Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
150 Cards in this Set
- Front
- Back
|
what is contained in the posterior fossa |
cerebellum and brainstem
|
|
|
what divides the anterior and middle fossas
|
lesser wing of sphenoid
|
|
|
what divides the middle and posterior fossas
|
petrous portion of temporal bone and a sheet of meninges (tentorium cerebelli)
|
|
|
layers of the scalp
|
SCALP: skin, CT (subcutaneous), Aponeurotica, Loose areolar CT, Pericranium (periosteum)
|
|
|
two layers of dura
|
outer periosteal layer adherent to inner surface of skull and meningeal layer
|
|
|
where does the meningeal layer of dura fold in away from the periosteal layer
|
falx cerebri, tentorium cerebelli
|
|
|
3 spaces/potential spaces that the meninges form
|
1) epidural space 2) subarachnoid space 3) subdural space
|
|
|
epidural space
|
potential space btwn inner skull surface and dura
|
|
|
where does the middle meningeal artery enter the skull
|
via foramen spinosum and runs in epidural space; supplies dura
|
|
|
subdural space
|
potential space btwn the inner layer of dura and loosely adherent arachnoid
|
|
|
what do the bridging veins transverse
|
subdural space; drain cerebral hemispheres and pass through subdural space on the way to dural venous sinuses
|
|
|
what do dural sinuses drain to
|
sigmoid sinuses to reach internal jugular veins
|
|
|
what do blood vessels in general travel through in the brain
|
subarachnoid space, then send penetrating branches inward through pia
|
|
|
cells lining the ventricles
|
ependymal cells
|
|
|
what are the walls of the third ventricle formed by
|
thalamus and hypothalamus
|
|
|
how do the lateral ventricles communicate with the 3rd ventricle
|
interventricular forament of Monro
|
|
|
how does the 3rd ventricle communicate with the 4th ventricle
|
cerebral aqueduct traveling through midbrain
|
|
|
roof and floor of the 4th ventricle
|
cerebellum and pons/medulla
|
|
|
foramena that CSF leaves from 4th ventricle
|
lateral foramina of Luschka and midline foramen of Magendie
|
|
|
total CSF volume in an adult and production
|
150 cc; 20 cc/hour or 500 cc/day
|
|
|
cisterns within subarachnoid space
|
perimesencephalic (ambient, quadrigeminal, interpeduncular), prepontine, cisterna, and lumbar
|
|
|
where is the ambient cistern
|
lateral to midbrain
|
|
|
where is the quadrigeminal cistern
|
posterior to the midbrain; quad from the four bumps of superior and inferior colliculi
|
|
|
interpeduncular cistern/fossa location
|
ventral surface of midbrain btwn cerebral peduncles
|
|
|
what CN exits the midbrain through the interpeduncular fossa
|
CN III
|
|
|
what is located in the prepontine cistern
|
basilar artery and CN VI
|
|
|
what substances can readily cross the cell membranes of blood-brain and blood-CSF barriers
|
lipid soluble, inculding CO2 and O2
|
|
|
how large are arachnoid vilus cells bulk transport abilities
|
large enough to engulf entire RBCs
|
|
|
circumventricular organs
|
blood-brain barrier interupted allowing brain to respond to changes in chemical milieu of remainder of body
|
|
|
where are circumventricular organs located
|
median eminence and neurohypophysis - regulate and release pituitary hormones; also subfornical organ, pineal, subcommissural organ, area postrema, and organum vasculosum
|
|
|
where is the area postrema
|
caudal wall of 4th ventricle in medulla; aka chemoactic trigger zone
|
|
|
what may be the fxn of organum vasculosum and lamina terminalis
|
neuroendocrine fxns
|
|
|
what fxn may the subfornical organ have
|
fluid balance regulation
|
|
|
what can disrupt the blood-brain barrier
|
brain tumors, infections, and others
|
|
|
vasogenic edema
|
excessive extracellular fluid
|
|
|
cytotoxic edema
|
fluid accumulation within cells
|
|
|
innervation of the dura
|
supratentorial dura by CN V; posterior fossa CN X (and some by CN IX and 1st 3 cervical nerves
|
|
|
firtification scotoma
|
characteristic region of visual loss bordered by zigzagging lines resembling the walls of a fort; may be part of migrain aura
|
|
|
complicated migraine
|
accompanied by a variety of transient neurologic deficits like senory phenomenon, motor deficits, visual loss, brainstem findings in basilar migraine, impaired eye movements in opthalmoplegic migraine
|
|
|
what should be ruled out if sudden explosive headache occurs
