brainPt1 Flashcards
ectoderm differentiates into? (9)
nervous system:
- brain
- spine
- peripheral nerves
epidermis, nails, hair, lining of mouth, nose, and anus
embryology of brain?
- ectoderm forms a neural plate
- crease appears on a plate that becomes a groove
- groove deepens and neural folds join to form a neural tube
Each end of neural tube has neuropores
what happened with them?
- They will be closed soon after
- If anterior neuropore doesn’t close – anencepahly
- If posterior end doesn’t close – spina bifida, pilondial cyst
After closure of both ends of the neural tube , anterior end develops into three vesicles?
- forebrain
- midbrain
- hindbrain
what does the forebrain contain?
- cerebrum (includes cerebral cortex, white matter, basal nuclei)
- diencephalon (thalamus, hypothalamus, epithalamus)
what does the midbrain contain?
midbrain (part of the brainstem)
what does the hindbrain contain?
- pons (part of brain stem), cerebellum
- medulla oblongata (part of brainstrem)
cranial sonography is the primary modality for screening and follow-up of? (3)
- intracranial hemorrhage (ICH)
- hydrocephalus
- congential anomalies of the neonatal brain
where is cranial sonography performed?
in neonatal intensive care units
sonographic exam and technique of cranial sonography?
- small footprint high frequency transducer 7-10MHz
- 5-7MHz for older infants with closing frontanelles or infants with a large amount of hair
sonographic exam and technique of cranial sonography?
- small footprint high frequency transducer 7-10MHz
- 5-7MHz for older infants with closing frontanelles or infants with a large amount of hair
Preterm infants are at risk for?
infection due to their immature immune system
3 windows that may be used to view the neonatal brain?
- anterior frontanelle (standard)
- posterior frontanelle (supplemental)
- mastoid frontanelle/ posterolateral (supplemental)
closure of the anterior frontanelle begins at what month? when does it close?
- begins at 9 month until it closes at 15 months
it is rare to scan the pediatric brain after what month?
9 months
Timing is essential for detection of hemorrhagic or ischemic brain damage when should you scan for a hemorrhage?
- A scan soon after birth will give information regarding prenatal onset of the lesions
- Hemorrhagic lesions mostly become visible within hours after the incident –develop around birth or few days after
- Ischemic lesions need time to develop-can be seen weeks after
what is a frontanelle?
- a soft spot between crainial bones
Anterior fontanelle is formed where?
at the junction of the coronal. sagittal, and frontal sutures
the posterior frontanelle is formed?
by the junction of the lambdoid and sagittal sutures
mastoid frontanelle is located?
- at the junction of the lambdoid and occipital sutures
define Cerebrum?
- what is it joined by
Largest section of the brain, divided into two hemispheres joined by the corpus callosum
define corpus callosum?
Largest white matter structure in the brain; contains nerve tracts that allow communication between the right and left hemispheres
define cerebral cortex?
the outermost layer of the cerebrum
what is the flax cortex?
fold of dura matter that divides the 2 hemispheres of the brain
define cerebellum?
Posterior portion of the brain, composed of two hemispheres
define choroid plexus?
Echogenic cluster of cells located within the lateral ventricles responsible for the production of CSF
define thalmus?
paired ovoid structures in the central brain
function of meninges?
- 3 protective membranes called the meniges cover/ protect the brain and spinal cord
3 layers on meninges?
- dura mater
- arachnoid
- pia mater
dura mater?
outer layer and most resilient
arachnoid layer of meninges?
- between the dura and pia
- contains subarachnoid space with CSF
Pia mater layer of meninges?
- surrounds the surface of the cerebral cortex
central nervous system includes?
- brain
- spinal cord
function of cerebrospinal fluid?
- CSF surrounds the brain and the spinal cord
- Acts like a buffer to help cushion the brain and spinal cord from injury
- Balanced between production and absorption of the fluid
3 divisions of the brain?
- cerebrum
- cerebellum
- brainstem
largest division of the brain?
cerebrum
what is the cerebrum divided into?
- right and left cerebral hemispheres
- cortex (grey matter), white matter
what are the right and left cerebral hemispheres separated by?
