Chapter 24 - the Fetal head and brain Flashcards
(138 cards)
1
Q
By 4.5 weeks the neural plate will give rise to the
A
Central nervous system
2
Q
What will give rise to the central nervous system
A
Neural plate
3
Q
The neural plate will give rise to the
A
Neural tube
4
Q
The neural tube will become the
A
Spine and Brain
5
Q
The brain is divided into three primary vesicles
A
Prosencephalon (forebrain)
-Mesencephalon (midbrain
Rhomobencephalon (hind brain
6
Q
The skull consists of how many cranial bones
A
8
7
Q
The bones of the skull are. connected by structures known as
A
Sutures
8
Q
Premature fusion of the sutures of the brain
A
Craniosynostosis
9
Q
Spaces that exist between the fetal bones are known as
A
Fontanelles or soft spots
10
Q
Anterior fontanelle is known as
A
Bregma
11
Q
Posterior fontanel is known as
A
Lambda
12
Q
Opening in the base of the cranium through which the spinal cord travels
A
Foramen Magnum
13
Q
The brain can be divided in two man parts
A
Cerebrum
Cerebellum
14
Q
Largest part of the brain
A
Cerebrum
15
Q
The normal cerebrum contains multiple
A
Sulci
Gyri
16
Q
How many cerebral lobes are there
A
Six
17
Q
What are the 6 cerebral lobes
A
Frontal Lobe
(2) temporal
(2) parietal
Occipital
18
Q
Cerebrum can be divided into ___
A
Rt hemisphere
Lt hemisphere
19
Q
Intehemisphere fissure divides
A
Cerebrum into Rt and Lt hemisphere
20
Q
a double fold of dura mater
A
Falx cerebri
21
Q
Where is the falx cerebra located in
A
The inethermispheric fissure
22
Q
Provides communication between Right and left haves of the brain and link the cerebral hemispheres in the midline
A
Corpus Callous
23
Q
Three protective tissue layers that cover the brain and spinal cord
A
Meninges
24
Q
Inner most layer of meninges
A
Pia Matera
25
Middle layer of meninges
Arachnoid membrane
26
Outermost layer of the meninges
Dura mater
27
The corpus callous should be fully intact by when
18 to 20 weeks
28
Corpus callous consists of 4 parts
Rostrum
Genu
Body
Splenium
29
Absence of the all or part of the corpus callous is referred to as what
Agenesis of the Corpus Callous
30
Cavum septum Pellucidum is
Midline brain structure
31
Where is the CSP located
Anterior portion between the frontal horns of the lateral ventricles
32
What appears as an anechoic box shaped structure in the axial plane
CSP
33
CSP should also be seen between what weeks
18 and 37 weeks
34
The CSP does not communicate with what
Ventricular system
35
The two lobes of the thalamus are located on both sides of the
Third ventricle
36
What passes through the third ventricle to connect to the two lobes of the thalamus
Massa intermedia
Interthalamic Adhesion
37
The ventricular system is composed of how many ventricles
Four
38
What is the primary function of the ventricular system
Provides cushioning for the brain
39
Each ventricle is lined by a membrane known as
Ependyma
40
Where are the paired lateral ventricles located on
Both sides of the falx cerebra within the cerebral hemispheres
41
Lateral ventricles are also known as
Right & Left
1st and 2nd
42
Each lateral ventricle consists of what
Frontal
Temporal
Occipital horn
43
The body of the lateral ventricle is located between
Frontal and Occipital horn
44
Where do the body, temporal horn, and occipital horn meet at?
Trigone of the left atrium
45
Within the atria of both lateral ventricles lies
Choroid plexus
46
Cells responsible for production of CSF
choroid plexus
47
Where are the chorioid plexus found
in the roof of the 3rd and 4th ventricles
48
What allows communication between the third ventricle and lateral ventricles?
The foramen of Monro
49
The third ventricle is located between
The two lobes of the thalamus
50
The third ventricle connects to the fourth ventricle by what?
Aqueduct of Sylvius
(cerebral aqeuduc)
51
The fourth ventricle is located how to the cerebellum
Anteriorly
52
4th ventricle has how many apertures
three
53
The fourth ventricle has three apertures that are referred to as what?
Foramina of Luscka
54
Two apertures of the fourth ventricle allow?
