The Fetal Head and Brain
The sonographic findings that describes the echogenic choroid plexus, hanging limp, and surrounded by CSF, within the dilated lateral ventricle is called?
"dangling choroid" sign
lissencephaly-
"smooth brain"; condition where there is little to no gyri or sulci within the cerebral cortex
Lissencephaly literally means
"smooth brain."
Maternal serum screening, combines what 3 laboratory values
(human chorionic gonadotropin) estriol, and maternal serum alpha-fetoprotein (MSAFP),
Spina bifida may result in a mass that protrudes from the spine. This mass can be referred to as
, meningocele or myelomeningocele,
anencephaly-
-a neural tube defect that is described as the absence of the cranium and cerebral hemispheres
cebocephaly-
-close-set eyes (hypotelorism) and a nose with a single nostril
The cerebellum grows at a rate of ___ ___ per week between ___ & ___ weeks and thus correlates agreeably with the gestational age of the fetus.
1 mm 14 and 21
3 SONOGRAPHIC FINDINGS OF ACRANIA/ ANENCEPHALY
1. Absent cranial vault 2. Some cerebral tissue may be present 3. "Froglike" facies or bulging eyes
3 SONOGRAPHIC APPEARANCE OF A CHOROID PLEXUS CYST
1. Anechoic, 2. round, 3. smooth-walled cyst located within the choroid plexus of the lateral ventricle
1. The Frontal bone is ____ portion of the skull 2. The Parietal bones is ____ portion of the skull 3. The Temporal bones is ____ portion of the skull 4. The Occipital bones is ____ portion of the skull 5. The Sphenoid bones is ____ portion of the skull 6. The Ethmoid bones is ____ portion of the skull
1. Anterior 2. Superior and lateral 3. Inferior and lateral 4. Posterior 5. Lateral 6. Anterior (between orbits)
3 SONOGRAPHIC FINDINGS OF VENTRICULOMEGALY
1. Atrium of the lateral ventricle measures >10 mm 2. Dangling choroid sign 3. Dilatation of any part of the ventricular system
3 SONOGRAPHIC FINDINGS OF AQUEDUCTAL STENOSIS
1. Atrium of the lateral ventricle measures >10 mm 2. Dangling choroid sign 3. Dilatation of the lateral ventricles and the third ventricle; the fourth ventricle remains normal
6 Facial Anomalies associated with Alobar Holoprosencephaly
1. Cyclopia 2. Hypotelorism 3. Proboscis 4. (Median) cleft lip 5. Anophthalmia 6. Cebocephaly
2 SONOGRAPHIC FINDINGS OF PORENCEPHALY
1. Cystic mass that communicates with the lateral ventricle 2. Most often unilateral
1 CLINICAL FINDINGS OF ARNOLD-CHIARI II MALFORMATION
1. Elevated MSAFP
1. CLINICAL FINDINGS OF ACRANIA/ANENCEPHALY
1. Elevated MSAFP
4 SONOGRAPHIC FINDINGS OF DANDY-WALKER MALFORMATION
1. Enlargement of the cisterna magna >10 mm in the anteroposterior dimension 2. Communication of the enlarged cisterna magna with a dilated fourth ventricle 3. Agenesis or hypoplasia of the cerebellar vermis 4. Varying degrees of ventriculomegaly
2 SONOGRAPHIC FINDINGS OF MEGA CISTERNA MAGNA
1. Enlargement of the cisterna magna >10 mm in the anteroposterior dimension 2. Normal cerebellum and fourth ventricle
3 SONOGRAPHIC FINDINGS OF SCHIZENCEPHALY
1. Fluid-filled clefts within the cerebrum 2. Agenesis of the CSP and corpus callosum (50% of the time) 3. Ventriculomegaly
4 SONOGRAPHIC FINDINGS OF HYDRANENCEPHALY
1. Fluid-filled cranium 2. Absent or partial absence of the falx cerebri 3. Maintained brain stem, basal ganglia, and per- haps the thalamus 4. No identifiable cerebral cortex
4 SONOGRAPHIC FINDINGS OF ALOBAR HOLOPROSENCEPHALY
1. Horseshoe-shaped monoventricle 2. Fused echogenic thalami 3. Absence of the CSP, interhemispheric fissure, falx cerebri, corpus callosum, and third ventricle 4. Normal cerebellum and brain stem
Fetal head shapes and associated anomalies Macrocephaly shape head is associated with what 5 anomalies
