Chapter 3 RADR 2340

Limbic system

"the emotional brain" (emotions, anger, aggression, fear, sorrow, sexual)

Review the axial MR image below. Which number labels the third ventricle?

#110

Review the axial MR T2-weighted image below. Number 16 labels the:

#16 Choroid plexuses

Refer to the image below. Which structure of the cerebellum is labeled as number 3?

#3- VERMIS

Refer to the image below. Which structure of the brainstem is labeled as number 4?

#4- Cerebral peduncle

Refer to the image below. Gray matter is labeled as what number?

#4- gray matter

Review the axial MR image below. Which number labels the fourth ventricle?

#5- Fourth Ventricle

Refer to the image below. Which structure of the brainstem is labeled as number 5?

#5- OLIVE

Review the midsagittal MR image below. The cerebellar tonsils are labeled as what number?

#5- Tonsils

Review the midsagittal MR image below. What number labels the cerebellar tonsils?

#5- Tonsils

Review the midsagittal MR image below. What structure of the brainstem is labeled as number 6?

#6- PONS

Review the coronal MR image below. What number labels the trochlear cranial nerve?

#6- Trochlear

Review the sagittal MR image below. The thalamus is labeled with the number?

#9- thalamus- MR Image

Three structures comprise the diencephalon:

(1) Epithalamus (2) Thalamus- largest component, forms the lateral walls (3) Hypothalamus

corpus callosum

(1) Rostrum - the inferior portion of the anterior curve ("R" in illustration) (2) Genu - the anterior curve ("G" in illustration) (3) Body - the upper arched portion ("B" in illustration) (4) Splenium - the posterior portion ("S" in illustration)

The parahippocampal gyrus encloses two structures of the limbic system:

(1) The amygdala (2) The hippocampus

Within the cerebral peduncles are two specialized areas:

*red nucleus (motor tract relays impluses from cerebrum to cerebellum) *substantia nigra (melanin, darker pigment). secretes dopamine, a neurotransmitter that is necessary for control of muscle reflexes

Which of the following structures are parts of the brainstem? Midbrain & Pons

1 and 2 only

Which of the following are parts of the limbic system of the brain? (1) Amygdala(2) Hypothalamus(3) Hippocampus

1 and 3 only

Which of the following brain structures are parts of the limbic system? (1) Fornix(2) Cingulate gyrus(3) Amygdala

1, 2, and 3

Which of the following are pure motor nerves in function? (1) Vagus(2) Trochlear(3) Hypoglossal

2 and 3 only

Hypothalamus (forms floor of 3rd ventricle)

A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

What is the tegmentum of the brainstem?

A specialized sheath that connects all three portions of the brainstem

Suprasellar cistern

Also known as the chiasmatic cistern Located above the sella turcica Contains the optic chiasm and the circle of Willis

Which subarachnoid cistern runs along the lateral sides of the midbrain?

Ambient Cistern

The portion of the limbic system that functions in processing and expressing emotions, such as aggression, anger, and fear, is the:

Amygdala

The arteries that supply the frontal, parietal, and temporal lobes of the cerebrum, as well as the orbits, are the:

Anterior cerebral arteries

Cingulate Gyrus

Arch-shaped, raised cerebral fold that closely follows the superior arch of the corpus callosum

What are the basal nuclei?

Areas of gray matter located deep within the cerebrum that function together to coordinate muscle action and movement

Areas of gray matter located deep within the cerebrum that function together to coordinate muscle action and movement are termed the

Basal Nuclei

The right and left vertebral arteries unite to form the:

Basilar Artery

Which cranial nerve provides sensory and motor functions through branches to the eye regions as well as the upper and lower jaws?

CN V- Trigeminal Nerve

Which cranial nerve innervates the lateral rectus muscles of the eyes?

CN VI ABDUCENS

What is located in the subarachnoid space?

CSF- serves as the 3rd layer of cushion for the brain

The basal nuclei are the:

Caudate nucleus Runs along the lateral ventricle Includes three portions: head, body, and tail Lentiform nucleus Shaped like a lens (biconvex) Located between the insula, caudate nucleus, and thalamus Includes two divisions: globus pallidus and putamen Claustrum Thin, linear structure Located between the insula and lentiform nucleus Amygdala Small, almond-shaped nucleus Located anterior to inferior horn of lateral ventricle Functions as part of limbic system

Rope-like bands of white matter that pass through the midbrain are the:

Cerebral peduncles

The structure(s) that produce cerebrospinal fluid are termed:

Choroid Plexuses

Epithalamus (forms roof of 3rd ventricle)

Contains pineal body. Involved in olfactory senses and sleep/wake cycle

Which portion of the cerebellum relays motor impulses via the thalamus to the cerebrum?

