Neuroanatomy Flashcards
1
Q
What is the corpus callosum?
A
It is the largest white matter tract in the body
Links the cerebral hemispheres
2
Q
What is the gross anatomy of the corpus callosum?
A
Has 4 key parts
rostrum
genu - links to forceps minor (frontal lobe)
body
splenium - links to forceps major (links occipital lobes)
3
Q
What are the relations of the corpus callosum?
A
Superior: cingulate gyrus
Inferior: septum pallucidium (anterior), fornix (posterior)
Laterally: radiation fibres - go to relative tracts
4
Q
What is the arterial supply of the corpus callosum?
A
Pericallosal arteries - from the anterior communicating artery
Posterior pericallosal arteries - from the posterior communicating artery
5
Q
What is the venous drainage of the corpus callosum?
A
unnamed veins - drain to inferior saggittal sinus
6
Q
What is the anatomical variation associated with the corpus callosum?
A
Corpus callosum agenesis - associated with maternal alcohol consumption
Can have arterial variants - minor arteries from anterior communicating - subcallosal A, median callosal A
Posterior pericallosal artery - from PCA, usually P3
7
Q
What is the circle of willis and function?
A
anastomosis on the underside of the brain
provides collateral circulation should one of the arteries become occluded
8
Q
Where does the circle of willis sit?
A
in the suprasellar cistern
9
Q
What are the relations to the circle of willis?
A
Superior - ventral surface of brain
Inferior - sella
Medial - hypothalamus and infundibulum
10
Q
What are the anatomical variants associated with the circle of willis?
A
only 20 percent of the population has a complete COW
Common arterial variants include;
- hypoplastic / absent ACA
- hypoplasia of one / both PCOMM
- Absent / fenestrated ACOMM
- Persistent primitive trigeminal artery
** PPTA is where the ICA leaves the carotid canal, about to enter cavernous sinus, and then runs along trigeminal N to join basilar A
11
Q
What are the subarachnoid cisterns?
A
Widenings of the subarachnoid space
12
Q
What is the function of the subarachnoid cisterns?
A
multiple structures traverse the subarachnoid cisterns
covered by a thin surface of pia mater
Can contain tonsils in herniation + blood in subarachnoid haemmorhage
13
Q
What is the gross anatomy of the suprasellar cistern?
A
Suprasellar cistern
- under the third ventricle, above the sella
- contains circle of willis, optic chiasm,
- is a core review area, as in SAH blood pools here
14
Q
What is the gross anatomy of the interpeduncular cistern?
A
Between the cerebral peduncles
contains the oculomotor nerve and basilar bifurcation
15
Q
What is the gross anatomy of the ambient cistern?
A
Around the midbrain
Contains the posterior communicating artery, P2 and trochlear nerve (CN 4)
16
Q
What is the gross anatomy of the quadrigeminal cistern?
A
posterior to the pineal gland, between splenium of corpus callosum but it is superior to the cerebellum
contains the great vein of galen and posterior communicating artery P3
17
Q
What is the gross anatomy of the prepontine cistern?
A
Between pons and clivus
Contains basilar artery
18
Q
What is the gross anatomy of the premedullary cistern?
A
Between pontomedullary junction and foramen magnum
Contains vertebral artery, anterior spinal artery, posterior inferior cerebellar artery, hypoglossal nerve
19
Q
What is the gross anatomy of the cisterna magna?
A
between cerebellum and foramen magnum
contains the cerebellar tonsils
important to review this area to check for tonsil herniation, chiari malformation
20
Q
What are the 7 segments of the internal carotid artery?
A
cervical
petrous
lacerum
cavernous
clinoid
opthalmic
communicating
21
Q
What is the gross anatomy of the internal carotid artery?
A
Origin: from the carotid bifurcation at C3, ECA usually arises anteriorly and medially
7 segments:
cervical, petrous, lacerum, cavernous, clinoid, opthalmic, communicating
22
Q
What are the arteries which come off each segment of the internal carotid artery?
A
Cervical
Petrous - vidian artery (ECA anastomosis), cardiotympanic artery
Lacerum
Cavernous - inferolateral trunk (ECA anastomosis) meningohypophyseal trunk
Clinoid
Opthalmic - opthalmic artery
Communicating - posterior communicating artery, ACA + MCA, anterior choroidal artery
terminates as MCA + ACA
23
Q
What are the relations of the internal carotid artery?