1. Hydrocephalus 2. Hydranencephaly 3. Intracranial tumors 4. Familial inheritance 5. Beckwith-Wiedemann syndrome
1 SONOGRAPHIC FINDINGS OF LISSENCEPHALY
1. Lack of sulci and gyri within the cerebrum
7 SONOGRAPHIC FINDINGS OF ARNOLD-CHIARI II MALFORMATION
1. Lemon sign-lemon-shaped cranium with flat- tened frontal bones 2. Banana sign-banana-shaped cerebellum 3. Obliterated cisterna magna 4. Colpocephaly 5. Enlarged massa intermedia 6. Hydrocephalus 7. Open spinal defect
What are the 4 Different types of cephaloceles
1. Meningocele 2. Encephalocele 3. Encephalomeningocele 4. Encephalomeningocystocele
3 SONOGRAPHIC FINDINGS OF CEPHALOCELES
1. Open cranial defect (typically posterior in location) 2. Small or obliterated cisterna magna 3. Complex or simple appearing mass protruding from the cranium
4 SONOGRAPHIC FINDINGS OF AGENESIS OF THE CORPUS CALLOSUM AND CAVUM SEPTUM PELLUCIDUM
1. Partial or complete absence of the corpus callosum and absence of the CSP (after 18 weeks) 2. "Sunburst" sign-radial arrangement of the sulci which produces a "spoke wheel" pattern 3. Colpocephaly-small frontal horns and en- larged occipital horns (teardrop-shaped lateral ventricles) 4. Elevated and dilated third ventricle
1 CLINICAL FINDINGS OF CEPHALOCELES
1. Possible elevation of MSAFP
Fetal head shapes and associated anomalies Microcephaly shape head is associated with what 5 anomalies
1. TORCH infections 2. Trisomy 13 3. trisomy 18 4. Meckel-Gruber syndrome 5. Fetal alcohol syndrome
Alobar holoprosencephaly is diagnosed when there is absence of what 5 important functions
1. corpus callosum, 2. CSP, 3. third ventricle, 4. interhemispheric fissure, and 5.;falx cerebri.
Locations of the fontanelles and the age when they close 1. Anterior or frontal Fontanelle Bordered by what 2 skull bones Close by Age? 2. Posterior or occipital Fontanelle Bordered by what 2 skull bones Close by Age? 3. Anterolateral or sphenoidal Fontanelle Bordered by what 2 skull bones Close by Age? 4. Posterolateral or mastoid Fontanelle Bordered by what 2 skull bones Close by Age?
1. frontal and parietal bones 18months 2. occipital and parietal bones 6 months 3. frontal, parietal, and sphenoid 2years old 4. mastoid and occipital bones 2 years old
The normal lateral ventricle does not typically measure more than ___ ___ at the level of the atrium..
10 mm
The depth of the cisterna magna should not measure more than ___ ___ or less than ___ ___ in the transcerebellar plane.
10 mm 2 mm
Suspicion of ventricular dilatation occurs when the atrial diameter measures more than
10 mm.
The biparietal diameter (BPD) measurement of the fetal head can be taken starting between ___ and ___ weeks
13 and 14 weeks.
the cerebellum of a 16-week fetus will measure approximately
16 mm.
The corpus callosum forms late in gestation, but should be completely intact between ___ and ___ weeks
18 and 20 weeks.
To claify as a Choroid Plexus Cysts it must measure more than
2 mm,
By ___ weeks, the neural plate, the structure that will form the central nervous system, has developed.
4.5
The Cerebral aqueduct (aqueduct of Sylvius), located between the third and fourth ventricles of the brain, may be narrowed, thus preventing the flow of CSF from the third to the fourth ventricle. Which causes?
AQUEDUCTAL STENOSIS
What is the most common neural tube defects.
Acrania
the absence of the cranial vault above the bony orbits is named
Acrania
is considered when there are no cerebral hemispheres present,
Anencephaly
What are the two most common neural defects
Anencephaly in spina bifida
What are the 2 most common neural defects,
Anencephaly spina bifida
Which anomaly can be confused with porencephaly.
