Neonatal Head 2

What role do the subarachnoid space and cisterns play?

they play a role in the flow of cerebrospinal fluid (CSF)

What does the narrow subarachnoid space contain?

a small amount of cerebrospinal fluid (CSF) surrounding the brain and spinal cord

What is the cisterna magna?

one of the largest subarachnoid cisterns

What is the echogenicity of the cisterna magna on ultrasound?

anechoic

Where is the cisterna magna located?

in the posterior fossa between the medulla oblongata, cerebellar hemispheres, and occipital bone

How does ventricular size change with gestational age?

ventricular size varies with gestational age

How do ventricles in a premature infant compare to those in a term infant?

a premature infant will normally have larger-appearing ventricles than a term infant

How common is minor asymmetry of the lateral ventricles in infants?

it occurs in 20% to 40% of infants

What is a variant?

coarctation of the ventricle

How will a variant appear as?

as a cyst in coronal view at the superior and lateral ventricle

Flow of cerebrospinal fluid (CSP)

choroid plexus of the lateral ventricles → interventricular foramina (Monro) → third ventricle → aqueduct of Sylvius → fourth ventricle → foramen of Magandi → cistern Magna → spinal cord

What percentage of CSF is formed by the choroid plexuses of the lateral, third, and fourth ventricles?

approximately 40%

Where is the remainder of CSF produced?

from extracellular fluid movement from blood through the brain and into the ventricles

What is the mass of special cells located in the atrium of the lateral ventricles?

choroid plexus

What is the function of the choroid plexus cells?

they regulate intraventricular pressure by secreting or absorbing cerebrospinal fluid (CSF)

What is the glomus?

the tail of the choroid plexus

Why is the glomus clinically important?

it is a major site for bleeding

What is the cavum septum pellucidum (CSP)?

a thin triangular space filled with cerebrospinal fluid (CSF)

Where is the CSP located?

between the anterior horns of the lateral ventricles and inferior to the corpus callosum

When does the CSP usually close?

within the first 3 to 6 months of life

Can the CSP persist, and if so, how?

yes, it may persist for life in some individuals

What is the cavum vergae?

a posterior extension of the CSP

When does the cavum vergae normally close?

around 6 months of gestation

In what situations may the cavum vergae still be seen?

it may be seen in some preterm infants

What connects the two cerebral hemispheres?

the corpus callosum

From what bones and regions do the cerebral hemispheres extend?

from the frontal to occipital bones above the anterior and middle cranial fossae

What separates the two cerebral hemispheres?

the longitudinal fissure

What structure projects into the longitudinal fissure?

the falx cerebri

Where is the quadrigeminal fissure located?

posterior and inferior to the cavum vergae

Where is the vein of Galen located in relation to the quadrigeminal cistern region?

posterior

What should be done to distinguish a fissure from an enlarged vein of Galen?

doppler should be performed

What is the function of the corpus callosum?

it connects the left and right cerebral hemispheres and allows communication between them

The corpus callosum spans part of the ______ fissure.

longitudinal

The four main parts of the corpus callosum are ______, ______, ______, and ______.

rostrum, genu, body, splenium

What does the corpus callosum form in relation to the lateral ventricles?

it forms the roof of the lateral ventricles

Where is the corpus callosum located in relation to the cavum septum pellucidum (CSP)?

it is superior to the CSP

The genu develops earlier than the ______ and ______ of the corpus callosum.

body, splenium

What part of the corpus callosum is described as the dorsal element?

the genu

What can occur if a uterine insult affects development of the corpus callosum?

development may be partially arrested or complete agenesis may occur

What does ACC stand for?

absence of the Corpus Callosum

What are the two main components of the cerebrum?

gray matter and white matter

What is the cerebral cortex composed of?

gray matter

Where is white matter located in the cerebrum?

in the innermost portion of the cerebrum

The largest and densest bundle of white matter is the ______.

corpus callosum