Lecture 1

Question 1

What are the 3 layers of the meninges?

Answer 1

Dura mater- thickest outermost later, protective, impermeable

Arachnoid mater- middle layer, impermeable, adjoins dura (not tightly bound), separated from pia by subarachnoid space that is filled with cerebrospinal fluid

Pia mater- delicate, permeable, innermost, resting on brain surface, adheres to every bit of brain, has massive fenestrations

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Question 2

What are the 2 sub categories of the dura mater?

Answer 2

1. Periosteal layer- attached to inner surface of skull
   Not continuous with dura mater
2. Meningeal layer- covers brain, folds inward to divide and support major parts of brain, continuous with dura mater of SC and epineurinum of cranial nerves

Both are closed united except at venous sinuses

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Question 3

What is the venous sinus?

Answer 3

Large, low pressure blood vessel return path for cerebral venous blood
Takes already deoxygenated blood and brings it back for oxygen

Question 4

What is falx cerebri?

What is the superior and inferior border?

Answer 4

Sickle shaped fold separating the cerebral hemispheres
Superior convex border forms floor of superior sagittal sinus
Inferior border houses inferior sagittal sinus

Function to restrict brain displacement

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Question 5

What is tentorium cerebelli?

Answer 5

Fits between the cerebellum and the occipital lobes; separates the posterior cranial fossa from the rest of the cranial vault
Arches upward along median line to become continuous with falx cerebri to form straight venous sinus

Function to restrict brain displacement

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Question 6

What is epidural space?

Hematoma?

Answer 6

Tight potential space between the dura and the skull
Caused by rupture of the middle meningeal artery during head trauma

Can bleed in this space (epidural hematoma)
Bleeds right under skull, dangerous cause no symptoms until pressure builds up

EPI means on top (on top and dura space)

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Question 7

What is subdural space?

Hematoma?

Answer 7

Potential space between the dura and the loosely adherent arachnoid
Caused by rupture of bridging veins that pass through en route to dura sinuses (vulnerable time sheer injuries)
Bleeds under dura but above arachnoid
Results in death more than epidural

Sub= under (under the dura)

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Question 8

What is acute and chronic subdural hematoma?

Answer 8

Acute can occurs with high velocity impact

Chronic seen in elderly where brain atrophy allows brain to move freely in cranial vault making bridging veins more likely to injure
Slow bleeding over weeks/months, brain accommodates so symptoms are vague

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Question 9

What area do all cerebral arteries and veins lie?

Answer 9

In the subarachnoid space, sending off branches that penetrate into the brain (aneurysm site, may hemorrhage)

Question 10

What are trabeculae?

What are arachnoid granulations?

Answer 10

Trabeculae are delicate threads that connect arachnoid to pia

Arachnoid granulations are the site where cerebrospinal fluid diffuses into the venous sinuses

Slide 9 lecture 1

Question 11

What are headaches and their role with the meninges?
What about migraines?
Cluster headache?

Answer 11

Pain comes from trigeminal and first 3 cervical nerves innervating the meninges and vasculature

Dura above tentorium innervated by trigeminal; forehead and face
Dura below tentorium innervated by C1-3 cervical; back of head and neck

Migraines depend of activation of the trigeminal afferents that densely innervate the meninges
Cluster headache lancinating or boring periorbital pain (most painful)

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Question 12

What is the breakdown of the vascular system in the brain?

2 circulations

Answer 12

Brain has tight regulatory control over delivery of O2, glucose and other nutrients, and removal of CO2
High metabolic rate, weighs 2% of body weight yet uses 20% total O2 and 25% glucose

Posterior circulation- basilar artery and vertebral artery

Anterior circulation- internal carotid artery (2 going up each side)

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Question 13

What is the anastomosis that protects brain?

Answer 13

It is the Circle of Willis that provides an overlapping blood supply
If one side gets blocked, then blood can still flow all the way around to other artery (protective mechanism)

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Question 14

What are the 2 anterior cerebral arteries connected to?

What are the posterior cerebral arteries connected to?

Answer 14

2 anterior cerebral arteries are connected by the anterior communicating artery

The posterior cerebral arteries are connected to the internal carotid arteries by the posterior communicating arteries

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Question 15

Memorize where the middle cerebral artery, anterior cerebral artery, and posterior cerebral artery are on slide 18 lecture 1

Answer 15

Each hemisphere devotes a carotid artery

Question 16

What is the anatomy and vascular territory of the middle cerebral artery?