CSF to travel from the fourth ventricle to the subarachnoid space
55
Aperture allows CSF to cistern magna
Foramen of MAgendie
56
Flow of CSF
Lateral Ventricles
Foramina of Monro
Third Ventricle
Cerebral Aqueduct
Fourth Ventricle
Median or lateral aperatures
57
Reabsorption of CSF into the venous system
Arachnoid Granulations or
also called arachnoid villi
58
Cistern magna is located
In the posterior fossa of the carnium
59
Largest cistern of the head
Cistern Magna
60
Cistern magna is located where
-posterior to the cerebellum -between the cerebellar vermis,
-inferior surface of the occipital bone
61
Cerebellum consists of what
Two hemispheres
RT & LT
62
Structure noted on the under surface of the cerebellum and become distorted with spina bifida
Cerebellar tonsils
63
BPD is obtained at the level of the?
Falx cerebri
Thalamus
CSP
3rd ventricle
64
How is BPD obtained
Outer table of the proximal parietal bone
Inner table of the distal parietal bone
65
BPD is from
leading edge to leading edge
66
Head shape that is too wide or round
Brachycephalic
67
Head shape is too elongated or narrow
Dolichocephaly (scaphocephaly)
68
Normal to Medium sized skull is termed
Mesocephalic
69
Cephalic Index is what?
BPD/OFD x 100
70
A cephalic index of less than 75 deonates what?
Dolichocephalic
71
A cephalic index of more than 85 denotes what
Brachiocephalic
72
Where is the lateral ventricle measured at
Transaxial plane of the level of the left atrium
73
Why is the atrium the optimal site for measuring the lateral ventricle?
Because this is where the first region where ventricular enlargement occurs
74
Lateral Ventricles does not typically measure more than ?
10mm
75
Enlargment beyond 10mm is referred to as?
Ventriculomegaly
76
The cerebellum grows at a rate of ?
1mm per week between 14 and 21 weeks
77
The depth of the cisterna magna should not measure?
More than 10 mm
Less than 2 mm
78
CM measures bigger than 10 mm is known as
Mega cistern Magna
Dandy Walke complex
79
CM measures less than 2 mm is
Arnold Chiari II malformation
80
The abnormal enlargement of the ventricles within the brain
Ventriculomegaly
81
Dilatation of the ventricular system caused by an increased volume of CSF
Hydrocephalus
82
Severe case of Ventriculomegaly
Hydrocephalus
83
What does Aqueductal Stenosis Cause?
Hydrocephalus ;Obstruction to the flow of CSF, resulting in a backup of the fluid in cerebral ventricles
84
The most common cranial abnormality ?
Ventriculomegaly
85
Suspicion of ventricular dilatation occurs when?
atrial diameter measures more than 10mm
86
Ventriculomegaly can have what sonographic finding?
Dangling chorioid plexus cyst
87
Echogenic choriod plexus, hanging limp and surrounded by CSF within dilated lateral ventricle
Dangling choroid plexus cyst
88
Hydrocephalus can be describes as what
Mild
Moderate
Severe
89
There are two types of hydrocephalus
Communicating
Non communicating
90
Obstruction lies outside the ventricular system
Communicating hydrocephalus
91
Obstruction lies within the ventricular system
Noncommunicating
92
The most common cause of Hydrocephalus?
Aqueduct stenosis
93
Sonographic Findings of Ventriculomegaly
Atrium of the lateral ventricle measures greater than 10 mm
Atrial measurement measuring 15 mmis considered ventriculomegaly
Dangling choriod plexus
Dilatation of any part of the ventricular system
94
When the cerebral aqueduct between the third and fourth ventricles of the brain are narrowed
Aqueduct stenosis
95
Entire cerebrum is replaced by a large sac containing CSF
Hydrancephaly
96
with hydrancephaly ____
Falx Cerebri is partially or completely absent
Brain stem and basal ganglia are maintained and surrounded by CSF
Cerebral cortex will not be identified
97
What causes hydrancephaly
Bilateral occlusion of the internal carotid arteries
Intrauterine Infections (Cystomegalovirus / Toxoplasomosis)
98
Severe Ventriculomegaly and Hydranencephaly what will be present?
Rim of cerebral tissue maintained
99
Hydranencephaly there what will not be visualized?
Cerebral mantal
100
Midline brain anomaly that is associated with not only brain abberations but also atypical facial features
Holoproencephaly
101
There are three main types of holoproencephaly
Alobar
Semilobar
Lobar
102
Cortex will look like a pancake, cup, or ball
ALobar holoproencephaly
103
Alobar is Holoproencephaly diagnosed when what is absent?
