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)