week 11- fetal CNS, face, neck, spine Flashcards
what germ layer does the CNS develop from
ECTOderm
when does CNS development start
week 5
neural tube fusion starts in ___ of embryo and extends to close ___ end at ~5.5 weeks followed by ___ end at 6 weeks
- midtrunk
- cranial
- caudal
neural tube is derived from the ___ and is open at the rostral and caudal ends
neural plate
prosencephalon
forebrain
forebrain develops the ___ and ____
- telecephalon
- diencephalon (thalamus)
midbrain develops the
mesencephalon
rhombencephalon
hindbrain
hindbrain develops the ___ & ___
- metencephalon (cerebellum & pons
- medulla
CSF is produced by
choroid plexus
locations of choroid plexus where CSF is produced (3)
- medial walls of lateral vent
- roof of 3rd vent
- roof of 4th vent
acts as a cushion or buffer for the brain’s cortex, providing a basic mechanical and immunological protection to the brain inside the skull, and it serves a vital function in cerebral autoregulation of cerebral blood flow.
CSF
the CSF occupies the ___ space and the __ system around and inside the brain and spinal cord
- subarachnoid
- ventricular
flow of CNS from lateral ventricle to the subarachnoid space
- LATERAL vent
- interventricular foramen of monroe
- THIRD vent
- aqueduct of sylvis
- FOURTH vent
- foramen of magenie/ luschka
- SUBARACHNOID space
foramen of __ is the median aperature
magendie
foramen of __ is the lateral aperture
luschka
the thalamus can be found on either side of the ___ ventricle
3rd
hypothalamus is ___ from thalamus
anteroinferior
the peneal gland is found ___ to the 3rd ventricle
posterior
pons and medulla are the __ part of the brain stem
inferior
what do the following do:
- lateral aperture (foramen of luschka)
- median aperture of magendie)
link the 4th ventricle to the subarachnoid space (great cistern)
bridges the communication between the 2 hemispheres
corpus callosum
at what time do cranial bones begin to ossify, choroid plexus fill the lateral ventricles almost entirely
end of first trimester
week 13
corpus callosum begins development at __ weeks and is completed by __ weeks
12
18
in weeks 13-15 the anterior horns of the lateral ventricles are __ of choroid plexus
devoid
ventricular view is at a level___ than the thalamic view
higher
what measurement is taken at the ventricular view
atrial measurement
the BPD, OFD, and HC measurements are taken at the ___ view
thalamic
pia/arachonoid matter can be seen covering sulci at __ to __ weeks
25-26 ( end of second trimester)
in the cerebrum & run parallel to the falx cerebri at the superior level (above the ventricles)
periventricular lines
sonographic appearance of periventricular lines
bilateral echogenic area
normal measurement of lateral ventricle at 13-40 weeks
<10mm
BPD measurement is from __ to __
- outer (side closest to probe includes skull)
- inner
what measurements are taken at the CSP & thalamic view
BPD & HC
- head shape
- cranial mineralization
- ventricles
- CSP
- Falx cerebri
- cerebellum & vermis
- Cistern magna
- Nuchal fold thickness
cranial structures routinely noted on US
____ a normal fold of skin seen at the back of the fetal neck
nuchal fold
Nuchal fold (NF)thickness is ameasurement of the distance from the outer edge of the ___ bone to the outer edge of the ___ in the midline.
occipital
skin
Nuchal ___ is measured later in pregnancy whereas Nuchal ___ is measured earlier in pregnancy
fold
translucency
Nuchal fold measurement should NOT exceed
6mm
orbits and eyes can be seen at __ weeks but clearly seen by __ weeks
12
16
we are looking for the ___ &__ of orbits
number
distance
seen as a small echogenic focus within the orbit
lens
hypotelorism
eyes too close together
hypertelorism
eyes too far apart
microphthalmis
eyes are rlly small
orbital view is obtained in ___ or ___ plane
coronal
trv
2 types of orbital measurement
- outer orbital distance
- inner orbital distance
measurement of choice for orbits
outer orbit
on the fetal face we look for
- cleft lip
- fetal swallowing & tongue movement
nose & lips best seen in the ___ plane
coronal
profile is taken in the ___ view
midline sagittal
profile demonstrated the presence and normal configuration of``
- nasal bone
- lips
- chin
- forehead
short ears seen in trisomy ___
13 & 18
low set ears are seen in trisomy __
21
facial screening is limited by
- too little or too much amniotic fluid
- bone shadowing
- maternal obesity
- fetal position
fetal neck images are in ___ planes
- coronal
- axial
- sag
evaluate the fetal neck for (3)
- cervical spine
- airway
- masses
Nuchal fold measurement between 15-22wks should be
<6mm
if nuchal fold is >6mm this is associated with increased risk for
trisomy 21
landmarks for transcerebellar
- cavum septum pellucidum (CSP)
- cerebellum
- cisterna magna
spine should have __ ossification centres
3
1) also termed vertebral body& anterior ossification center
centrum
2 &3) posterior elements, located posterior to the fetal spinal canal within the laminae
rt & lt neural processes
both posterior elements of spine are visualized by __ weeks
12
spinal canal runs through the ___ and __ ossification centres and during the scan can be seen until the level of the ___
-rt & lt neural processes
2&3
spine normally widens slightly in the __ and ___ areas`
cervical
lumbar
spine normally narrows at the ___
sacrum
in the sagittal plane, ___ ossification centres can be imaged
2
in the coronal plane, __ ossification centres can be imaged
2
in the transverse plane, __ ossification centres can be identified
3
how many vertebrae are there in each section? total?
cervical- 7 thoracic- 12 lumbar-5 sacral-5 coccygeal-4 TOTAL = 33