Arachnoid cysts
What is the name of the reabsorption of CSF into the venous system.
Arachnoid granulation
Cisterna Magna Measurement of less than 2 mm is worrisome for what anoomally?
Arnold-Chiari II malformation.
What is a group of cranial abnormalities associated with the neural tube defect spina bifida.
Arnold-Chiari II or Chiari II malformation
The head circumference (HC) measurement taken and at the same level of the cranium as the obtained
BPD.
What is thr formula used to calculate the cephalic index
BPD/OFD × 100.
Different types of cephaloceles and their contents What contents are included with: Encephalomeningocele
Both meninges and brain tissue
Different types of cephaloceles and their contents What contents are included with: Encephalocele
Brain tissue only
protrusions of intracranial contents through a defect in the skull is called
Cephaloceles
Arnold-Chiari II also known as
Chiari II malformation
what should be suspected if the cisterna magna is not visualized.
Chiari II malformation
Fetal head shapes and associated anomalies: Lemon shape head is associated with what anomalies
Chiari Il malformation
If the cerebellar vermis is absent and the fourth ventricle is enlarged, then what must be suspected.
DandyWalker Malformation
What are the names of the 6 cranial bones
Frontal bone Parietal bones Temporal bones Occipital bone Sphenoid bone Ethmoid bone
What is the name that refers to the dilatation of the ventricular system caused by an increased volume of CSF, resulting in in creased intraventricular pressure.
Hydrocephalus
With hydranencephaly will the thalamus be seen? Will the cerebral cortex be seen?
Maybe No
What are the 3 Posterior Fossa Abnormality
Mega cisterna magna Dandy-Walker malformation Arnold-Chiari Il malformation
Different types of cephaloceles and their contents What contents are included with: Meningocele
Meninges only
Different types of cephaloceles and their contents What contents are included with: Encephalomeningocystocele
Meninges, brain tissue, and lateral ventricle
Does the cavum septum pellucidum communicate with the ventricle system?
No
What two measurments are used to obtain the corrected-BPD,
Occipitofrontal Diameter BPD
Holoprosencephaly is the failure of what
Prosencephalon(forebrain) to develop normally
dolichocephaly, also referred to as
Scaphocephaly
What is the name of the term that is associated with the development of fluid-filled clefts within the cerebrum.
Schizencephaly
Fetal head shapes and associated anomalies Cloverleaf shape head is associated with what anomalies
Thanatophoric dysplasia
What is the largest part of the brain.
The cerebrum
noncommunicating hydrocephalus-
The obstruction of cerebrospinal fluid from a source within of the ventricular system
Fetal head shapes and associated anomalies Strawberry shape head is associated with what anomalies
Trisomy 18
What is the most common cranial abnormality.
Ventriculomegaly
Holoprosencephaly alobar, the cortex can take on three basic. shapes resembling a
a "pancake," "cup," or "ball"
thalamus- Aka
a brain structure that allows communication between the senses; also performing many other functions
schizencephaly-
a cerebral malformation associated with the development of fluid-filled clefts
Patau syndrome- Aka
a chromosomal aberration in which there is a third chromosome 13; also referred to as trisomy 13
porencephaly-
a condition in which a cyst, most often caused by an intraparenchymal hemorrhage, communicates with a lateral ventricle
falx cerebri-
a double fold of dura mater located within midline of the brain
hydranencephaly-
a fatal condition in which the entire cerebrum is replaced by a large sac containing cerebro- spinal fluid
Meckel-Gruber syndrome-
a fetal syndrome associated with microcephaly, occipital encephalocele, polydactyly, and polycystic kidneys
triploidy-
a fetus that has three of every chromosome
suture (skull)-
a flexible, connective tissue that lies be- tween the cranial bones
exencephaly-
a form of acrania in which the entire cerebrum is located outside the skull
holoprosencephaly-
a group of brain abnormalities con- sisting of varying degrees of fusion of the lateral ventricles absence of the midline structures, and associated facial anomalies
Arnold-Chiari |l malformation-
a group of cranial abnormalities associated with spina bifida
spinal dysraphism-
a group of neural tube defects that describe some manifestation of incomplete closure of the snine
basal ganglia-
a group of nuclei within the brain that function in several ways, including information processing and emotional response
germinal matrix-
