine- dorsal vertebrae fail to fuse, allowing protrusion of meninges and or spinal cord through the defect
enlargement of the venticles occurs with _________ of cerebrospinal fluid flow
obstruction
fetal ventriculomegaly typically progresses from the ______ _____ into the temporal and then to the ________ ventricular horns
occipital frontal
meningomyelocele
open spinal defect- protrusion of meninges and spinal cord through defect, usually within a meningeal sac
meningocele
open spinal defect- protrusion of the spinal meninges
_______ or ______ cysts are cysts filled with cerebrospinal fluid
porencephaly or porencephalic cysts
sonographic features of Dandy Walker Malformation
post fossa cyst that can very considerably in size splaying of the cerebellar hemispheres as a result of complete/ partial agenesis of the cerebellar vermis an enlarged cisterna magna ventriculomegaly
Sonographic features of acrania
presence of brain tissue without the presence of a calvarium disorganization of the brain tissue prominent sulcal markings
The forebrain will develop into the _____, midbrain will become the _____, and the hindbrain will form the ________.
prosencephalon mesencephalon rhombencephalon
Holoprosencephaly
range of abnormalities resulting from abnormal cleavage of the forebrain
a rare disorder characterized by clefts in the cerebral cortex
schizencephaly
sonographic features of spina bifida
splaying of the post. ossification centers with a V or U configuration protrusion of a sac like structure that may be anechoic(meningocele) or contain neural elements(myelomeningocele) a cleft in the skin ventriculomegaly
hydrocephalus
ventriculomegaly in neonate abnormal accumulation of cerebrospinal fluid within the cerebral ventricles resulting in compression and frequently destruction of brain tissue