- fissure/ groove called the longitudinal fissure
whats the flax cerebri?
section of dura that lies within the fissure (helps separate the hemispheres)
the cortex is divided into what 4 lobes?
- frontal
- parietal
- occipital
- hemispheres
what is the lateral fissure- sylvian?
divides both thefrontal lobe and parietal lobe above from the temporal lobe on both sides
cerebellum is responsible for what body functions?
- movement and coordination
where is the cerebellum located?
at the back of the brain beneath the occipital lobes
the cerebellum is seperated from the cerebrum by the?
tentorium (a fold of dura)
the cerbellum is composed of 2 hemispheres with a midline structure called?
vermis that connects 2 hemispheres
what is the posterior fossa of the cerebellum?
- cavity in the scull containing the cerebellum, 4th ventricle, and brain stem
what is the brainstem?
a stalk-like structure connecting the cerebral hemispheres with the spinal cord
consisting of:
- mid brain
- pons
- medulla oblongata
function of the ventricular system?
pathway for the circulation of CSF
what are the paired lateral ventricles?
- largest
- located on either side within the cerebrum
each lateral ventricle is divided into 4 parts, what are they?
- frontal/ anterior horn
- occipital/ posterior horn
- body
- temporal horn
choroid plexus function?
- production and regulation of CSF
- located in all 4 ventricles
what is the largest portion of choroid plexus?
- glomus and located within the lateral ventricles (trigone)
what is the corpus callosum?
- connects the 2 sides of cerebrum
- largest white matter structure in the brain
- contains nerve tracts that allow communication between the right and left hemispheres of the brain
what is the largest white matter structure in the brain?
corpus callosum
what 4 things is the corpus callosum divided into?
- rostrum
- genu
- body
- splenium
what does the corpus callosum form?
the roof for the lateral and 3rd ventricle
what is the thalami?
- paired structures of gray matter
- located in the centre of the brain, one beneath each cerebral hemisphere, next to the 3rd ventricle
what is the cisterna megna?
- fluid-filled structures that communicated with the 4th ventricle
- lies between the cerebellum and the dorsal surface of the medulla
Scanning the neonatal head should be performed in a?
standardized manner with a specific sequence of images to highlight key anatomical structures
how to scan the anterior frontanelle?
- Scanning in the coronal plane will produce 6 to 8 images
- Maintain side-to-side symmetry while scanning
- Coronal images are obtained by systematically angling the transducer from the frontal lobe of the infant brain to the occipital cortex
Frontal Lobes – scan plane 1?
- Through frontal lobes at level of orbits and longitudinal fissure
- Scan is anterior to frontal horns
Frontal Horns – scan plane 2,3?
- Frontal horns (f) appear as triangular-shaped, fluid-filled spaces separated by the cavum septum pellucidum (cp)
- The head of the caudate nuclei (N) lie adjacent to the lateral walls of the ventricles
- The hypoechoic corpus callosum (cc) forms the roof of the cavum
The echogenic Y-shaped sylvian fissures (arrows) are seen laterally
Third Ventricle – scan plane 4 is at the level of the?
foramina of monro
- this is where the lateral ventricles and the 3rd ventricle communicate
The normal slit-like third ventricle is often difficult to visualize due to the fact that?
its transverse diameter often falls within the beam width
what will allow for visualization of the 3rd ventricle?
slight off axis angulation will offset the beam thickness effect and will allow visualization of the 3rd ventricle
Coronal Scan Posterior to the Third Ventricle – scan plane 5 what is seen?
- The echogenic choroid plexus is seen in the floor of the lateral ventricles and the roof of the third ventricle
- The Y-shaped sylvian fissures (SF) are seen laterally
- echogenic tentorium
- cerebellar hemispheres
- cisterna magna
Coronal Scan Posterior to the Third Ventricle – scan plane 5 what is seen?
- The echogenic choroid plexus is seen in the floor of the lateral ventricles and the roof of the third ventricle
- The Y-shaped sylvian fissures (SF) are seen laterally
- echogenic tentorium
- cerebellar hemispheres
- cisterna magna