A
Petrous ICA - intimately related to middle ear, inner ear
Cavernous ICA - has abducens nerve immediately inferolaterally
Lacerum ICA - has trigeminal N overlying it
24
Q
What are the variants associated with internal carotid artery?
A
kissing carotids - tortuous course of carotids, can be in retropharynx or sphenoid, huge implications for sphenoidal / pharyngeal A
abberant petrous ICA - ICA goes posterolaterally, so creates a pulsatile retrotympanic mass
persistent trigeminal A - artery from ICA which connects to basilar A
congenital absence!!
25
What is the anterior cerebral artery?
One of the terminal branches of the ICA
Supplies the medial brain
26
What is the gross anatomy of the anterior cerebral artery?
Origin: smaller, anterior terminal division of the ICA
Course: 3 segments:
- A1 Horizontal - runs through supracellar cistern, superior to optic nerve
- A2 Vertical - anterior to third ventricle and rostrum of corpus callosum
- A3 Distal - curves around corpus callosum genu
terminates as the pericallosal artery (which wraps around the corpus callosum)
27
What does the anterior cerebral artery supply?
medial brain (as far posteriorly as the parieto occipital surface)
28
What are the branches of the anterior cerebral artery?
anterior communicating artery - which link the two A1 segments
recurrent artery of heubner - biggest perforating branch from the proximal ACA (Can be seen on DSA!)
orbitofrontal artery
frontopolar artery
collosomarginal artery
pericallosal A (distal most continuation of ACA)
29
What are the anatomical variants of the anterior cerebral artery?
azygos ACA - ACA is fused to form a common trunk
hypoplastic / absent A1 - so have a large reciprocal ACOM
Hypoplastic / absent ACOM
Bihemispheric ACA
A1 ACA is infraoptic (when it should run above the optic nerve!)
30
What is the middle cerebral artery?
It is the larger of the terminal branches of the internal carotid artery
Responsible for supplying the lateral part of the brain
Has 4 segments - horizontal, insular, opercular, cortical
31
What is the gross anatomy of the middle cerebral artery?
Origin: the larger of the terminal branches of the middle cerebral artery
4 segments
M1 - horizontal (M1, at the M1 segment, artery bifurcates or tri furcates)
M2 - insular
M3 - opercular
M4 - cortical
Termination is as numerous cortical arteries, largest is angular artery
32
What are the branches of the middle cerebral artery?
lenticulostriate arteries (medial and lateral)
which supply the lentiform nucleus and anterior capsule
Anterior temporal artery
33
What are the relations of the middle cerebral artery?
M1 - horiztontal part
runs immediately inferior to lentiform nucleus (which makes sense as it gives off the lenticulostriate arteries). is lateral to the optic chiasm
M2 - insular part
courses over the insula
M3 - opercular part
runs through the sylvian fissure
M4 - cortical part
34
What are the anatomical variations of the middle cerebral artery?
accessory MCA - which arises from the ACA
MCA duplication
early branching of MCA
MCA fenestration, lumen divides into 2 and then rejoins distally
35
What is the posterior cerebral artery?
It is part of the circle of willis and will terminate as the basilar artery.
36
What is the gross anatomy of the posterior cerebral artery?
Origin: it is the terminal bifurcation of the basilar artery
Has 4 segments
Pre communicating
Ambient
Quadrigeminal
Calcarine
Terminates as the calcarine artery which supplies the occpital cortex.
37
What does the posterior cerebral artery supply?
Thalamus and midbrain
Occipital cortex via the calcarine artery (calcarine sulcus)
choroid plexus
38
What are the branches of the posterior cerebral artery?
P1 - posterior communicating artery
- thalamostriate arteries / thalamoperforators
P2 - medial and lateral posterior choroidal arteries
P4 - calcarine artery
39
What are the relations of the posterior cerebral artery?
P1 PRE-COMMUNICATING - travels above the oculomotor nerve
P2 AMBIENT - PCA is wrapping around the midbrain
P3 QUADRIGEMINAL - PCA has the basal vein of rosenthal immediately medial
P4 CALCARINE - in the calcarine sulcus
40
What are the variations associated with the posterior cerebral artery?
Foetal PCOM
- PCOM is so large that the posterior cerebral artery comes from the ICA
Persistent carotid basilar anastomoses
- persistent primitive trigeminal artery, persistent proatlantial artery
Artery of pecheron (P1 / P2 artery which supplies the thalamus and the midbrain bilaterally)
41
What is the vertebral artery?