|
subarachnoid hemorrhage via CT scan
|
|
|
what affect does low CSF have on headache
|
headache worse standing up than laying down
|
|
|
increased intracranial P and headache
|
worse laying down during night
|
|
|
pseudotumor cerebri
|
headache and elevated ICPs with no mass lesion
|
|
|
temporal arteritis aka giant cell arteritis
|
vasculitis affects temporal arteries and other vessels (enlarged and firm)
|
|
|
how is temporal arteritis diagnosed
|
erythrocyte sedimentation rate (ESR) and tempoeral artery biopsy
|
|
|
when should meningitis be suspected and immediately tested for and treated
|
headache with fever or meningeal irritation like stiff neck and sensitivity to light
|
|
|
how do intracranial masses cause neurologic symptoms and signs
|
1) compression and destruction of adjacent regions 2) intracranial P increase 3) displace nervous system structures - herniation
|
|
|
mass effect
|
any distortion of normal brain geometry due to mass lesion
|
|
|
cerebral perfussion P
|
mean arterial P minus ICP
|
|
|
projectile vomiting
|
occurs suddenly and without much nausea
|
|
|
signs of elevated ICP
|
headache, decreased alertness and attention, nausea and vomiting, papilledema
|
|
|
how quickly does papilledema dvlp
|
several days and is often not present in an acute setting
|
|
|
what can diplopia result from
|
downward traction on CN VI
|
|
|
Cushing's triad
|
hypertension, bradycardia, and irregular respirations; sign of increased ICP
|
|
|
normal adult ICP
|
less than 20 cm water or less than 15 mm Hg (torr)
|
|
|
what should cerebral perfusion P be kept above
|
50 mm Hg
|
|
|
transtentorial herniation
|
herniation of medial temporal lobe, especially uncus
|
|
|
uncal herniation clinical triad
|
blown pupil, hemiplegia, coma
|
|
|
what causes a blown pupil
|
compression of CN 3, usually ipsilateral to the lesion
|
|
|
what causes hemiplegia
|
compression of cerebral peduncles
|
|
|
Kernohan's phenomenon
|
countralateral corticospinal tract compressed due to uncal herniation of midbrain being pushed against opposite side of tentorial notch, ipsilateral loss since tracts haven't crossed yet
|
|
|
central herniatin
|
central downward displacement of brainstem; can cause traction of CN VI
|
|
|
tonsillar herniation
|
herniation of cerebellar tonsils downward through the foramen magnum
|
|
|
subfalcine herniation
|
cingulate gyrus and other brain structures herniate under falx cerebri
|
|
|
what infarcts can occur due to subfalcine herniation
|
anterior cerebral artery infarcts
|
|
|
what infarcts can occur due to uncal herniation
|
posterior cerebral artery herniation
|
|
|
concussion
|
reversible impairment of neurological fa=xn after minutes to hours following head injury
|
|
|
postconcussive syndrome
|
headaches, lethargy, mental dullness, and other symptoms up to several months after accident
|
|
|
severe head trauma causes brain injury via what mechanisms
|
1) diffuse axonal shear injury 2) petechial hemorrhages 3) intracranial hemorrhages 4) cerebral contusion 5) penetrating trauma 6) cerebral edema
|
|
|
types of intracranial hemorrhage
|
1) epidural (EDH) 2) subdural (SDH) 3) subarachnoid (SAH 4) intracerebral or intraparenchymal (ICH)
|
|
|
epidural hematoma usual cause
|
rupture of middle meningeal artery due to fracture of temporal bone by head trauma
|
|
|
epidural hemorrhage image on CT
|
lens-shaped convexity that doesn't spread past cranial sutures
|
|
|
subdural hematoma usual cause
|
rupture of bridging veins which are vulnerable to shear injury as they cross from arachnoid into dura
|
|
|
subdural image on CT
|
crescent-shaped hematoma over large area
|
|
|
chronic subdural hematoma
|
generally in elderly; slow oozing, blood collects over weeks/months
|
|
|
acute subdural hematoma
|
high impact velocity, generally occurs with subarachnoid and brain contusion
|
|
|
age and denseness of subdural hemotoma on imaging
|
new - hyperdense blood; 1-2 weeks isodense clot liquification; 3-4 weeks hypodense complete liquification; hematocrit effect - denser on bottom
|
|
|
subarachnoid hemorrhage image on CT
|
track down into the sulci following contrours of pia
|
|
|
subarachnoid hemorrhage general cause
|
nontraumatic and traumatic
|
|
|
nontraumatic subarachnoid hemorrhage
|
