Module 1 Flashcards
Define the Horizontal Plane.
AKA the axial or transverse plane, looking at the brain from above or below.
Define the Coronal Plane.
AKA the frontal plane, looking at the brain from the front or the back.
Define the Sagittal Plane.
Looking at the brain from the left or the right.
Mid-sagittal plane: when the slice is along the midline.
Para-sagittal plane: when the slice is off the midline.
Above the midbrain, what are the relationships between absolute and relative orientation terms?
Anterior = rostral
Posterior = caudal
superior = dorsal
inferior = ventral
In/below the midbrain, what are the relationships between absolute and relative orientation terms?
anterior = ventral
posterior = dorsal
superior = rostral
inferior = caudal
What is gray matter made of, and what are other names for it?
Unmyelinated cell bodies. When grouped together, they are called nuclei, cortex, or laminae.
What is white matter made of, and what are other names for it?
Axons that are concentrated together. AKA nerves, fibers, tracts, lemniscus, or commissures.
What are projection fibers?
Axons that relay impulses between the cortex, brainstem, and spinal cord.
What are commissural fibers?
Fibers that cross between hemispheres, and connect the same structure on R/L sides of the brain.
What are association fibers?
Fibers that connect cortical areas within a hemisphere.
What is the cortex, and define a gyrus, sulcus, and fissure?
Cortex: the folded layer of gray matter on the outer surface of the brain.
Gyrus: outward fold
Sulcus: inward fold
Fissure: a deep sulcus
Where are the following fissures located? (longitudinal fissure, sylvian fissure, central sulcus, parietal-occipital sulcus, precentral and postcentral gyri, and the cingulate sulcus and gyrus)
Longitudinal fissure: large fissure at the top + center of the brain that runs down the entire length, separating the hemispheres.
Sylvian fissure: on the lateral aspect of the brain, and separates the frontal lobe from the temporal lobe.
Central sulcus: superior and runs down the lateral aspect of the brain, separates the frontal and parietal lobes.
Parietal-occipital sulcus: separates the parietal and occipital lobes, can only be seen medially.
pre-central gyrus: the gyrus anterior to the central sulcus.
post-central gyrus: the gyrus posterior to the central sulcus.
cingulate gyrus and sulcus: surround the corpus collosum.
From top to bottom, what is the order of brainstem structures?
Midbrain, pons, medulla.
Where is the cerebellum located?
Posterior/dorsal to the brainstem.
Where is the thalamus located?
On top of the brainstem, but is not part of the brainstem.
What are interthalamic adhesions?
Bands of white matter that connect the R/L sides of the thalamus.
What does the anterior fossa hold, and how is it separated from the middle fossa?
It carries the frontal lobe, and is separated from the middle fossa by the lesser wing of the sphenoid bone.
What does the middle fossa hold, and how is it separated from the posterior fossa?
It carries the temporal lobe, and is separated from the posterior fossa by the petrous ridge of the temporal bone.
What does the posterior fossa carry?
The cerebellum and brainstem.
What is the foramen magnum?
The large opening at the base of the skull that allows the spinal cord and brainstem to enter the skull.
What is the cervicomedullary junction?
Where the spinal cord ends and the medulla begins. It sits right at the level of the foramen magnum.
What is the dura mater, and what are its features (2 layers)?
It is the hard, fibrous, outermost meningeal layer.
Outer periosteal layer: adhered to the inner skull surface.
Inner meningeal layer: fused to the periosteal layer, except when it extends inwards to separate hemispheres + cortex from the cerebellum.
What is the falx cerebri?
A flat sheet of dura that separates the R/L cerebral hemispheres.
What is the tentorium cerebelli?
A tent-like sheet of dura that separates the cerebellum from the cerebrum. It is superiorly attached to the falx cerebri.
What is the tentorial notch?
The triangular opening when the tentorium cerebelli and the falx cerebri meet. It allows the midbrain to come up to the middle of the brain.
What is the arachnoid mater?
The spidery, middle meningeal layer which is attached to the inner dural surface. It contains CSF, which percolates around the brain.
