Oct9 M1-CNS Gross Anatomy Flashcards

1
Q

(IMP) meninges anat

A

surface to inside

  • dura mater: thick, white layer, consistency of leather
  • arachnoid mater: thin, semi-transparent. if present, obscures the sulci
  • pia mater: thin, transparent, not visible on gross inspection, covers the gyri and surrounds blood vessels as they penetrate the brain
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2
Q

subarachnoid space def

A

space between the arachnoid mater and the pia mater

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3
Q

leptomeninges def

A

pia mater + subarachnoid space + arachnoid mater.

  • arachnoid projects subarachnoid trabeculae across the subarachnoid space to contact the pia. (white shiny appearance)
  • will say leptomeningeal disease
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4
Q

pachymeninges def

A

dura mater

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5
Q

two layers of the dura mater

A

outer periosteal layer of dura (tightly attached to bone) and inner meningeal layer of dura (loosely attached to arachnoid)

  • stuck together at most places
  • not stuck together at midline on top of head
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6
Q

two potential spaces in the meninges (related to the dura)

A
  • epidural space = between skull and outer periosteal layer of dura
  • subdural space = between inner meningeal layer of dura and arachnoid
  • NONE OF THESE IS THE SPACE BETWEEN THE TWO LAYERS OF DURA*
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7
Q

pathologies of epidural space

A

epidural hematoma

  • one of the meningeal aa is damaged
  • blood accum in the epidural space
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8
Q

pathologies of subdural space

A

subdural hematoma

  • a blood vessel is damaged, usually a VEIN
  • blood accum there
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9
Q

dural projections def

A
  • periosteal and meningeal layers separate to make a projection
  • the meningeal layer goes to make a projection by following the brain
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10
Q

(IMP) 2 main dural projections

A
  • falx cerebri

- tentorium cerebelli

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11
Q

(IMP) falx cerebri def

A

inner meningeal layer projects between the two hemispheres at the midline on top of head
creates a vertical piece of dura in the cranial cavity

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12
Q

(IMP) tentorium cerebelli def

A

horizontal piece of dura from inner meningeal layer projecting between brain and cerebellum

  • creates a horizontal ‘‘tent’’ of dura, the cerebellum is under it*
  • tentorium adheres to the skull on both sides*
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13
Q

(IMP) clinical importance of the dural projections

A

increased ICP as in a tumor can cause part of the brain to be pushed down the falx and to ther other hemisphere or down past the tentorium

  • sub-falcine herniation
  • trans-tentorial herniation
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14
Q

(IMP) dural venous sinuses def

A

when the two layers of dura separate to form real spaces called dural venous sinuses (as in midline on top of head)

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15
Q

(IMP) superior sagittal sinus def

A

dural venous sinus in midline on top of head

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16
Q

how blood is drained from the dural venous sinuses

A

veins carrying blood away from the brain will take the blood from the dural venous sinuses

  • there are veins that drain in the venous sinuses
  • the venous sinuses then drain in the internal jugular vv
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17
Q

other example of dural venous sinus (other than superior sagittal sinus)

A

cavernous sinus

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18
Q

big hole in bottom of skull in the back

A

foramen magnum

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19
Q

how cavernous sinus relates to the pituitary gland

A
  • pituitary sits in small depression of the sphenoid bone of the skull called the sella turcica
  • the optic chiasm is on top of it
  • under the pit, there is bone covered by dura mater on top + on the sides
  • cavernous sinuses = the dural venous sinuses on both sides of this bone
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20
Q

what creates the cavernous sinus

A

the inner meningeal layer of the dura detaches from other periosteal layer of dura (which stays stuck to sphenoid bone in the bottom) and goes upwards medially

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21
Q

CNs relating to cavernous sinus

A

III, IV, V and VI

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22
Q

landmark separating the two hemispheres on top of the brain

A

longitudinal fissure (is the midline fissure)

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23
Q

bumps and depressions of the folds of the brain

A
  • bump = gyrus

- depression = sulcus

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24
Q

vertex of the head def

A

the upper part of the head and the brain

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25
Q

falx cerebri appearance on axial CT images of vertex vs base of brain

A

the fax cerebri starts on top of brain and ends at some distance after projection goes between the hemispheres. bc the brain has a curved shape, it follows this shape and ends a bit lower in the back and in the front of the cranial cavity

  • vertex = one continuous line
  • base of brain = in front and in back of brain only
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26
Q

para-falcine meningioma def

A

tumor of the meninges near the falx cerebri

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27
Q

(IMP) lobes of the cortex

A
  • frontal lobe (frontal half)
  • parietal lobe (two thirds of the posterior half (starting from middle on top)
  • occipital (last third of posterior half, in the very back)
  • temporal lobe (laterally on both sides) so have TWO temporal lobes
  • cerebellum lies under the brain in the back, under back of temporal and front of occipital lobes*
  • limbic lobe (cingulate gyrus) = band right under frontal lobe and parietal lobe
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28
Q