presents with worsening catastrophic headache; generally due to ruptured aneurysm, less often from AV malformation
|
|
|
where do most saccular/berry aneurysms occur
|
anterior circulation (carotids)- Anterior communicating 30%, posterior comm 25%, MCA 20%, vertebrobasilar system 15%
|
|
|
what can an unruptured Pcomm aneurysm arising from the internal carotid cause
|
painful 3rd nerve palsy
|
|
|
why is it important to NOT use contrast when checking for aneurysm
|
subarachnoid blood and contrast material both appear white on the scan, making small hemorrhages difficult to see
|
|
|
LP and aneurysms
|
only done if CT negative
|
|
|
where do contusions occur
|
side of impact (coup) and opposite side of impact (contrcoup) due to rebound
|
|
|
cause of intracerebral or intraparenchymal (ICH) nontraumatically
|
hypertension, brain tumors, secondary hemorrhage after ischemic infarction, cascular malformation, blood coagulation abnormalities, infectsions, veddel fragility due to amyloid, etc
|
|
|
what does hypertensice hemorrhage tend to involve
|
small penetrating blood vessels (basal ganglia, thalamus, cerebellum, then pons)
|
|
|
lobar hemorrhage
|
bleeding involves occipital, parietal, temporal, or frontal lobe; mast common is due to amyloid angiopathy
|
|
|
vascular malformation categories
|
1) AV malformations 2) cavernous malformations 3) capillary telangiectasias 4) venous angiomas
|
|
|
AV malformations
|
abnormal direct connections btwn arteries and veins
|
|
|
cavernous malformations
|
abnormally dilated vascular cavities lines by only one layer of vascular endothelium
|
|
|
capillary tangiectasias
|
small regions of abnormally dilated capillaries that rarely give rise to hemorrhage; usually incidental finding
|
|
|
extracranial hemorrhage
|
within ear, subcutaneous tissues
|
|
|
cephalohematoma
|
bleeding btwn skull and external periosteum in newborns
|
|
|
subgaleal hemorrhage aka goose egg
|
loose space btwn external periosteum and galea aponeurotica
|
|
|
what can cause excess CSF
|
overproduction, blockage, or slow reabsorption
|
|
|
what can cause excess production of CSF
|
rare, generally via tumor like choroid plexus papilloma
|
|
|
clinical dividions of hydrocephalus
|
communicating and noncommunicating
|
|
|
in mild or slowly dvlping cases of hydrocephalus what is seen
|
only a sixth nerve palsy may be seen
|
|
|
how can hydrocephalus affect gait
|
compress descending white matter trats from frontal lobes causing things like magnetic gait
|
|
|
Parinaud's syndrome
|
limited vertical gaze caused by dilation of the suprapineal recess of the posterior 3rd ventricle pushing down on the collicular plate of midbrain
|
|
|
external ventricular drain
|
fluid from lateral ventricles is drained into a bag outside the head
|
|
|
ventriculoperitoneal shunt |
shunt tube passing from lateral ventricle out of skull, tunneled under skin to peritoneal cavity
|
|
|
normal-pressure hydrocephalus
|
chronically dilated ventricles
|
|
|
clinical triad in normal-P hydrocephalus
|
gait difficulties, urinary incontinence, and mental decline
|
|
|
hydrocephalus ex vacuo
|
excess CSF in region of brain tissue lost as result of stroke, surgery, atrophy, trauma, or other insult |
|
|
where are CNS tumors located in adults and kids
|
adults: 70% supratentorial and 30% infratentorial; kids: 70% posterior fossa and 30% supratentorially
|
|
|
tumors commonly associated with seizures
|
oligodendrogliomas and meningiomas
|
|
|
menginiomas arise from
|
arachnoid villus cells; grow slow, appear as homogeneous enhancing areas arising from meningeal layers; associated with breast cancer |
|
|
pituitary adenomas
|
can compress optic chiasm
|
|
|
lymphoma arises from
|
B lymphocytes and commonly involved regions adjacent to ventricles
|
|
|
most common brain tumors of kids in posterior fossa
|
astrocytoma, medulloblastoma, and ependymoma
|
|
|
paraneoplastic syndromes
|
remote effects on brain/CNS from cancer of the body; most common in small cell cancinoma, breast cancer, and ovarian cancer
|
|
|
infectious meningitis
|
infection of CSF in suarachnoid space caused by viruses, bacteria, fungi, or parasites
|
|
|
features of meningeal irritation
|
headache, lethargy, sensitivity to light and noise, fever, nuchal rigidity
|
|
|
nuchal rigidity
|
neck muscles contract involuntarily resulting in resistance to active or passive neck flexion, accompanied by neck pain