Part of the vertebrobasilar system - to provide blood circulation to the posterior circulation of the brain
42
What is the gross anatomy of the vertebral artery?
Origin: first branch of subclavian
Course: 4 parts
- extraosseous, foraminal, extraspinal, intracranial
- Extraosseous:
from first branch of subclavian to transverse foramen C6
- Foraminal:
Goes up from C6 - C1 transverse foramen
Extraspinal
C1 foramen behind lateral masses / atlanto occipital joint to foramen magnum dura
Intracranial
- from foramen magnum to confluence as basilar artery
Terminates as the basilar artery in the pre pontine cistern
43
What does the vertebral artery supply?
spinal cord. cerebellum.
44
What are the branches of the vertebral artery?
Anterior spinal artery
Posterior spinal artery
Posterior inferior cerebellar artery
45
What are the key relations to the parts of the vertebral artery?
Extraosseous - is posterior to the common carotid
Intraosseous - is within the foramen of C6 - C1. Anterior to the ventral rami of the spinal nerve
Extraspinal - is posterior to the lateral masses of the atlanto-occipital joint
Intracranial - is anterior to the medulla
46
What are the common anatomical variants associated with the vertebral artery?
Right vs Left dominance in size
Vertebral artery taking origin from the arch of aorta as opposed to the subclavian
Fenestration
Duplication
Persistent carotid basilar anastomosis
47
What makes up the basilar artery?
It is a confluence of the vertebral arteries
48
What is the origin, course and termination of the basilar artery?
Formed by the confluence of the vertebral arteries
Courses through the pre pontine cistern, ventral to pons
Divides into 2x posterior cerebral arteries in the interpeduncular/suprasellar cistern
49
What does the basilar artery supply?
Pons
Cerebellum
50
What are the branches of the basilar artery?
Posterior cerebral artery
Superior cerebellar artery
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery
Unnamed branches to pons
Labryinthine Artery
51
What are the relations of the branches of the basilar artery?
labrynthine artery runs in the internal acoustic meatus with CN7 + CN8
52
What are the anatomical variants associated with the basilar artery?
basilar artery fenestration
duplication
Persistent carotid - basilar anastomosis
Persistent primitive trigeminal/otic/proatlantal/ hypoglossal artery
53
What are cerebral ventricles?
CSF filled cavities within the brain
Contain the choroid plexus which produces CSF
54
What are the names of the cerebral ventricles?
Lateral ventricle
Third ventricle
Fourth ventricle
Cerebral aqueduct
55
What is the gross anatomy of the lateral ventricle?
Has a frontal horn, a body, occipital horn and temporal horn
Seperated from the other ventricle by the interventricular foramen of monroe
Dividing the two ventricles is the septum pellucidum and fornix
56
What is the gross anatomy of the third ventricle?
Slit like cavity, between the thalami
Drained by cerebral aqueduct
57
What is the gross anatomy of the fourth ventricle?
Diamond shaped cavity on the dorsal pons/ upper medulla
Roof is superior medullar velum / superior cerebral peduncle
Posterior is tectum
2 openings - median aperture of margendie
lateral aperture of luschka
58
What are the core foramina involving the ventricles?
Interventricular foramen of monroe
Lateral aperture of lushcka
Median aperture of magendie
59
What are the relations of the ventricles?
Lateral ventricle will be adjacent to caudate nucleus
Third ventricle - lateral will be the thalamus
Cerebral aqueduct - laterally is the periaqueductal grey matter (CN nuclei)
60
What is the arterial supply of the cerebral ventricles?
Choroid plexus - supplied by choroidal arteries - anteriorly coming from ICA, posterior coming from PCA
61
What is the venous drainage of the choroid plexus?
Choroidal veins. -> thalamostriate vein -> internal cerebral vein
62
What are the variations associated with the ventricles?
Cavum septum pellucidum
Cavum vergae
Cavum velum interpositum
63
64
65
66
Where is the frontal lobe?
Is the part of the brain anterior to the central sulcus
66
What is the function of the frontal lobe?
Responsible for speech
Intellect
Executive function
Personality
Inhibition
Broca's area!
67
What is the gross anatomy of the frontal lobe?