What is the pia mater?
The innermost meningeal layer that adheres to the brain’s surface, and contains blood vessels.
What are sinuses?
Where the meningeal layer of the dura separates from the periosteal layer of the dura.
What is a herniation?
A severe displacement of CNS structures, where they push into abnormal areas.
What is a subfalcine herniation?
A herniation that happens below the falx cerebri.
What is an uncal transtentorial herniation?
When structures get pushed into the tentorial notch.
What are the 2 potential spaces?
The epidural space and the subdural space.
What is the 1 actual space, and how is it held open?
The subarachnoid space (contains CSF). It is held open by trabeculae, and by large arteries and veins.
What is a hematoma?
A collection of blood.
What are the 3 features of an epidural hematoma?
- Fast spreading
- Lens shaped on a CT scan
- can cross the midline
What are the 3 features of a subdural hematoma?
- It is crescent shaped
- the venous bleed is slow
- It cannot cross the midline because of the falx cerebri
What are the characteristics of an acute subdural hematoma?
The injury is due to a high acceleration, and it shows up brighter on a CT scan because the blood is vey dense.
What are the characteristics of a chronic subdural hematoma?
The blood is less dense and liquefied so it shows up greyer on a CT scan, it develops over time and symptoms take a while to show up, and they commonly happen in older adults.
What are the 3 characteristics of a subarachnoid hematoma?
- Very fast bleeds
- 25% of people die right away
- Results in lots of intercranial pressure
How do the meningeal layers of the brain and spinal cord (SC) differ?
The dura is only made up of the meningeal layer in the SC. It also isn’t right up against the bone; there is a layer of epidural fat.
What are the vertebral foramen?
They make up the canal that lets the SC travel down through the vertebrae.
What are the interverterbal foramen?
The openings between the vertebrae where spinal nerves exit through.
What are denticulate ligaments?
Extensions of pia mater from the SC that fuse to the dura to hold the SC in place.
Where is CSF created?
It is created by the choroid plexus in the lateral brain ventricles.
What are the components of the lateral ventricles, and what connects them to the 3rd ventricle?
R/L lateral ventricles are connected centrally. They are made up of the anterior horn, body, atrium (wider region), posterior horn, and inferior horn.
It connects to the 3rd ventricle via the intraventricular foramen of Monro.
What are the components of the 3rd ventricle, and what connects it to the 4th ventricle?
It is thin, narrow, and runs along the midline between the 2 parts of the thalamus. It connects to the 4th ventricle via the cerebral aqueduct.
What are the components of the 4th ventricle, and what connects it to the subarachnoid space?
It is dorsal to the pons and medulla, and ventral to the cerebellum.
The foramen of Luschka are lateral openings to the subarachnoid space.
The foramen of Magendie is the medial opening to the subarachnoid space.
What are cisterns?
Widenings of the subarachnoid space.
What is the cisterna magna?
The largest cistern located near the foramen magnum.
What is the lumbar cistern?
Cistern located in the lumbar spine and contains the cauda equina. This is where CSF is usually drawn from for medical purposes.
How is the white matter of the SC divided?
White matter makes up the outer part of the SC.
Ventrally, there is the ventral median fissure. Dorsally, there is the dorsal median septum.
Ventrally, there are anterolateral sulci. Dorsally, there are posterolateral sulci.
The anterior SC column is between the 2 anterolateral sulci. The posterior column is between the 2 posterolateral sulci. The lateral columns are between the posterolateral and anterolateral sulci on R/L sides.
How is the gray matter of the SC divided?
Gray matter makes up the inside of the spinal cord. It is butterfly-shaped.
There is the dorsal/posterior horn, the intermediate zone, and the ventral/anterior horn.
What types of information do dorsal and ventral roots carry, and where to they arise/lead to?
Dorsal -> afferent info.
Ventral -> efferent info.
Ventral rootlets arise from the anterolateral sulcus and leads into the mixed spinal nerve.
Dorsal root ganglion come into the posterolateral sulcus from the dorsal root and mixed spinal nerve.