|
|
|
acute bacterial meningitis
|
CSF high WBC count with polymorphonuclear predominance, high protein, low glucose
|
|
|
brain abscess
|
expanding intracranial mass lesion, like a tumor, but with a more rapid course; bacterial infection
|
|
|
epidural abscess in spinal cord presenting symptoms
|
back pain, fever, elevated WBC count, signs of nerve root or spinal cord compression
|
|
|
subdural empyema cause
|
collection of pus in subdural space generally from extension of infection in nasal sinus or ear
|
|
|
tuberculous meningitis cause
|
inflammatory response in basal cisterns of brain
|
|
|
Pott's disease
|
involvement of epidural space and vertebral bones
|
|
|
two most important spirochete infections in the nervous system
|
neurosyphilis and Lyme disease
|
|
|
aseptic meningitis cause
|
can be due to meningeal involvement associated with CN palsies (especially optic, facial, and vestibulocochlear)
|
|
|
meningovascular syphilis
|
chronic meningeal involvment causes arteritis that results in diffuse white matter infarcts
|
|
|
CSF in viral meningitis
|
elevated WBC count, lymphocytic predominance, normal or mildly elevated protein, normal glucose (polymorphonuclear predominance may be present in early stages)
|
|
|
viral encephalitis
|
involve brain parenchyma
|
|
|
herpes simplex
|
most common cause of viral encephalitis, tropism for limbic cortex
|
|
|
subacute sclerosing panencephalitis
|
delayed, slowly progressive fatal encephalitis; measles can cause
|
|
|
transverse myelitis
|
inflammatory response in the spinal cord
|
|
|
AIDS dementia complex
|
most common neurologic manifestation of HIV
|
|
|
highly active antiretroviral therapy (HAART)
|
azidothymidine (AZT) plus 3TC plus protease inhibitor
|
|
|
Progressive multifocal leukoencephalopathy (PML)
|
caused by a papovavirus called JC virus and results in gradual demyelination of the brain; usually leads to death within 3 to 6 months
|
|
|
what should be suspected in all HIV-pos patients with chronic headache
|
cryptococcal meningitis (fungal infection); antigen must be checked in CSF for diagnosis
|
|
|
most common cause of intracranial mass lesions in HIV positive patients
|
toxoplasmosis
|
|
|
second most common cause of inteacranial mass lesions in HIV positive patients
|
primary central nervous system lymphoma (B cell lymphoma); diagnosed via biopsy of CSF PCR for epstein-barr virus
|
|
|
cysticercosis cause
|
ingestion of eggs of pork tapeworm
|
|
|
cysticercosis effects
|
forms multiple small cysts in muscles, eyes, and CNS; seizures common result along with headache, nausea, vomiting, lymphocytic meningitis, and focal deficits
|
|
|
what occurs after cysticercosis organisms die
|
leave 1-3 mm calcifications scattered throughout brain (brain sand)
|
|
|
what fungus occasionally spreads from the nasal passages to the orbital apex causing apex syndrome
|
aspergillus
|
|
|
mucormycosis
|
fungal infection mainly of diabetics in rhinocerebral from and involves the orbital apex
|
|
|
what can exacerbate fungal infections
|
steroids
|
|
|
what are the main 2 fungi that infect brain parenchyma
|
aspergillus and candidia; accompanied by intense inflammatory response
|
|
|
prion pathology
|
diffuse degeneration of brain and spinal cord with multiple vacuoles resulting in spongyform appearance
|
|
|
presenting features of Creutzfeldt-Jakob disease
|
rapidly progressive dementia, exaggerated startle response, myoclonus, visual distortions, ataxia
|
|
|
what can impaired coagulation cause if a LP is performed
|
iatrogenic spinal epidural hematoma, which can compress cauda equina
|
|
|
what does the needle pass through in an LP
|
subcutaneous tissues, ligaments of spinal column, dura, and arachnoid mater
|
|
|
how can traumatic tap be distinguished from pathological subarachnoid hemorrhage
|
1) number of RBC decreases from 1st to last tubes in traumatic tap 2) when cnetrifuges, supernatant may have yellowish or xanthochromic appearance as result of hemorrhage , none in traumatic tap
|
|
|
when is a pterional craniotomy performed
|
anterior circulation and basilar tip aneurysms, cavernous sinus, and suprasellar tumors
|
|
|
suboccipital craniotomy is used with what structures
|
cerebellopontine angle, vertebral artery, brainstem, lower cranial nerves
|