a group of thin-walled blood vessels and cells within the subependymal layer of the fetal brain responsible for brain cell migration during fetal development
Beckwith-Wiedemann syndrome-
a growth disorder syndrome synonymous with enlargement of several organs, including the skull, tongue, and liver
cavum septum pellucidum-
a normal midline brain struc- ture identified in the anterior portion of the brain between the frontal horns of the lateral ventricles
cistern-
a prominent space within the skull that contains cerebrospinal fluid; a cistern is created by the separation of the arachnoid membrane and pia mater
hypoxia-
a shortage of oxygen or decreased oxygen in the blood
dangling choroid sign-
a sonographic sign associated with ventriculomegaly when the choroid plexus is noted hanging freely within the dilated lateral ventricle
Dandy-Walker complex-
a spectrum of posterior fossa abnormalities that involves the cystic dilatation of the cis- terna magna and fourth ventricle
median cleft lip-
a subdivision within the middle of the lip
corpus callosum-
a thick band of white matter that provides communication between right and left halves of the brain
folate- Aka
a vitamin that has been shown to significantly reduce the likelihood of neural tube defects; also referred to as folic acid
The divisions of lateral ventricles, called the horns of the lateral ventricles, correlate with the
adjacent cranial bones.
The absence of all or part of the corpus callosum is referred to as
agenesis of the corpus callosum.
Which specific type of holoprosencephaly is the most severe form, often resulting in neonatal death.
alobar
There are three main types of holoprosencephaly: What are they?
alobar, semilobar, and lobar.
hydrops (fetal)-
an abnormal accumulation of fluid in at least two fetal body cavities
TORCH infections-
an acronym that stands for toxoplasmo simplex virus; this group of infections may be acquired by sis, other infections, rubella, cytomegalovirus, and herpes a woman during pregnancy
omphalocele-
an anterior abdominal wall defect where there is herniation of the fetal bowel and other abdominal organs into the base of the umbilical cord
subarachnoid space-
an area located between the arachnoid membrane and the pia mater
vein of Galen aneurysm-
an arteriovenous malformation that occurs within the fetal brain and is associated with congestive heart failure
dolichocephaly- Aka
an elongated, narrow head shape; may also be referred to as scaphocephaly
macrocephaly-
an enlarged head circumference
mega cisterna magna-
an enlargement of the cisterna magna as defined by a depth of more than 10 mm
dilatation-
an enlargement or expansion of a structure
Choroid plexus papillomas are found within the choroid plexus and produce
an increase in the production of CSF, which leads to ventriculomegaly.
craniosynostosis leads to
an irregular-shaped skull.
aperture(s)-
an opening in a structure
The cavum septum pellucidum will appear as an
anechoic "box-shaped" structure in the axial scan plane
On sonography, the cisterna magna appears as an
anechoic, fluid-filled space, posterior to the cerebellum,
The cavum septum pellucidum (CSP) is a midline brain structure located in the ____ portion of the brain between the
anterior frontal horns of the lateral ventricles.
The cerebral aqueduct aka
aqueduct of Sylvius
The third ventricle connects to the fourth ventricle inferiorly by tubelike structure what are the two names called?
aqueduct of Sylvius or the cerebral aqueduct.
What is the most common cause of hydrocephalus in utero.
aqueductal in utero.
the middle layer of the meninges
arachnoid membrane,
Arachnoid granulations, also referred to as
arachnoid villi,
What is the difference between Arachnoid cysts and porencephaly.
arachnoid will not communicate with the ventricular system.
Choroid plexus, which is mostly located within the ____ of the lateral ventricles,
atria
The BPD is obtained in the ____ plane at the level of the (3)
axial Cavum septum Pellucidum CSP, thalamus, and falx cerebri.
arachnoid cyst(s)-
benign cysts within the brain that do not communicate with the ventricular system
What is the name of a head shape is one that is considered round or short and wide,
brachycephalic
Holoprosencephaly is a midline brain anomaly that is associated with
brain aberrations also atypcal facial structures.
With hydranencephaly WHAT TWO STRUCTURES ARE maintained and surrounded by CSF
brain stem and basal ganglia
The anterior fontanel, when completely filled with bone, is referred to as the
bregma,
obstructive hydrocephalus is the
buildup of CSF within the ventricular system secondary to some type of obstruction.
