Neonatal Head 3

How many sections (lobes) is the cerebral cortex divided into?

Four

The four lobes of the cerebral cortex are the ______, ______, ______, and ______ lobes.

frontal, parietal, occipital, temporal

What are gyri?

convolutions on the surface of the brain caused by infolding of the cortex

A ______ is a groove or depression on the surface of the brain separating gyri.

sulcus

What is the role of sulci in the brain?

they separate gyri and further divide the hemispheres into lobes

The hemispheres are divided into lobes by ______.

sulci

What appearance do extremely premature brains have on ultrasound?

a smooth appearance

Sulci are not detected sonographically until around ______ weeks.

26

What is the interhemispheric fissure?

the area where the falx cerebri sits and separates the two cerebral hemispheres.

The ______ cerebri sits within the interhemispheric fissure.

falx

Where is the Sylvian fissure located?

along the lateral-most aspect of the brain

What important vessel courses through the Sylvian fissure?

the middle cerebral artery

What conditions is fetal MCA Doppler assessment used to evaluate?

fetal cardiovascular distress, fetal anemia, and fetal hypoxia

MCA Doppler is a useful adjunct to ______ artery Doppler assessment.

umbilical

In what growth-related condition is MCA Doppler used as part of further evaluation?

intra-uterine growth restriction (IUGR)

What twin complications is MCA Doppler used in the additional work-up of?

twin to twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS)

What is the normal flow pattern in the fetal MCA?

high resistance flow with minimal antegrade flow in fetal diastole

What happens to MCA flow in pathological states?

it becomes low resistance flow

The change to low resistance MCA flow is mainly due to the fetal ______ theory.

head sparing

What condition is underpinned by the fetal head sparing theory?

asymmetrical intra-uterine growth restriction (IUGR)

In asymmetrical IUGR, what mismatch is typically seen in fetal measurements?

normal head circumference with decreased abdominal circumference

What happens to fetal cardiac output in chronic hypoxemia?

it is redistributed to maximize oxygen supply to the brain

In chronic fetal hypoxemia, cerebral arteries undergo ______ to increase blood flow to the brain.

vasodilation

What is the effect of cerebral vasodilation on blood flow?

it increases blood flow to the brain

What cardiac effect results from this redistribution and vasodilation?

a decrease in left ventricular afterload

What structures make up this collection of gray matter?

caudate nucleus, lentiform nucleus, claustrum, and thalamus

The head of the caudate nucleus at the ______ groove is the most common site for hemorrhage.

caudothalamic

What is the primary function of the caudate nucleus?

motor control

What other functions is the caudate nucleus associated with?

reward and cognition

What is the basal ganglia considered to be in terms of motor function?

a gate-keeping mechanism for the initiation of motor movement

What is the shape of the thalamus?

ovoid (egg-shaped)

The thalamus consists of two ______ brain structures.

ovoid

Where are the thalami located in relation to the third ventricle?

on either side of the third ventricle

Where is the thalamus located in relation to the brainstem?

superior to the brainstem

What is the function of the brainstem?

it connects the forebrain and the spinal cord

The brainstem is made up of the ______, ________, and ______________.

midbrain, pons, and medulla oblongata

What does the midbrain connect?

it connects the forebrain to the hindbrain

What are the two halves of the midbrain called?

cerebral peduncles

The midbrain includes the _______________, ____________, and ______.

cerebral aqueduct, tectum, and tegmentum

What passes through the pons and medulla oblongata?

fiber tracts between the brain and the spinal cord

What vital body functions are regulated by centers in the pons and medulla oblongata?

heart rate, respiration, and blood pressure

What part of the hindbrain has a cauliflower-like appearance and consists of two hemispheres?

the cerebellum

The cerebellum lies in the posterior cranial fossa under the ______ cerebelli.

tentorium

What connects the two hemispheres of the cerebellum?

the vermis

Where is the cerebellum located?

in the posterior cranial fossa

What structures make up the cerebrovascular system?

internal cerebral arteries, vertebral arteries, and the circle of Willis

The middle cerebral artery is a branch of the ______ carotid artery.

internal

Which artery and structure are commonly evaluated with Doppler ultrasound for cerebral blood flow?

the middle cerebral artery and the circle of Willis

What is the MCA a branch of?

the internal carotid artery

Most common disorder of the neonatal brain:

hydrocephalus

What defines Grade I intraventricular hemorrhage?

SEH or IVH without ventricular enlargement

What defines Grade II intraventricular hemorrhage?

SEH or IVH with minimal ventricular enlargement

What defines Grade III intraventricular hemorrhage?

SEH or IVH with moderate or large ventricular enlargement

What defines Grade IV intraventricular hemorrhage?

SEH or IVH with intraparenchymal hemorrhage

Neonatal pathology:

hydrocephalus, hypoxic-ischemic events, infection

What may result from applying too much pressure during an examination?

bradycardia