NEURO 5 Flashcards
Cervicomedullary junction
occurs at level of foramen magnum, where spinal cord meets medulla
anterior fossa
contains frontal lobe, seperated by lesser wing of sphenoid
middle fossa
contains temporal lobe separated by petrous ridgee and sheet of meninges
posterior fossa
contains cerebellum and brainstem
SCALP
skin CT aponeurotica loose CT pericranium = periosteum
2 fibrous layers of dura
periosteal - inner surface of skull
meningeal layer - inner layer
Falx cerebri
sheet of dura from roof of cranium that seperates Right and left
tentorium cerebelli
covers upper surface of cerebellum
Midbrain passes through tentorium cerebelli via
tentorial incisura/notch
epidural space
potential space located between inner surface of skull and tightly adherent dura
Middle meningeal artery enters skull through
foramen spinosum
middle meningeal artery is branch of
external carotid
middle cerebral artery is branch of
internal carotid
subdural space
potential space between dura and arachnoid
Bridging veins transverse which space
subdural
subarachnoid space
CSF filled space between arachnoid and pia
dural sinuses drain
sigmoid sinuses to internal jugular veins
Frontal horn of lateral ventrical begins
foramen of monro
location of lateral ventricles
within the cerebral hemisphere
Atrium of lateral ventricle
at convergence w/ occipital horn, temporal horn and lateral ventricle
Third ventricle location
thalamus and hypothalamus
Fourth ventricle location
pons, medulla, cerebellum
How does the third ventricle communciate w/ fourth ventricle
cerebral aqueduct = aqueduct of sylvius
2 foramina CSF levels through
lateral foramina of Luschka
midlien foramen of Magendie
CSF is reabsorbed by
arachnoid granulations, arachnoid villus cells mediate one-way bulk transport
normal total volume of CSF
150 cc
how fast is CSF produced
20 cc/hours
150 cc/day
ambient cistern
lateral to midbrain
quadrigeminal cistern
posterior to midbrain
interpeduncular cistern
ventral surface of midbrain
3rd nerve exits midbrain through
interpeduncular fossa/cistern
prepontine cistern
ventral to pons
what is contained within prepontine cistern
basilar artery and 6th nerve
cistern magna
cerebellomedullary, largest located beneath cerebellum near foramen magnum
lumbar cistern
contains cauda equina, site for lumbar puncture
What permeates across BB easily
lipid-soluble substances, O2, CO2
Brain is interrupted in specialized regions called
circumventricular organs, allows changes in remaining body to seep through
Includes median eminence and neurohypophysis
are postrema
paired circumventricular organ, along caudal wall of fourth ventricle in medulla = chemotactic trigger zone
pineal
involved in melatonin-related circadian rhythms
vasogenic edema
excessive extracellular fluid
cytotoxic edema
intracellular fluid accumulation
normal intracranial pressure
<15 mm Hg
Transtentorial herniation
middle temporal lobe - uncus through tentorial notch
blown pupil, hemiplegia, coma
blown pupil IL, hemiplegia usually CL
Kernohan’s phenomenon
occurs in transtentorial herniation, CL corticospinal tract is compressed, causes IL hemiplegia
Central herniation
Central downward displacement of brainstem, associated with increased intracranial pressure, pushes on abducens nerve
lateral rectus palsy, bilateral uncal herniation
Tonsillar herniation
cerebellar tonsils downard through foramen magnum, associated w/ compresseion of medulla = respiratory arrest, blood pressure instability, death
Subfalcine herniation
unilateral mass lesion can cause cignulate gyrus to herniate beneath the falx cerebri
Epidural hematoma Location Cause clinical features Radiologic appearance
between dura and skull = potential
rupture of middle meningeal artery
can be lucid, leads to herniation and death
looks like biconvex disc along border
Subdural hematoma Location Cause clinical features Radiologic appearance
potential space between dura and arachnoid
rupture of bridging veins
Chronic: elderly, vague headaches, cognitive impairment, unsteady gait, focal seizures
Acute: high impact
forms cresent shaped hematoma
Radiologic of acute subdural hematoma
Hyperdense
Isodense 1-2 weeks
hypodense 3-4 weeks
mixed bleeding - occassional bleeding
hematocrit effect
subural hematoma w/ mixed density hematoma causing acute blood to settle to the bottom
Subarachnoid hemorrhage Location Cause clinical features Radiologic appearance
CSF space between arachnoid and pia
non traumatic: worst headache of my life, rupture of aneurysm or AVM, includes saccular/berry aneurysms
PComm aneurysm can cause third nerve palsy
normally causes nuchal rigidity, headache, photophobia, impaired consciousness , vasospasm
traumatic: severe headaches
blood in sulci following contours of pia
Mostc ommon locations of berry aneurysms
AComm = 30% Pcomm = 25% MCA = 20% vertebrobasilar system = 15% fusiform aneurysm (main vessel itself)
what should be performed before lumbar puncture
CT, if increased pressure, removal of CSF can increase bleeding
when testing for subarachnoid hemorrhage how should CT be performed
without contrast
Triple H therapy
for subarachnoid hemorrhage
hypertension
hypervolemia
hemodilution
Intracerebral or intraparenchymal hemorrhage Location Cause clinical features Radiologic appearance
within brain parenchyma
traumatic: contusions in temporal or frontal poles
nontraumatic: hypertention (most common), brain tumors, secondary hemorrhage, vascular malformations, blood coagulation abnormalitis, infections
coup injury
contusion on side of impact
contrecoup injury
contusion on opposite side of impact
what 2 factors increase chance of hypertensive hemorrhage
lipohyainosis
microaneurysms of Charcot-Bouchard
Most common location of hypertensive hemorrhage
basal ganglia, thalaus, cerebellum, pons
where does bleeding occur in lobar hemorrhage
occipital, parietal, temporal or frontal lobe
most common cause of lobar hemorrhage
amyloid angiopathy
cavernomas
abnormally dilated vascular cavities lined by one layer of vascular endothelium
Hemorrhage in ___ results in Battle’s sign
subcutaneous tissues
hemorrhage in ___ results in goose egg = subgaleal hemorrhage
external periosteum and galea aponeurotica
CSF for Acute Bacterial meningitis
WBC
Protein
Glucose
increased w/ polymorphonuclear leukocytes
increased
reduced
CSF for Viral+ Aseptic meningitis
WBC
Protein
Glucose
increased w/ lymphocytes
increased
normal
CSF for herpes meningoencephalitis
WBC
Protein
Glucose
increased or decreased, usually lymphocytes
increased
normal or reduced
CSF for tuberculous meningitis
WBC
Protein
Glucose
increased, usually lymphocytes
increased
reduced