Pre central gyrus / primary motor cortex
Gyrus anterior to central sulcus
Premotor association cortex
Broca's area (lies in pars opercularis) - this is the most posteroinferior part of central sulcus
Pars triangularis points at Broca's area
68
What is the content of the frontal lobe?
Grey matter (of primary motor cortex)
White matter tracts
69
What are the relations of the frontal lobe?
Majority of the frontal lobe will sit in the anterior cranial fossa
Inferiorly - will be the orbital plate of the frontal bone
Inferolaterally - temporal lobe
Posteriorly - parietal lobe (after central sulcus)
70
What is the blood supply of the frontal lobe?
anterior cerebral artery - medial
middle cerebral artery - lateral
71
What is the venous drainage of the frontal lobe?
Superficial - frontal cortical veins, superficial middle cerebral vein
Deep - superior and inferior saggital sinuses
72
What is the nerve supply of the frontal lobe?
Crista galli
Optic chiasm and COW is inferior
73
What are the muscles / ligaments / fascia involved with the frontal lobe?
Falx cerebri - sits medially
Crista Galli
74
What are the anatomical variants associated with the frontal lobe?
Frontal person has changes in their personality. addiction / executive dysfunction
75
What is the parietal lobe?
It is the part of the brain which is posterior to the central sulcus.
but it is anterior to the occipitoparietal sulcus (on median surface of brain)
76
What is the function of the parietal lobe?
To integrate sensory information Contains the primary somatosensory cortex
Important role in vision - contains dorsal stream (ventral stream is in occipital lobe)
77
What is the gross anatomy of the parietal lobe?
Post central gyrus
Contains primary somatosensory cortex
Gyrus posterior to central sulcus
Parietal association area / cortex
Area posterior to postcentral gyrus
Dorsal stream of vision
- supramarginal gyrus / angular gyrus
78
What are the relations of the parietal lobe?
Anterior - frontal lobe (from the central sulcus)
Body of lateral ventricles in each lobe
79
what is the arterial supply of the parietal lobe?
Medial - anterior cerebral artery
Lateral - middle cerebral artery
80
What is the venous drainage of the parietal lobe?
superior and inferior saggital sinus
sphenoparietal sinus which drains to cavernous sinus
81
What nerves are contained in the parietal lobe?
Contains the dorsal stream of vision
82
What are the muscles / ligaments / fascia involved with the parietal lobe?
falx cerebri which is a medial struction
83
Clinical application of a parietal lobe infarct
Because it is sensory - an infarct will cause contralateral hemisensory loss
84
What is the temporal lobe?
It is a part of the brain which is resting in the middle cranial fossa
85
What is the temporal lobe responsible for?
Hearing - contains primary auditory cortex
contains wernicke's area - role in speech
contains the limbic system
86
What is the gross anatomy of the temporal lobe?
Superior temporal gyrus of heshcle
- primary auditory cortex
- contains wernicke's area
middle and inferior temporal gyri
- auditory association cortex
wernicke's area
- most posterior part of superior temporal gyrus, adjacent to sylvian fissure
Limbic system
- this is medial temporal lobe
- uncus, hippocampus and parahippocampal gyri
87
What are the relations associated with the temporal lobe?
Divided from the frontal and parietal lobes by the sylvian fissure
Overlies and hides in the insula cortex
Most medial temporal lobe in suprasellar cistern is 'uncus'
88
What is the arterial supply of the temporal lobe?
Superior - middle cerebral artery
inferior - posterior cerebral artery
89
What is the venous drainage of the temporal lobe?
Superficial - superficial middle cerebral vein, vein of labbe (inferior anastomotic vein)
Superior petrosal sinus, basal vein (of rosenthal)
90
What are the nerves involved with the temporal lobe?
auditory cortex
auditory association cortex
wernicke's area
limbic system
91
What is the occipital lobe?
Most posterior part of the brain
brain posterior to parietooccipital sulcus on medial surface of brain
92
What is the function of the occipital lobe?
involved in vision
Calcarine sulcus contained in the occipital lobe which has the primary visual cortex
Occipital association cortex
93
What is the course of the occipital lobe?
linked to lateral genucleate nucleus via optic radiation fibres
94
What are the relations of the occipital lobe?
Sits in posterior cranial fossa
Falx cerebri medially, tentorium cerebelli inferiorly
Calcarine artery runs medially through the calcarine sulcus
95
What is the arterial supply of the occipital lobe?