Dentate nucleus

The epithalamus, thalamus, and hypothalamus are portions of the:

Diencephalon

The portion of the diencephalon that forms the roof of the third ventricle is the:

Epithalamus

All of the following are pure sensory nerves in function, except:

FACIAL

Refer to the image below. Which dural fold is labeled as number 3?

Falx cerebelli

Which of the following functions as an efferent pathway connecting the hippocampus to the mammillary bodies and to other functional areas of the brain?

Fornix

Review the axial MR image below. Which ventricular structure is labeled as number 4?

Frontal Horn of lateral ventricle

The division of the brain that contains the language centers is the:

Frontal lobe

The cortex of the cerebrum is comprised of:

Gray Matter

Refer to the image below. Number 4 labels the:

Gray matter of cerebral cortex

The short, deep vein formed by the junction of the internal cerebral and basal veins is the:

Great cerebral vein

The cranial nerve known as the glossopharyngeal nerve is number:

IX glossopharyngeal nerve.

The portion of the midbrain that relays auditory stimuli to the thalamus is the:

Inferior colliculi

The portion of the diencephalon that connects the pituitary gland to the hypothalamus is the:

Infundibulum

White matter, forming corpus striatum "striped body"

Internal capsule - separates the thalamus and caudate nucleus from the lentiform nucleus External capsule - separates the claustrum from the lentiform nucleus Extreme capsule - separates the claustrum from the cortex of insula

The communicating channel between the lateral and third ventricles is

Interventricular foramen

What is the function of cerebrospinal fluid?

It serves as a cushion to protect the brain.

The middle cerebral artery supplies the:

Lateral cerebrum and basal ganglia

The primary divisions of the cerebellum are the:

Lateral hemispheres

Prepontine cistern

Lies below and anterior to the pons Connected to the cerebellopontine angle cistern laterally

Interpeduncular cistern

Located between the midbrain peduncles Communicates inferiorly with the prepontine cistern

Cerebellopontine angle (CPA)

Located lateral and anterior to the pons and cerebellum Contains cranial nerves V, VII, and VIII as well as the superior and anterior inferior cerebellar arteries

Quadrigeminal cistern

Located posterior to the midbrain colliculi (quadrigeminal plate) between the splenium of the corpus callosum and the superior cerebellum

Mammillary Bodies

Memory recognition and relay station, receiving impulses from the fornix and transmitting them to the thalamus and midbrain

Three structures comprise the brainstem:

Midbrain Pons Medulla oblongata

The portion of the cerebellum that connects it to the pons is the:

Middle peduncles

Sagittal MRI - Cerebellum

Note The fourth ventricle appears triangular in this plane and is immediately anterior to the cerebellum. The cerebellar tonsils project downward from the lateral hemispheres and toward the medulla oblongata.

The olfactory nerve is cranial nerve number:

ONE

The division of the brain that contains the visual perception centers is the:

Occipital Lobe

Refer to the image below. Which cranial nerve is labeled as number 1?

Oculomotor

Cranial nerve III controls several eye muscles and is also known as the:

Oculomotor nerve

Cisterna magna

One of the largest cisterns Located in the lower posterior fossa between the medulla oblongata, occipital bone, and the hemispheres of the cerebellum Continuous with the subarachnoid space of the spinal canal

Midsagittal MRI of brain

Outlining the lateral ventricle is the corpus callosum. The anterior curve is termed the genu and the posterior curve, the splenium. The third ventricle is not visible because the thalamus provides the lateral wall, and this patient has an adhesion in the thalamus

The division of the brain located posterior to the central sulcus is the:

Parietal lobe

Tentorium cerebelli

Partition between the cerebrum and the cerebellum

Falx cerebelli

Partition between the two cerebellar hemispheres

The portion of the diencephalon that acts as the biologic clock for the body is the:

Pineal Gland

All of the following are part of the diencephalon, except: Thalamus Epithalamus Pit. Gland Pons

Pons

In the cerebral arterial circle (of Willis), which artery connects the anterior circulation with the vertebral-basilar circulation?

Posterior communicating artery

Refer to the image below. Which ventricular structure is labeled as number 7 in this axial MR image?

Posterior horn of lateral ventricle

The branch of the vertebral artery that supplies the inferior cerebellum is the:

Posterior inferior cerebellar artery (PICA)

What is the function of the choroid plexuses?

Produces CSF

The functions of the mammillary bodies are:

Relay of impulses from the amygdala and hippocampus to the thalamus

Which of the following describes the functions of the pons?