(IMP) major sulci of the LATERAL surface of the cerebral cortex

A
  • central sulcus (Rolandic fissure) between frontal and parietal lobes
  • Sylvian fissure (lateral sulcus) between frontal/parietal and temporal underneath (is almost horizontal)
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29
Q

(IMP) what is found underneath the Sylvian fissure (deep to it if push lobes away)

A

insula (insular cortex) (part of the cortex). imp in ANS

30
Q

(IMP) name of lobes parts covering the insula

A

frontal, parietal and temporal opercula (one = operculum)

31
Q

(IMP) primary vs association (secondary) cortical areas

A
  • primary = motor output originates there or sensory input directly comes there
  • association = things processed there before send motor output OR things processed there after receive sensory input
32
Q

(IMP) some important parts of the cortex and their anatomical landmark

A
  • frontal lobe gyrus = gyrus right anterior to central sulcus. is the PRIMARY MOTOR CORTEX (most UMNs originate there)
  • parietal lobe gyrus (gyrus right posterior to central sulcus). is the PRIMARY SENSORY CORTEX (OR SOMATOSENSORY CORTEX).
  • primary auditory cortex in the temporal lobe
33
Q

(IMP) example of important association cortical area and its anat landmark

A
  • a portion of the frontal lobe anterior to the frontal lobe gyrus
  • called PREMOTOR CORTEX. prepares info for movement
34
Q

how knowledge of brain areas fct was acquired

A

few cases of injuries and lesions and looked at what functions lacking

35
Q

one imp function of frontal lobe

A

personality

36
Q

(IMP) major sulcus of the MEDIAL surface of the brain

A

parietooccipital sulcus (between parietal and occipital lobes)

37
Q

(IMP) name of the region sitting right under the frontal and parietal lobes of the cortex

A

cingulate GYRUS (also called the limbic lobe)

  • memory
  • emotion
38
Q

(IMP) name of the region sitting right under the cingulate gyrus (limbic lobe)

A

corpus callosum

  • highway of white matter
  • between the two cerebral hemispheres
  • for axons passing between the two hemispheres*
39
Q

(IMP) ventral surface of the brain: landmarks

A

caudal to rostral

  • medulla (with pyramids = bumps formed by axons of corticospinal tract (CST))
  • pons
  • midbrain (with cerebral peduncles, part of it, contain the CSTs)
  • mamillary bodies (NOT part of midbrain)
  • pituitary gland with optic chiasm (X shaped underneath and a bit anterior)
  • optic chiasm gives off 2 optic tracts in the back
  • optic chiasm gives off two optic nerves in the front
  • olfactory tracts (CN I)
  • olfactory bulb (which is what the olfactory tracts become more anteriorly)
40
Q

fct of mamillary bodies

A

memory

41
Q

pathway the CSTs takes

A
  • primary motor cortex UMNs
  • through the brain
  • cerebral peduncles of midbrain
  • pons
  • medulla cross over in the lower medulla (called the pyramidal decussation. decussation = crossing)
42
Q

blood flow in brain

A

-internal carotid aa and vertebral aa
-circle of Willis at base of the brain
-aa and arterioles penetrate the brain
________________
-capillaries
-veins
-venous sinuses
-internal jugular veins

43
Q

(IMP) CSF flow in the brain

A
  • produced in choroid plexus (cells assoc with capillaries) in lateral ventricles + 3rd vent.
  • lat vent.
  • intraventricular foramenae of Monroe
  • 3rd vent.
  • cerebral aqueduct of Sylvius
  • 4th vent.
  • one midline foramen of Magendi and two lateral foramenae of Luschka
  • sub-arachnoid space
  • flows around the brain
  • reabsorbed by arachnoid villi
  • into venous sinuses
44
Q

4 spaces in the meninges

A
  • epidural space
  • dural venous sinuses
  • subdural space
  • subarachnoid space
45
Q

(IMP) what is found in the subarachnoid space

A
  • major aa of the brain
  • major vv of the brain before they drain in the dural venous sinus
  • CSF that exited the foramen of Magendie and the foramenae of Luschka
46
Q

how CSF from subarachnoid space ends up in dural venous sinuses

A

arachnoid villi project into the dural venous sinuses

are NOT the arachnoid trabeculae that were projecting to the pia

47
Q

what are the arachnoid villi

A

bulging of the arachnoid and the inner meningeal layer of dura into the dural venous sinus

48
Q

(IMP) hydrocephalus def

A

blocking of CSF circulation + ventricles get bigger as a result, because something blocks the reabsorption of fluid from subarachnoid space (communicating hydrocephalus) OR blocking flow of CSF in ventricular system (non-communicating hydrocephalus)