Posterior cerebral artery
- Calcarine artery
- usually from P3! the quadrigeminal segment
96
What is the venous drainage of the occipital lobe?
Vein of Labbe
Superior saggital sinus - confluence of sinuses
97
What is the nerves contained in the occipital lobe?
optic radiation fibres
98
What are the muscles / ligaments involved with the occipital lobe?
tentorium cerebelli is inferior, falx cerebri is midline
99
Clinical application of an infarct in the occipital lobe
An infarct of the calcarine artery from the posterior cerebral arterery will cause a homonymous hemianopia
100
What is the cerebellum?
Organ intimately related to the brainstem and posterior cranial fossa
Involved in coordination and fine tuning of movement
101
What is the gross anatomy of the cerebellum?
2 lobes - hemispheres
Midline vermis
Cerebellar peduncles
Superior - midbrain
Middle - pons
Inferior - medulla
Connect the cerebellum to the brainstem
Tonsils - inferior
102
What are the contents of the cerebellum?
Grey matter - superficially
White matter - centrally
103
What are the relations of the cerebellum?
Anterior: 4th ventricle
Superior + Inferior medullary velum: with superior and inferior cerebellar peduncles - makes the roof and floor of 4th ventricle
Tonsils are immediately superior to foramen magnum, key review area to check for herniation in suspected raised ICP
104
What is the arterial supply of the cerebellum?
superior cerebellar artery (from basilar artery)
anterior inferior cerebellar artery (from basilar artery)
posterior inferior cerebellar artery (from basilar artery)
105
What is the venous drainage of the cerebellum?
precentral cerebellar vein
superior vermian vein
- both will drain to the great vein valen
106
What are the muscles / ligaments involved with the cerebellum?
Superior tentorium cerebelli
107
What are the anatomical variants associated with the cerebellum?
cerebellar agenesis
chiari malformaiton
108
What is the pituitary fossa?
pituitary fossa is in the sphenoid bone - base in the body of sphenoid bone
Covered by dura (diaphragm sellae)
Laterally there is a cavernous sinus
109
Where does the pituitary fossa sit?
In the base of the sphenoid
110
What is the gross anatomy of the pituitary fossa?
Anterior
- tuberculum sellae
- anterior clinoid process
Posterior
- dorsum sellae
- posterior clinoid process
Superior
- diagphram sellae + infundibulum
- suprasellar cistern - optic chiasm, circle of willis
Inferior
- sphenoid sinus
Lateral
- cavernous sinus and its contents (CN3, CN4, V1, V2, CN6, ICA)
111
What are the contents of the pituitary fossa?
The pituitary gland
112
What is the arterial supply to the pituitary?
superior + inferior hypophyseal artery
(comes off the ICA)
113
What are the muscles/ligaments/fascia involved with the pituitary?
diagphram sellae
114
What are the anatomical variants associated with the pituitary fossa?
Empty sella syndrome - CSF + arachnoid protrude into the pituitary fossa, which leaves the pituitary gland shoved posteroinferiorly
115
What is the pituitary gland?
the pituitary gland is a protrusion of the hypothalamus at the bottom of the brain
Comes from the most inferior projection of the third ventricle - the tuber cinerum
**Link between endocrine + nervous systems**
116
What is the function of the pituitary gland?
Produces prolactin, ACTH, LH, FSH
117
What is the gross anatomy of the pituitary gland?
Two lobes
anterior pituitary (adenohypophysis)
- endocrine portion is 80 percent of gland
- uses superior hypophyseal artery
- uses portal circulation, venous channels connect two capillary beds
posterior pituitary (neurohypophysis)
- is a direct nerve extension of the hypothalamus
- stores vasopressin and oxytocin
- uses the inferior hypophyseal artery
Pars intermedia
- contains rathke cells
Infundibulum
- the stalk, which connects the pituitary to the hypothalamus (tuber cinereum)
118
What are the relations to the pituitary gland?
Sits in the pituitary fossa
Lateral - cavernous sinus and its contents
Superior - suprasellar cistern, optic chiasm and COW
119
What is the arterial supply of the pituitary gland?
superior hypophyseal artery (anterior)
inferior hypophyseal artery (posterior)
120
What is the venous drainage of the pituitary?