The sonographic intracranial findings consistent with intrauterine infections are
calcifications around the ventricles and ventriculomegaly.
What is a useful tool for indicating the shape of the fetal head.
cephalic index
Cisterna Magna located between the
cerebellar vermis
Alobar holoprosencephaly the ____ and ____ ____ remain intact.
cerebellum brain stem
From the third ventricle, CSF travels to the fourth ventricle through the.
cerebral aqueduct
The greater part of CSF is produced by the cells of the
choroid plexus
Choroid plexus cysts are cysts located within the
choroid plexus of the lateral ventricles.
the mass of cells responsible for the production of cerebrospinal fluid (CSF) in the fetus is called
choroid plexus,
trisomy 13- Aka
chromosomal aberration in which there is a third chromosome 13; also referred to as Patau syndrome; often associated with holoprosencephaly
trisomy 18- Aka
chromosomal aberration in which there is a third chromosome 18; also referred to as Edwards syndrome
trisomy 21- Aka
chromosomal aberration in which there is a third chromosome 21; also referred to as Down syndrome
trisomy 8- Aka
chromosomal aberration in which there is a third chromosome 8; also referred to as Warkany syndrome 2
What are two main types of hydrocephalus,
communicating and noncommunicating.
corpus callosum, a thick band of tissue that provides what
communication between the right and left halves of the brain.
Dandy-Walker malformation The cerebellar vermis is either
completely absent or hypoplastic.
Several notable changes occur within the brain and skull with spina bifida. The cerebellum will become displaced inferiorly and posteriorly as a result of the cisterna magna is
completely obliterated.
What happens to the cisterna magna when arnold chiari is diagnosed
completely obliterated.
Dandy-Walker malformation-
congenital brain malformation in which there is enlargement of the cisterna magna, agenesis of the cerebellar vermis, and dilation the fourth ventricle
The cerebral hemispheres are linked in the midline by the
corpus callosum,
Premature fusion of the sutures is termed
craniosynostosis.
The ventricular system composed of four ventricles, whose primary function is to provide
cushioning for the brain
Porencephaly is a rare condition in which a
cyst communicates with the ventricular system.
Porencephaly can occur after the fetus has experienced hemorrhage within one or both of the cerebral hemispheres. As hemorrhage changes states, it will form into a
cystic cavity and will eventually communicate with the lateral ventricle of the affected side
Dandy-Walker complex. involves the
cystic dilatation of the cisterna magna and fourth ventricle.
What is the most common in utero infection,,
cytomegalovirus
The most common location of spina bifida is within the
distal lumbosacral region
A cephalic index of less than 75 denotes a _____ shape, whereas an index of more than 85 denotes a _____ shape.
dolichocephalic brachiocephalic
What is the name that denotes an elongated, narrow head shape
dolichocephaly,
The normal cerebellum is a ____-shaped or figure ____-shaped structure noted in the posterior cranium of the fetus.
dumbbell eight
The falx cerebri, is a double fold of?
dura mater,
the dense outermost layer of the meninges is the
dura mater.
The falx cerebri, a double fold of dura mater, is located within the interhemispheric fissure and can readily be noted on a fetal sonogram as an
echogenic linear formation coursing through the midline of the fetal brain
The skull consists of how many cranial bones
eight
neural tube-
embryologic formation that results from fusion of the two folded ends of the neural plate
Neural tube defects occur when the
embryonic neural tube fails to close.
The Dandy-Walker Malformation sonographic findings include an
enlarged cisterna magna that communicates with a distended fourth ventricle through a defect in the cerebellum
Hydranencephaly is a fatal condition in which the
entire cerebrum is replaced by a large sac containing CSF,
Each ventricle is lined by a membrane called the
ependyma.
absence of the cranial vault above the bony orbits and.denotes a normal amount of cerebral tissue is named
exencephaly.
With hydranencephaly, what may be partially or completely absent?
falx cerebri
The paired lateral ventricles are located on both sides of the
falx cerebri within the cerebral hemispheres.