49
Q

(IMP) comm vs non comm hydrocephalus

A
  • comm = can reach all the brain bc no prob in circulation in vent. system
  • non comm = can’t reach rest of brain
50
Q

(IMP) ventricular enlargement in comm vs non comm

A
  • comm = ALL 4 ventricles enlarged
  • non-comm = 4th ventricle usually NOT enlarged bc it is rare that the obstruction obstructs all 3 foramenae after 4th ventricle (Magendie + 2 Luschka)
51
Q

(IMP) hydrocephalus causes classif

A
  • congenital (comm and non-comm)

- acquired (comm and non-comm)

52
Q

causes of congenital hydrocephalus

A
  • non comm: aqueduct stenosis, blood

- comm: absence of arachnoid villi, blood, pus

53
Q

causes of acquired hydrocephalus

A
  • non-comm: blood, tumor, pus

- comm: blood, pus

54
Q

how to detect hydrocephalus

A

measure head circumference

  • bones in newborn not fused yet so skull size reflects brain size (increased ventricular size will lead to increased skull and head size)
  • plot on normal size plot (growth charts) with percentiles
55
Q

tx of hydrocephalus (2)

A
  • ventriculoperitoneal shunt (tube) going through brain - lat ventricle - skull - subcu neck and trunk - peritoneum. prob = infection or shunt blocked
  • punch hole in 3rd ventricle (fluid flows directly in subarachnoid space)
56
Q

why hydrocephalus tx (radical) causes no prob at young age

A
  • brain plasticity at young age

- we have much more neurons at young age than we need

57
Q

shape of the lat ventricles

A

C

58
Q

name of lower part of the lat ventricles C shape

A

temporal horn

59
Q

how to know if it’s a comm or non-comm hydrocephalus on CT

A

check size of 4th ventricle

  • enlarged = comm
  • normal size = non-comm
60
Q

(not imp for now) main internal landmarks in the brain

A
  • thalamus
  • caudate and putamen
  • internal capsule and corpus callosum
  • amygdala, hippocampus and cingulate gyrus
  • hypoth and pituitary
61
Q

(not imp for now) thalamus charact

A
  • relay station for input to cerebral cortex
  • for info coming from cortex to elsewhere and from cerebellum (and elsewhere) to cortex
  • contains 3rd order sensory neurons (2nd order sensory neurons which has its nucleus in the brain synapses on it)
62
Q

(not imp for now) caudate and putamen charact

A
  • part of basal ganglia
  • group of interconnected nuclei
  • imp for planned motor activity like walking
  • discussed in PD
63
Q

(not imp for now) internal capsule and corpus callosum charact

A
  • both highways of axons in white matter
  • internal capsule = axons from or to cortex travel there (motor axons down or sensory axons up)
  • corpus callosum = axons passing between hemispheres travel there
64
Q

(not imp for now) amygdala, hippocampus and cingulate gyrus charact

A
  • part of limbic system

- imp for memory and attention

65
Q

(not imp for now) hypoth and pit charact

A
  • hypoth inferior to thalamus
  • fcts = homeostasis, sleep-wake cycle, ANS, hormonal
  • ant and post pit = hormones
66
Q

(not imp for now) internal brain landmarks seen in MRI axial cut at level where see internal capsule, frontal and occipital (front and back) horns of lat ventricles

A
  • head of caudate nucleus, post to frontal horn
  • putamen, post lat to head of caudate
  • internal capsule, white medial to putamen
  • thalamus, ant to occipital horn
67
Q

(not imp for now) internal brain landmarks seen in MRI axial cut at level of medial temporal lobe

A
  • midbrain in middle with CA in it bit post to middle
  • 2 hippocampus lat to it (most medial part of temporal lobe)
  • amygdala (ant to hippocampus)
  • cerebral peduncle (white of midbrain, between very middle of midbrain and hippocampus)
68
Q

(not imp for now) coronal section through lat ventricles at level of anterior temporal lobe see what

A
  • caudate nucleus lat to the lat ventricles
  • putamen lat to the caudate
  • connections between them
69
Q

(not imp for now) coronal section through lat ventricles at level of middle temporal lobe see what

A
  • third vent under the lat vents
  • thalamus lat to 3rd vent
  • hypoth inf and lat to 3rd vent
  • hippocampus inf and lat to hypoth
70
Q

(not imp for now) midline sagittal section of brain main internal landmarks

A
  • cingulate gyrus (right above corpus callosum easily visible
  • corpus callosum
  • pituitary gland (post to bottom of frontal lobe)
  • midbrain, pons, medulla
  • 4th vent behind bons
  • cerebellum behind 4th vent.