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
2
Q
subarachnoid space def
A
space between the arachnoid mater and the pia mater
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
4
Q
pachymeninges def
A
dura mater
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
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*
7
Q
pathologies of epidural space
A
epidural hematoma
- one of the meningeal aa is damaged
- blood accum in the epidural space
8
Q
pathologies of subdural space
A
subdural hematoma
- a blood vessel is damaged, usually a VEIN
- blood accum there
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
10
Q
(IMP) 2 main dural projections
A
- falx cerebri
- tentorium cerebelli
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
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*
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
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)
15
Q
(IMP) superior sagittal sinus def
A
dural venous sinus in midline on top of head
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
17
Q
other example of dural venous sinus (other than superior sagittal sinus)
A
cavernous sinus
18
Q
big hole in bottom of skull in the back
A
foramen magnum
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
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
21
Q
CNs relating to cavernous sinus
A
III, IV, V and VI
22
Q
landmark separating the two hemispheres on top of the brain
A
longitudinal fissure (is the midline fissure)
23
Q
bumps and depressions of the folds of the brain
A
- bump = gyrus
- depression = sulcus
24
Q
vertex of the head def
A
the upper part of the head and the brain
25
falx cerebri appearance on axial CT images of vertex vs base of brain
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
26
para-falcine meningioma def
tumor of the meninges near the falx cerebri
27
(IMP) lobes of the cortex
- 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
28
(IMP) major sulci of the LATERAL surface of the cerebral cortex
- central sulcus (Rolandic fissure) between frontal and parietal lobes
- Sylvian fissure (lateral sulcus) between frontal/parietal and temporal underneath (is almost horizontal)
29
(IMP) what is found underneath the Sylvian fissure (deep to it if push lobes away)
insula (insular cortex) (part of the cortex). imp in ANS
30
(IMP) name of lobes parts covering the insula
frontal, parietal and temporal opercula (one = operculum)
31
(IMP) primary vs association (secondary) cortical areas
- 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
(IMP) some important parts of the cortex and their anatomical landmark
- 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
(IMP) example of important association cortical area and its anat landmark
- a portion of the frontal lobe anterior to the frontal lobe gyrus
- called PREMOTOR CORTEX. prepares info for movement
34
how knowledge of brain areas fct was acquired
few cases of injuries and lesions and looked at what functions lacking
35
one imp function of frontal lobe
personality
36
(IMP) major sulcus of the MEDIAL surface of the brain
parietooccipital sulcus (between parietal and occipital lobes)
37
(IMP) name of the region sitting right under the frontal and parietal lobes of the cortex
cingulate GYRUS (also called the limbic lobe)
- memory
- emotion
38
(IMP) name of the region sitting right under the cingulate gyrus (limbic lobe)
corpus callosum
- highway of white matter
- between the two cerebral hemispheres
* for axons passing between the two hemispheres*
39
(IMP) ventral surface of the brain: landmarks
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
fct of mamillary bodies
memory
41
pathway the CSTs takes
- 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
blood flow in brain
-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
(IMP) CSF flow in the brain
- 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
4 spaces in the meninges
- epidural space
- dural venous sinuses
- subdural space
- subarachnoid space
45
(IMP) what is found in the subarachnoid space
- 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
how CSF from subarachnoid space ends up in dural venous sinuses
arachnoid villi project into the dural venous sinuses
| are NOT the arachnoid trabeculae that were projecting to the pia
47
what are the arachnoid villi
bulging of the arachnoid and the inner meningeal layer of dura into the dural venous sinus
48
(IMP) hydrocephalus def
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
(IMP) comm vs non comm hydrocephalus
- comm = can reach all the brain bc no prob in circulation in vent. system
- non comm = can't reach rest of brain
50
(IMP) ventricular enlargement in comm vs non comm
- 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
(IMP) hydrocephalus causes classif
- congenital (comm and non-comm)
| - acquired (comm and non-comm)
52
causes of congenital hydrocephalus
- non comm: aqueduct stenosis, blood
| - comm: absence of arachnoid villi, blood, pus
53
causes of acquired hydrocephalus
- non-comm: blood, tumor, pus
| - comm: blood, pus
54
how to detect hydrocephalus
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
tx of hydrocephalus (2)
- 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
why hydrocephalus tx (radical) causes no prob at young age
- brain plasticity at young age
| - we have much more neurons at young age than we need
57
shape of the lat ventricles
C
58
name of lower part of the lat ventricles C shape
temporal horn
59
how to know if it's a comm or non-comm hydrocephalus on CT
check size of 4th ventricle
- enlarged = comm
- normal size = non-comm
60
(not imp for now) main internal landmarks in the brain
- thalamus
- caudate and putamen
- internal capsule and corpus callosum
- amygdala, hippocampus and cingulate gyrus
- hypoth and pituitary
61
(not imp for now) thalamus charact
- 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
(not imp for now) caudate and putamen charact
- part of basal ganglia
- group of interconnected nuclei
- imp for planned motor activity like walking
- discussed in PD
63
(not imp for now) internal capsule and corpus callosum charact
- 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
(not imp for now) amygdala, hippocampus and cingulate gyrus charact
- part of limbic system
| - imp for memory and attention
65
(not imp for now) hypoth and pit charact
- hypoth inferior to thalamus
- fcts = homeostasis, sleep-wake cycle, ANS, hormonal
- ant and post pit = hormones
66
(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
- 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
(not imp for now) internal brain landmarks seen in MRI axial cut at level of medial temporal lobe
- 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
(not imp for now) coronal section through lat ventricles at level of anterior temporal lobe see what
- caudate nucleus lat to the lat ventricles
- putamen lat to the caudate
- connections between them
69
(not imp for now) coronal section through lat ventricles at level of middle temporal lobe see what
- 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
(not imp for now) midline sagittal section of brain main internal landmarks
- 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.