Sonographically, the rhombencephalon may be noted within the
fetal cranium during the first trimester
Several notable changes occur within the brain and skull with spina bifida. The frontal bones become ____ and will vield a ____ shape to the cranium, which is referred to as the "____" sign, often referred to as?
flattened lemon lemon scalloping of the frontal bones
proboscis-
fleshy, tongue-like appendage that is typically located within the midline above the orbits in association with cyclopia and holoprosencephaly
Schizencephaly is described as
fluid-filled clefts within the cerebrum.
gyri-
folds in the cerebral cortex
Spaces that exist between the forming fetal bones are referred to as
fontanelles or "soft spots"
Another opening of the fourth ventricle, located in the midline, is the median aperture, which is also referred to as the.
foramen of Magendie
Each lateral ventricle communicates with the third ventricle in the midline of the brain at the
foramen of Monro, or the paired interventricular foramina.
What allows CSF to travel from the fourth ventricle to the subarachnoid space around the brain.
foramina of Luschka.
CSF moves from the lateral ventricles into the 3rd ventricle through the?
foramina of Monro.
The ventricular system is composed of how many bentricles
four ventricles,
Which ventricle is located anterior to the cerebellum
fourth ventricle
cyclopia-
fusion of the orbits
intracranial hemorrhage-
general term used to denote a hemorrhage within the cranium
Apert syndrome-
genetic disorder that includes cranio- synostosis, midline facial hypoplasia, and syndactyly
When measuring the lateral ventricle The calipers are placed at the level of the _____ of the choroid plexus.
glomus
interhemispheric fissure-
groove within the midline of the brain that divides the two cerebral hemispheres
sulci-
grooves within the brain
Teratomas contain tissues such as
hair. sebum, and fat
intraventricular hemorrhage-
hemorrhage located within the ventricles of the brain
Porencephaly can occur after the fetus has experienced.
hemorrhage within one or both of the cerebral hemispheres.
gastroschisis-
herniation of abdominal contents through a right-sided, periumbilical abdominal wall defect
meningocele-
herniation of the cranial or spinal meninges because of an open cranial or a spinal defect
The normal cerebral circulation typically yields a ___-impedance Doppler pattern, with _____ forward flow throughout the cardiac cycle.
high continuous
Trisomy 13, or Patau syndrome, is present in 50% to 70% of fetuses diagnosed with
holoprosencephaly.
Alobar holoprosencephaly There will also be evidence of a _____-shaped monoventricle. and the lobes of the ____ may be fused and echogenic in appearance
horseshoe thalamus
Fetal sutures may be noted during a routine sonographic examination as
hypoechoic spaces between the bones.
hypoplasia-
incomplete growth of a structure or an organ
Hydrocephalus caused by an
increased volume of CSF, resulting in in creased intraventricular pressure.
The Cavum Septum Pellucidum, located _____ to the corpus callosum,
inferior
CSF also flows _____ and around the spinal cord.
inferiorly
Several notable changes occur within the brain and skull with spina bifida. The cerebellum will become displaced ____ and ___ and appear curved in the presence of spina bifida, which is referred to as the "___" sign
inferiorly and posteriorly banana
The falx cerebri, a double fold of dura mater, is located within the
interhemispheric fissure
The cerebrum can be further divided into a right and left hemisphere by the
interhemispheric fissure.
Most often, the origin of intracranial hemorrhage, also referred to as _____ hemorrhage, is within the
intraventricular germinal matrix.
The atrium of the lateral ventricle is the optimal site for measuring the lateral ventricle, because
it is the first region where ventricular enlargement occurs.
when completely filled with bone, posterior fontanel is referred to as the
lambda.
sonographic findings associated with brain tumors are
macrocephaly and intracranial calcifications.
myelomeningocele-
mass that results from spina bifida that contains the spinal cord and the meninges.
the most common risk factor for fetal intrauterine intracranial hemorrhage is
maternal platelet disorders.
Once in the fourth ventricle, the CSF can exit either through the
median aperture or the lateral apertures.
Which aperture or opening allows CSF to pass from the fourth ventricle to the cisterna magna and subarachnoid space.
median aperture, of the 4th ventricle
When the Cisterna Magna Measures more than 10 mm is consistent with what 2 anomalies
mega cisterna magna and Dandy-Walker complex,
What are the protective tissues layers that cover the brain and the spinal cord.
meninges
The normal- to medium-sized skull is termed
mesocephalic.