Relays sensory information between the spinal cord, cerebellum, and cerebrum and has some function in controlling autonomic responses, such as respirations

The structure that separates the lateral ventricles is the:

Septum pellucidum

The dural sinus that is a continuation of the transverse sinus along the parietal, temporal, and occipital bones is the

Sigmoid

Sagittal MRI - Basal nuclei T2- weighted MR

Since the basal nuclei are made of gray matter, look for the lighter structures surrounded by darker white matter. The internal capsule is a thin strip of white matter that separates the thalamus from the lentiform nucleus

tonsils

Small prominence's on the inferior aspect of the cerebellar hemispheres

Which dural sinus is located at the junction of the falx cerebri and tentorium cerebelli?

Straight sinus

Parahippocampal gyrus

Structure that encloses the amygdala and hippocampus

There are three pairs of cerebellar peduncles:

Superior cerebellar peduncles - connect the cerebellum to the midbrain Middle cerebellar peduncles - connect the cerebellum to the pons Inferior cerebellar peduncles - connect the cerebellum to the medulla oblongata

Which of the following brainstem structures functions in coordinating eye movements with those of the head?

Superior colliculi

The portion of the cerebellum that connects it to the midbrain is the:

Superior peduncles

Which dural sinus is located at the superior border of the falx cerebri?

Superior sagittal sinus

A specialized sheath that connects all three portions of the brainstem is the:

Tegmentum

The division of the brain located inferior to the lateral fissure is the:

Temporal Lobe

Which dural fold separates the cerebrum from the cerebellum?

Tentorium cerebelli

The portion of the diencephalon that acts to transmit sensory impulses to the cerebral cortex is the:

Thalamus

MRA - Axial circle of Willis

The anterior communicating artery joins these two arteries at the top of the cerebral arterial circle. The middle cerebral arteries are seen laterally at this level.

What important function does the cerebral arterial circle (of Willis) serve?

The arterial circle provides collateral circulation in the event of an obstruction.

Axial MRI - Cerebral hemispheres

The bright CSF outlines the convoluted gyri bright white signal of the cerebrospinal fluid The longitudinal fissure is evident, running the length of the cerebrum, dividing it into the right and left cerebral hemispheres

MRI coronal - Gray & white matter

The cerebral cortex is comprised of gray matter and demonstrates darker in T1-weighted images. White matter comprises the deeper tissues and appears lighter in this image. The appearances of gray and white matter are reversed in T2-weighted MR images

Coronal MRI- Dural Folds

The definitive line between the two cerebral hemispheres is the dural fold, termed the "falx cerebri". The tentorium cerebelli is another dural fold, It is located between the inferior cerebral hemispheres and the superior cerebellum. The tentorium cerebelli acts as a divider between these two portions of the brain.

Sagittal MRI - Falx cerebelli & tentorium cerebelli

The dura, the outermost layer of the meninges, is labeled near the frontal lobe, but it is continuous around the entire central nervous system. The tentorium cerebelli is again seen in this image. It is easy to see how it separates the cerebellum from the cerebrum. The two cerebellar hemispheres are separated by the falx cerebelli, seen posterior to the cerebellum in this image.

What is the purpose of the dural folds?

The dural folds serve as partitions or dividers for portions of the brain.

Axial CT- Falx Cerebri

The falx cerebri is labeled at the anterior and lines the longitudinal fissure that divides the cerebrum into right and left hemispheres.

Axial MRI - Basal nuclei T2- weighted MR

The head of the caudate is the easiest to locate first since it lies adjacent to the anterior (frontal) horn of the lateral ventricle. The internal capsule is the thin band of white matter that separates the caudate nucleus from the lentiform nucleus. The lentiform nucleus is lateral to the internal capsule and is the larger, lighter structure in that region.

List the components of the limbic system

The hippocampus, amygdala, olfactory tracts, fornix, cingulate gyrus, and mammillary bodies are the components of the limbic system.

From which artery does the internal carotid artery arise?

The internal carotid artery arises from the bifurcation of the common carotid into the external and internal carotids.

What is the primary division of the cerebellum?

The lateral hemispheres are the primary division of the cerebellum.

Axial MRI - Medulla

The medullary cistern is just anterior, and cranial nerves IX and X can be seen near their insertion points on the patient's left side.

Coronal MRI - Pons

The pons is again seen, but now it is in the midline and inferior. The third ventricle is the slit-like, bright-white structure in about the middle of the image. The interventricular foramen (of Monroe) is also seen connecting the lateral ventricles to the third, but it is not labeled. The lateral ventricles are seen as well as their connecting structure, the corpus callosum. The fornix is also labeled at the end of the lateral ventricles. On each side of the pons, shaped like a sea horse, is the hippocampus of the limbic system.

