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Flashcards in Meninges And Blood Flow Deck (30):
1

CSF Functions

Provides buoyancy to protect against sudden movements

Constant pressure

Antibacterial

Controls extracellular fluid of brain

Clears waste and toxins during sleep

2

Circumventricular organs

Regions where the blood-brain barrier is interrupted so that brain can respond to changes in blood chemistry

3

Meninges in order

Outside in:
Dura (periosteal, meningeal)
Arachnoid
Pia

4

Cisterns

Enlarged subarachnoid space where CSF collects

5

Lumbar puncture is contraindicated if there is increased intracranial pressure because

If there is a mass in the brain, do not want to pull fluid because it could cause a vacuum and thus herniation of brain

6

Lumbar puncture in adults vs. children

In adults: L3-L4
In children: L4-L5

Difference is because spinal cord is goes down to further vertebrae in children than in adults. Changes as child grows.

7

Falx cerebri

Inner dural fold separating cerebral hemispheres

8

Falx cerebelli

Inner dural fold separating two hemispheres of cerebellum

9

Tentorium cerebelli

Inner dural fold separating the posterior cerebral hemispheres and the cerebellum

10

Posterior fossa

Cavity formed by occipital bone as base and tentorium cerebelli as roof, which contains the cerebellum and the brainstem

11

Tentorial notch

Narrow opening in tentorium cerebelli where midbrain passes through

12

Epidural hematoma

usually caused by trauma causing the middle meningeal artery to break

Period of lucidity before brain herniation

Lens shape on MRI

13

Subdural hematoma

Retraction of brain (in older people) puts tension on bridging veins, which may cause them to rupture

Crescent shape on MRI

14

Subarachnoid hemorrhage

Bleeding into subarachnoid space usually due to trauma

In non-trauma cases, cased by A-V malformation or ruptured aneurysm

Sudden onset of severe headache

15

Most common site of aneurysm

Branch points of arteries

In men: anterior communicating artery

In women: posterior communicating artery

16

Causes of increased intracranial pressure

Tumor
Hemorrhage
Abscess
Edema
Hydrocephalus
Infection

17

Symptoms of Increased Intracranial pressure

Headache
Altered mental status
Nausea, vomiting
Downward looking eyes
Papilledema
Visual loss
Diplopia
Cushing's triad
Skull expansion (in children)

18

Cushing's triad

Symptom of increased intracranial pressure

Causes hypertension, bradycardia, and irregular respirations

19

Transtentorial and Central Herniation

Aka uncal herniation

Uncus of temporal lobe herniates through tentorial notch

Triad of symptoms: blown pupil (ipsilateral), hemiplasia (contralateral), and coma

Pupillary response due to the compression of CN III

Coma if there is distortion of midbrain reticular formation that impairs consciousness

20

Subfalcine herniation

Herniation of parts of brain under the falx cerebri

21

Tonsillar herniation

Cerebrum herniates through foramen magnum, compressing the medulla, which may lead to respiratory arrest, blood pressure instability, and death

22

Hydrocephalus definition and types

When there is excess CSF due to overproduction (tumor in choroid plexus), obstructed flow in the ventricles or subarachoid space, or decreased reabsorption by arachnoid granules.

Communicating hydrocephalus: lateral ventricles can still communicate with subarachnoid space

Non-communicating hydrocephalus: flow is obstructed within the ventricular system

23

Symptoms of hydrocephalus

Headache (especially in the morning because CSF is resorbed less efficiently when lying down)

Neck pain

Decreased cognitive function

Vomiting

Papilledema

Drowsiness

Failure to upward gaze

24

Ventriculoperitoneal shunt

Tube inserted surgically to let CSF drain out of brain and into abdomen where body can resorb it in order to prevent hydrocephalus and brain damage.

25

Chairi malformation

Congenital hindbrain abnormalities associated with downward displacement of cerebellum, brainstem, or craniocervial junction

Causes hydrocephalus because CSF cannot flow through foramen magnum due to compression

Most have a genetic basis

26

Chairi Malformation I

Most common

Cerebellar tonsils dip below foramen magnum

Causes sringomyelia and compression of brainstem

Symptoms include headache, ataxia, and impaired movement

27

Chairi II

Aka Arnold chairi malformation

Less common

Significant hernia through foramen magnum causing aqueductal stenosis and hydrocephalus

Usually with meningomyocele

28

Normal pressure hydrocephalus

Cause not totally understood: could be due to impaired reabsorption or subarachnoid hemorrhage

Classical triad of symptoms: gait disturbance, dementia, urinary incontinence

29

Anterior circulation arises from ...

Internal carotid

30

Posterior circulation arises from ...

Vertebral artery