Alpha-Fetoprotein (AFP) exits the fetus through an opening in the
neural tube (cranium or spine),
The neural plate will give rise to the
neural tube,
Lissencephaly is a condition in which there are
no gyri within the cerebral cortex.
arachnoid granulations-
nodular structures located along the falx cerebri that reabsorb cerebrospinal fluid into the venous system
The germinal matrix vessels are prone to rupture The hemorrhage can spread into the lateral ventricle, often leading to
noncommunicating hydrocephalus
mesocephalic-
normal head shape
noncommunicating hydrocephalus occurs when the
obstruction level is located within the ventricular system.
Communicating hydrocephalus is occurs when the
obstruction lies outside the ventricular system,
The HC can also be obtained by measuring the _____ _____ and taking an ___ ___ ____ diameter measurement at the level of the BPD.
occipitofrontal diameter (OFD) outer-to-outer
The cerebellar tonsils, are located where?
on the undersurface of the cerebellum
monoventricle-
one large ventricle within the brain asso- ciated with holoprosencephaly
Schizencephaly may be described as having an
open lip or closed lip,
The foramen magnum is the
opening in the base of the cranium through which the spinal cord travels.
BPD measurement is obtained from the
outer table of the proximal parietal bone to the inner table of the distal parietal bone.
cerebral peduncles-
paired structures located anterior to the cerebral aqueduct
The corpus callosum functionally provides a
pathway for communication between the hemispheres and is completely formed by 18 weeks.
With agenesis of the corpus callosum, the sulci tend to have a more ___ or___ arrangement, and often appear to have a _____ ____pattern.
perpendicular or radial spoke wheel
The innermost layer of the meninges is the
pia mater,
The cisterna magna, located in the
posterior fossa of the cranium,
The cerebellum is located in the
posterior fossa of the cranium.
Initially, the brain is divided into three primary vesicles What are they?
prosencephalon (fore-brain), mesencephalon (midbrain), and rhombencephalon (hindbrain)
Arachnoid granulations, also referred to as arachnoid villi, are responsible for the
reabsorption of CSF into the venous system.
hypotelorism-
reduced distance between the orbits
hydrocephalus-
refers to the dilatation of the ventricular system caused by an increased volume of cerebrospinal fluid, resulting in increased intraventricular pressure
corrected-BPD-
represents the biparietal diameter of a standard-shaped fetal head with the same cross-sectional area
The paired lateral ventricles are frequently referred to as ____ and ____ ventricles but may also be called the _____ and ____ ventricles.
right and left ventricles first and second
Dandy-Walker malformation is thought to be caused by a developmental abnormality in the
roof of the fourth ventricle.
brachycephalic-
round skull shape
The falx cerebri _____ the cerebral hemispheres, whereas the corpus callosum _____ the cerebral hemispheres and allows _____ between the two lobes.
separates connects communication
There are how many cerebral lobes:
six
microcephaly-
small head
A lipoma will appear as a
solid echogenic mass.
Fontanelles are often utilized as
sonographic windows during neurosonographic examinations to evaluate newborns for intracranial hemorrhage or suspected brain anomalies.
Screening for neural tube defects is achieved by a combination of what 3 screening tools?
sonography, amniocentesis, and/or maternal serum screening.
choroid plexus-
specialized cells within the ventricular system responsible for cerebrospinal fluid production
The cerebellar tonsils, are located on the undersurface of the cerebellum and become distorted with what two defects
spina bifida and Arnold-Chiari malformations.
The neural plate will give rise to the neural tube, which will become the
spine and the brain.
Spina bifida may result in a mass that protrudes from the
spine.
The normal cerebrum contains multiple
sulci and gyri.
