The Fetal Cranium
Ventriculomegaly is defined as lateral ventricular enlargement measuring greater than ____ mm.
10
A condition in which a complete or partial absence of the cranial bones is demonstrated is which one of the following?
Acrania
absence of the cranial boned with the presence of complete, although abnormal development of the cerebral hemispheres
Acrania (exencephaly)
The absence of the cavum septi pellucidi is a distinguishing characteristic of agenesis of the corpus callosum.
Agenesis of corpus callosum
a fibrous tract that connects the cerebral hemispheres and aids in learning and memory
Agenesis of the Corpus Callosum
Most severe form of holoprosencephaly
Alobar
Which one of the following is the most severe form of holoprosencephaly, which is characterized by a single common ventricle and malformed brain? Orbital anomalies range from fused orbits to hypotelorism, with frequent nasal anomalies and clefting of the lip and palate.
Alobar
singular monoventricle brain tissue that is small and may have a cup/ball like configuration, fusion of the thalamus, and absence of the interhemispheric fissure, cavum septum pellucidum, corpus callosum
Alobar
A vein of Galen malformation is which one of the following abnormalities?
An aneurysm of the Galen vein, a rare arteriovenous malformation, a sporadic event
Most common neural tube defect
Anencephaly
Which one of the following abnormalities is the most common open neural tube defect?
Anencephaly
Which one of the following neural tube defects is characterized by a lack of development of the cerebral hemispheres and cranial vault and is an abnormality that is incompatible with life?
Anencephaly
absence of the brain caused by failure of closure of the neural tube at the cranial end, absence of cranial vault, and complete or partial absence of the forebrain
Anencephaly
Which one of the following statements about anencephaly is incorrect?
Anencephaly has a male prevalence is incorrect; but it is a lethal disorder, is caused by the failure of closure of the neural tube at the cranial end
obstruction, atresia, or stenosis of the aqueduct of Sylvius causing ventriculomegaly aqueduct of sylvius connects the 3rd and 4th ventricles
Aqueductal Stenosis
presents with hydrocephalus caused by the cerebellar vermis which becomes displaced into the cervical canal; this changes the shape of the cerebellum
Arnold-Chiari (type II) malformation
Which of the following signs are characteristics of the Arnold-Chiari malformation?
Banana and lemon shaped
The ______ and ______ make up the central nervous system.
Brain and spine
neural tube defect in which the meninges alone or the meninges and brain herniate through a defect in the calvarium
Cephalocele
round or ovoid anechoic structures found within the choroid plexus
Choroid Plexus Cysts
obstruction may be outside of the ventricular system; such as with an arachnoid cyst
Communicating hydrocephalus
herniation of only the meninges
Cranial Meningocele
agenesis or hypoplasia of the cerebellar vermis with resulting dilation on the 4th ventricle and enlargement of the posterior fossa
Dandy-Walker Malformation
Which one of the following anomalies is characterized by the presence of a posterior fossa cysts and a splaying of the cerebellar hemispheres?
Dandy-Walker malformation
Which one of the following central nervous anomalies demonstrates splaying of the cerebellar hemispheres on ultrasound?
Dandy-Walker malformation
a range of complete to partial absence of the callosal fibers that cross the midline, forming a connection between the two hemispheres
Dysgenesis of the corpus callosum
Which one of the following defects is associated with Meckel-Gruber syndrome?
Encephalocele
Which one of the following terms is used to describe the herniation of the meninges and brain through a calvarium defect?
Encephalocele
herniation of the meninges and brain through the defect
Encephalocele
Which one of the following head anomalies is characterized by the presence of a single primitive ventricle?
Holoprosencephaly
abnormal cleavage of the prosencephalon (forebrain)
Holoprosencephaly
Which one of the following abnormalities is described as the congenital absence of the cerebral hemispheres resulting from an occlusion of the carotid arteries? The midbrain structures are present, and fluid replaces cerebral tissue.
Hydranencephaly
destruction of the cerebral hemispheres by occlusion of the internal carotid arteries Brain parenchyma is destroyed and replaced by cerebrospinal fluid
Hydranencephaly
Ventriculomegaly coupled with an enlargement of the fetal head is called which one of the following?
Hydrocephalus
occurs when ventriculomegaly is coupled with enlargement of the fetal head
Hydrocephalus
Facial anomalies in holoprosencephaly may represent all of the following except:
Hypertelorism
complete division of the ventricles is seen with a corpus callosum that may be normal, hypoplastic or absent, and the cavum septum pellucidum will be absent
Lobar
only protrusion of the meninges
Meningocele
An open spinal defect characterized by a protrusion of meninges and spinal cord through the defect, usually within a meningeal sac, is called which one of the following?
Meningomyelocele
the meninges and neural elements protrude through the defect
Meningomyelocele
abnormally small head that falls 2 standard deviations below the mean Occurs because brain reduced in size and may have inherited autosomal-dominant or autosomal- recessive pattern or from chromosomal anomaly
Microcephaly
enlargement of the ventricles occurs with obstruction of cerebrospinal fluid flow; this obstruction may be caused by a ventricular defect; such as aqueductal stenosis
Noncommunicating hydrocephalus
cysts filled with cerebrospinal fluid that communicate with the ventricular system or subarachnoid space
Porencephalic cysts (porencephaly)
very large and severe form of Meningomyelocele
Rachischisis
rare, clefts in the cerebral cortex
Schizencephaly
singular ventricular cavity with partial formation of the occipital horns, partial or complete fusion of the thalamus, absent corpus callosum, cavum septum pellucidum
Semilobar
vertebral defects that result from failure of neural tube closure, meninges & neural elements may protrude through this defect (means there is a cleft or opening in the spine)
Spina Bifida
when covered with skin or hair
Spina Bifida Occulta
Meningomyelocele is the most severe form of spina bifida.
True
arteriovenous malformation; Vein will be enlarged and will communicate with normal appearing arteries Sporadic event, male predominance, isolated anomaly Associated with cystic hygroma, congenital heart defects, hydrops
Vein of Galen Aneurysm
dilation of the ventricles within the brain
Ventriculomegaly (hydrocephalus)