Answer 16

Middle cerebral artery had superior and inferior divisions of cortical branches
Takes an indirect course through the lateral sulcus, along the insular cortex, and over the inner opercular surface of the frontal, temporal, and parietal lobes

MCA supplies most of lateral convexity of the cortex (except leg area of motor homunculus) and the white matter (includes frontal, parietal, temporal, and occipital lobes)

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Question 17

What is the anatomy and vascular territory of the anterior cerebral artery?

Answer 17

Anterior cerebral artery courses within the sagittal fissure and around the rostral end of the corpus callosum
Anterior cerebral artery supplies anterior

ACA supply the cortex and white matter of the medial frontal and parietal lobes, and the anterior corpus callosum

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Question 18

What is the anatomy and vascular territory of the posterior cerebral artery?

Answer 18

Posterior cerebral artery courses around the lateral part

PCA supply the occipital lobes and portions of the medial and inferior temporal lobes and the posterior corpus callosum

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Question 19

What are the 4 clinical vascular syndromes resulting from infarction within vascular territories involving the middle cerebral artery (MCA)?

Answer 19

1. Contralateral hemiparesis and hemisensory loss involving mainly the face and arm (precentral and postcentral gyri)
2. Hemineglect- (right hemisphere MCA) unawareness of space and patients own body contralateral to the lesion (patients seem unaware or deny handicap)
3. Anosognosia- (right hemisphere MCA) includes unawareness of quite dramatic impairments, such as blindness or paralysis
4. Aphasias- (left hemisphere MCA)

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Question 20

What are the 2 types of aphasias?

Answer 20

Broca’s aphasia- difficulty producing speech
Comprehension intact
Disordered grammar and syntax (meaningful phrases produced with great effort)

Wernicke’s aphasia- difficulty comprehending speech
Speech fluent, well structured
Syntax adequate but nonsensical

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Question 21

What is the 1 clinical vascular syndrome resulting from infarction within vascular territories involving the anterior cerebral artery (ACA)?

Answer 21

Contralateral hemiparesis- paralysis or weakness of one side of the body, and hemisensory loss involving mainly the leg and foot (paracentral lobule), personality changes (frontal lobe)

Question 22

What are the 5 clinical vascular syndromes resulting from infarction within vascular territories involving the posterior cerebral artery (PCA)?

Answer 22

1. Hemianopsia- (occipital PCA) loss of vision for one half of the visual field
2. Visual Agnosia- (occipital PCA) inability to recognize or interpret objects in the visual field
3. Memory impairment (temporal PCA)
4. Prosopagnosia- damage time the inferior temporal cortex (PCA targeted area), unable to identify facial characteristics, may not recognize face at all, aware that some visual stimulus is present, can describe some aspects without difficultly

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Question 23

What are these terms:
Stroke
Occlusive
Hemorrhagic 
Intraparenchymal hemorrhage 
Extraparenchymal hemorrhage

Answer 23

Stroke- death or dysfunction of brain tissue due to vascular disease
Occlusive- closure of blood vessel- atherosclerosis or thrombosis
Hemorrhagic- bleeding from a vessel- hypertension and aneurysm
Intraparenchymal hemorrhage- within the brain bleed
Extraparenchymal hemorrhage- at the brain surface bleed (subarachnoid)

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Question 24

Define these terms:
Hematoma
Embolus
Embolism
Aneurysm 
Ischemia 
Anoxia 
Infarction

Answer 24

Hematoma- accumulation of blood that clots
Embolus- material (blood clot, fat, air) carried from one point to lodge in another
Embolism- embolus becomes lodged in an artery and obstructs flow
Aneurysm- balloon-like swelling in the wall of an artery
Ischemia- insufficiency of blood supply
Anoxia- reduced oxygen supply
Infarction- neuronal death

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Question 25

What is the venous drainage of cerebral hemispheres (how blood leaves brain)?

Answer 25

Superficial veins drain into sup. Sagittal sinus and cavernous sinus
Deep veins drain into great vein of Galen
Superior Sagittal sinus drains into the 2 transverse sinuses which lead to the sigmoid sinus that connects to the jugular vein

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