Arachnoid granulations, also referred to as arachnoid villi, are responsible for the reabsorption of CSF into the venous system. This process occurs at the
superior sagittal sinus, located along the superior surface of the cerebrum within its midline.
eight cranial bones are connected by structures known as
sutures
The _____, a vital brain structure that has numerous functions, is a significant landmark for sonographers locate within the fetal brain
thalamus
colpocephaly-
the abnormal lateral ventricle shape in which there is a small frontal horn and enlarged occipital horn
aqueductal stenosis-
the abnormal narrowing of the cerebral aqueduct
acrania -
the absence of the cranial vault above the bony orbits
anophthalmia-
the absence of the eyels)
subependymal (layer)-
the area just beneath the ependymal lining the lateral ventricles
The brain can be divided into two main parts, What are they?
the cerebrum and the cerebellum.
agenesis of the corpus callosum-
the congenital absence of corpus callosum which may be partial or complete
meninges-
the coverings of the brain and spinal cord
dura mater-
the dense, fibrous outer layer of the meninges
cerebral aqueduct- AKA
the duct that connects the third ventricle of the brain to the fourth ventricle; also referred to as the aqueduct of Sylvius
neural plate-
the early embryologic structure that develops into the central nervous system
facies-
the features or appearance of the face
What are the six cerebral lobes:
the frontal lobe, two temporal lobes, two parietal lobes, and the occipital lobe.
parenchyma-
the functional part of an organ
The divisions of lateral ventricles, called
the horns of the lateral ventricles,
pia mater-
the innermost layer of the meninges
cisterna magna-
the largest cistern in the skull; located in the posterior portion of the skull
glomus (of choroid plexus)-
the largest part of the choroid plexus
lobar holoprosencephaly-
the least severe form of the holoprosencephaly
ependyma -
the lining of the ventricles within the brain
brain stem-
the lower part of the brain composed of the pons, midbrain, and medulla oblongata
interthalamic adhesion- Aka
the mass of tissue, located in the third ventricle within the midline of the brain, which connects the two lobes of the thalamus; also referred to as the massa intermedia
arachnoid membrane-
the middle layer of the meninges
thanatophoric dysplasia-
the most common lethal skeletal dysplasia characterized by a cloverleaf skull with frontal bossing and hydrocephalus
alobar holoprosencephaly-
the most severe form holoprosencephaly
communicating hydrocephalus-
the obstruction of cerebrospinal fluid from a source outside the ventricular system
foramen magnum-
the opening in the base of the skull through which the spinal cord exits
cerebellar vermis-
the portion of the cerebellum, located within the midline of the brain, that connects its two hemispheres
craniosynostosis-
the premature closure of the cranial sutures with subsequent fusion of the cranial bones
prosencephalon- Aka
the primary brain vesicle also referred to as the forebrain; it eventually becomes the lateral ventricles, cerebral hemispheres, third ventricle, thalamus, hypothalamus, pineal gland, and pituitary gland
rhombencephalon- Aka
the primary brain vesicle also referred to as the hindbrain; it eventually becomes the cerebellum, medulla oblongata, and fourth ventricle pons,
mesencephalon-
the primary brain vesicle also referred to as the midbrain; it eventually becomes the cerebral peduncles, quadrigeminal plate, and cerebral aqueduct
cerebrospinal fluid-
the protective and nourishing fluid of the brain and spinal cord produced by the cells of the choroid plexus
cephalic index-
the ratio used for assessing fetal head shape
The most common intracranial tumor found in utero is
the teratoma.
What is The germinal matrix
thin-walled, pressure-sensitive vessels located in the the ventricles.
The cerebral aqueduct (aqueduct of Sylvius), located between the
third and fourth ventricles of the brain,
Each lateral ventricle communicates with the
third ventricle
aqueduct of Sylvius or the cerebral aqueduct connect the _____ _____ to the _____ _____
third ventricle fourth ventricle
The two lobes of the thalamus are located on both sides of the
third ventricle.
(TORCH) stands for
toxoplasmosis, other agents, rubella, cytomegalovirus, and Herpes simplex virus
The lateral ventricle is measured in the _____ plane at the level of the____?
transaxial atrium
The cerebellum is measured in the ____ plane at the same level as the ?
transverse cisterna magna and thalamus
Maternal serum screening, also referred to as the
triple screen,
Choroid Plexus Cysts has an association with
trisomy 18.
The third ventricle is located between the
two lobes of the thalamus.
hydrocephalus is also known as
ventriculomegaly
Enlargement of the lateral ventricle beyond 10 mm is referred to as
ventriculomegaly.
The abnormal enlargement of the ventricles within the brain is referred to as
ventriculomegaly.
Alpha-Fetoprotein (AFP) is initially produced by what 3 structures
yolk sac, fetal gastrointestinal tract, and the fetal liver.