Axial MRI - Pons

The pons is located almost in the middle of the image. The cerebellum is visible in the posterior portion, with the most inferior portions of the cerebrum seen in the anterior. The basilar artery is seen as the bright white dot just anterior and centered to the pons. The fourth ventricle, seen here as a dark hole, is on the posterior aspect of the pons.

Which artery branches from the basilar closest to the cerebral arterial circle (of Willis)?

The posterior cerebral artery (PCA) branches from the basilar artery almost at its junction to the posterior communicating artery.

Before the vertebral arteries unite, which arteries branch from each one?

The posterior inferior cerebellar arteries (PICA) branch from each vertebral artery prior to their anastomosis into the basilar artery.

MRA - Sagittal veins

This is a sagittal MRA image. Several vessels of the brain are labeled. Use this key to identify the labeled vessels: aca = anterior cerebral artery, ba = basilar artery, bv = basal vein of Rosenthal, ica = internal cerebral artery, icv = internal cerebral vein, sgs = sigmoid sinus, smcv = superficial middle cerebral vein, sts = straight sinus, ss = sagittal sinus, ts = transverse sinus, va = vertebral artery, vc = venous confluence, vg = vein of Galen.

CT - Circle of Willis

This is an axial CT image demonstrating the cerebral arterial circle

MRA - Axial veins

This is an axial MRA image. Several vessels of the brain are labeled. Use this key to identify the labeled vessels: bv = basal vein of Rosenthal, sgs = sigmoid sinus, sts = straight sinus, ts = transverse sinus, vc = venous confluence, vg = great cerebral vein (of Galen).

Axial MRI - Lateral & Third ventricle

Toward the posterior aspect, note the posterior, or occipital, horns of the lateral ventricles opening between the lateral ventricles and the third ventricle, the interventricular foramen

Ambient cistern

Tracks the lateral midbrain Connects the interpeduncular and quadrigeminal cisterns

Olfactory tract functions

Transmit the sense of smell, which is integrated into the limbic system

All of the following are pure motor nerves in function, except:

Trigeminal

The largest cranial nerve is the:

Trigeminal

Refer to the image below. Number 3 labels the:

White Matter

The accessory nerve is number:

XI

Fornix

a fiber tract that extends from the hippocampus to the mammillary body

The middle layer of the meninges is the:

arachnoid

Choroid plexuses

capillary bundles that project from the pia mater into the ventricles. produce cerebrospinal fluid

Circle of Willis

cerebral arterial circle, is located at the base of the brain, surrounding the sella turcica

Axial MRI - Midbrain

cerebral peduncles are labeled in the anterior midline of the brain. The white space in between the peduncles is the interpeduncular cistern.

Coronal MRI - Lateral ventricles

coronal T2-weighted MR image, so the cerebrospinal fluid is bright white and white matter demonstrates darker than gray matter. The fourth ventricle is of interest and is seen in the middle of the cerebellum as a thin slit of bright white due to the presence of cerebrospinal fluid

Coronal MRI - Medulla

coronal, T-1 weighted MR of the medulla oblongata and olives.

The space between the cranial bones and the meninges is the:

epidural

dentate nucleus

gray matter mass deep in white matter of arbor vitae

Medulla oblongata

medulla controls the vital functions of the body, such as respirations, heart rate, and blood pressure.

Review the midsagittal MR image below. What structure of the brainstem is labeled as number 7?

medulla oblongata

Midsagittal MRI - Brainstem

medulla oblongata is labeled. Just superior to it, the egg-shaped structure is the pons, with the midbrain sitting on top of it. Of note, the pituitary gland is labeled as the hypophysis cerebri in this image. The pineal body is also visible on the posterior aspect of the midbrain, shaped like a short worm.

White matter in the brain is composed of:

myelinated fibers

Which of the following is a pure sensory nerve in function?

optic

Review the coronal MR image below. What structure of the diencephalon is labeled as number 2?

pineal body

falx cerebri

separates cerebral hemispheres Lines the longitudinal fissure

What is the name of the space between the dura mater and arachnoid membrane?

subdural space

Thalamus (forms the lateral walls)

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Coronal MRI - Basal nuclei

the caudate nucleus is easily seen following the curve of the anterior horns of the lateral ventricles. The darker strip lateral to the caudate nucleus is the internal capsule. The next portion is lighter and is the putamen portion of the lentiform nucleus.

Axial CT - Fourth ventricle

the fourth ventricle is visible posterior to the pons

midsagittal MRI - Lateral ventricles 1

the frontal, or anterior, horns of the lateral ventricles as well as the occipital, or posterior, horns of the lateral ventricles.

Coronal MRI - Lateral & fourth ventricles

wing-shaped lateral ventricles