Absence of Corpus Callosum, CSP, Third Ventricle, Interhemisphereic Fissure, and FAlx Cerebri
104
What are the Sonographic Features of Alobar Holoproencephaly
Horseshoe shaped monoventricle
Fused echogenic thalami
Absence of CSP, Corpus Callosum, Third Ventricle, Falx Cerebri, Interhemisphereic Fissure
105
Facial Anomalies of Alobar Holoproencephaly
Cyclopia
Hypotelorism
Proboscis
Median cleft lip
Anopthalmia
Cebocephaly
106
Spectrum of posterior fossa abnormalities that involve the cystic dilatation of the Cisterna Magna and Fourth Ventricle
Dandy Walker Malformation
107
Dandy walker Malformation
Developmental abnormaility in the roof of the fourth ventricle
108
Sono findings of DWM
Enlargement of Cisterna Magna > 10 mm in the anteroposterior dimension
Communication of the enlarged Cisterna Magna with a dilated fourth ventricle
Agenesis or hypoplsia of the Cerebellar Vermis
Varying degrees of Ventriculomegaly
109
Enlargement of the Cisterna Magna without the involvement of the fourth ventricle
Mega cistern Magna
110
Sono findings of Mega cistern magna
Enlargement of the Cisterna Magna > 10 mm in the anteroposterior dimension
Normal cerebellum and fourth ventricle
111
Bridge of tissue located within the midline of the brain that connects the two cerebral hemispheres.
Corpus callousum
112
What is located inferior to the Corpus Callosum
CSP
113
Mostly often if the Corpus Callosum is absent then what else is also absent?
CSP
114
Agenesis of the Corpus Callosum and CSP is linked to what anomalies?
Trisomy 8
Trisomy 13
Trisomy 18
holoprosencephaly
Aqueductal Stenosis
Apert Syndrome
DWM
115
Sonographic Findings of Agenesis of the Corpus Callosum and CSP
Partial or complete absence of the Corpus Callosum and CSP
Sunburst Sign - Radial arrangement of the sulci which produces a "spoke wheel" pattern
Colpocephaly - Small frontal horns and enlarged occiptal horns
Elevated and dilated third ventricle
116
Development of fluid filled clefts within the cerebrum
Schizencephaly
117
Cyst communicates with the ventricular system
Porencephaly
118
Porencephaly
Fetus has experience a hemorrhage within one or both hemispheres of the brain
119
Smooth brain where there is no gyri or sulci within the brain
Lizzencephaly
120
Protrusions of intracranial contents through a defect in the skull
Cephalocele
121
The most common location for a Cephalocele?
Occipital region
122
Protrusions that include brain tissue
Encephalocele
123
Toxoplasmosis
Other Infections
Rubella
Cystomegalovirus
Herpes
Torch stands for
124
The most common intracranial tumor found in utero is what?
Teratoma
125
Choroid Plexus Papillomas
Found in the CP increased production of CSF which leads to ventriculomegaly
126
Intracranial Hemorrhage is a common worry for infants?
Weighing less than 1,500 and those born before 32 weeks
127
The most common risk for intrauterine intracranial hemorrhage is listed as?
Maternal placental disorder (Cociane and Amniocentesis are others)
128
Origin of the Intracranial Hemorrhage is?
Germinal matrix
129
Group of thin walled pressure sensitive vessels located in the subependymal layer of the ventricle
germinal matrix
130
Normal cerebral circulation typically has what kind of Doppler pattern?
High impedance
131
Doppler assessment of the Middle Cerebral Artery is effective for evaluating?
Potential Hypoxia
132
Brain Sparring Syndrome
Fetus is starved for oxygen
Redistribution of the blood to the vital organs (BRAIN)
Occurs in order to spare it from damage
133
The pulsatility index of the MCA varies?
With gestational age, normally decreases with advancing gestational age
134
The resistance pattern of the MCA should be?
Greater than the umbilical artery
135
The MCA/Umbilical Artery Resistive Index is?
normally above 1.0
136
MCA / Umbilical Artery Resistive Index less than 1.0 is considered?
Abnormal
137
Ateriovenous malformation that occurs within the fetal brain
Vein of Galen anyerusm
138
Anechoic mass within the midline of the brain that contains turbulent arterial and venous flow
Fetal Hydrops
Cardiomegaly
Sonofindings of vein of glean anyersum