Portal venous drainage system
- venous channels connecting two capillary beds
- THis is why pituitary is bright on MRI
121
What is the nerve supply of the pituitary?
optic chiasm is directly above it
122
What are the muscles / ligaments / fascia surrounding the pituitary?
diaphgram sellae
123
What are cerebral venous sinuses?
Large intracranial venous channels
Covered in layers of dura mater
Predominantly drain to the internal jugular vein
124
Where do the cerebral venous sinuses sit?
Between the dural folds
125
What is the gross anatomy of the cerebral venous sinuses?
Superior saggital sinus - sits at the origin of the falx cerebri, drains to the confluence of sinuses
Inferior saggital sinus - runs in the free margin of the inferior part of the falx cerebri, superior to the corpus callosum, drains to the straight sinus
Straight sinus - runs from falcotentorial apex to confluence. recieves inferior saggital sinus and vein of galen, drains to confluence of sinuses
Confluence of sinuses - receives occipital, superior saggital sinus and straight sinus. empties into transverse sinus
occipital sinus - lies on inner surface of occiput
intercavernous sinus - links the cavernous sinus. Surrounds the pituitary
126
What are the possible anatomical variants associated with the unpaired venous sinuses?
Superior saggital sinus - can be off midline. drains to transverse sinus. absence, hypoplasia
Straight sinus - absent, hypoplasia, off midline, drains to transverse sinus instead of confluence, duplicated
SSS into one TS, SS into another SS
SSS and straight sinus fork and two forks become transverse sinuses
True confluence
127
What is the gross anatomy of the cavernous sinus?
Surrounds the pituitary
Core relations OTOM CAT
Oculomotor N
Trochlear N
Opthalmic division of trigeminal N (V1)
Maxillary division of trigeminal N (V2)
Abducens N
Internal carotid artery
drains to the sigmoid sinus via the superior petrosal sinus and inferior petrosal sinus
128
What is the gross anatomy of the sphenoparietal sinus?
Receives the superficial middle cerebral vein
Lies over the lesser wing of the sphenoid
Drains to cavernous sinus
129
What is the gross anatomy of the superior petrosal sinus?
Lies over the top of the petrous temporal bone
Drains to sigmoid sinus (unlike the inferior petrosal sinus)
130
What is the gross anatomy of the inferior petrosal sinus?
Lies over the top of the petrous temporal bone (more posteroinferior than the superior petrosal sinus)
drains directly to jugular foramen
131
What is the gross anatomy of the basilar venous plexus?
Lies over the clivus
Connects the cavernous sinus, superior petrosal sinus, inferior petrosal sinus
132
What is the gross anatomy of the transverse sinus?
Lies within the tenotrium cerebelli
origin is confluence of sinuses
Drains to the sigmoid sinuses
133
What is the gross anatomy of the sigmoid sinus?
Continuation of the transverse sinus
Receives the superior petrosal sinus
drains to jugular foramen
134
What is the supratentorial venous system?
Venous system which drains the brain.
All are valveless
Can be divided into superficial and deep
Deep veins are further divided into medullary and subependymal
135
What is the gross anatomy of the supratentorial venous system?
Superficial middle cerebral vein
-> lies in sylvian fissure, drains to sphenoparietal sinus
Superior anastomotic vein of trollard
-> lies over parietal lobe, links superficial middle cerebral vein to superior saggital sinus
Inferior anastomotic vein of Labbe
-> lies over temporal lobe, links superficial middle cerebral vein to transverse sinus
136
What are the deep supratentorial veins of the brain?
Medullary veins are nameless and variable
Drain to subependymal veins (large one which is internal cerebral + basal vein of rosenthal, these join to make the great vein of galen)
Internal cerebral vein - runs in roof of third ventricle. drains to great vein of galen (which joins basal vein of rosenthal)
Basal vein of rosenthal - runs in medial temporal lobe, runs into great vein of galen
great vein of galen - made with the confluence of the internal cerebral vein, and the basal vein of rosenthal, sits in quadrigeminal cistern, drains to straight sinus
137
What are the relations to the supratentorial veins of the brain?
Great vein of galen sits with the quadrigeminal cistern, so runs with PCA
Internal cerebral vein runs in the roof of the third ventricle
Basal vein of rosenthal runs in the medial temporal lobe - so it is adjacent to hippocampus
138
What are the anatomical variants associated with the supratentorial cerebral veins?
Great Vein of Galen Aneurysmal Malformations – get aneurysms of the vein of Galen. Worry about this in paediatric patients with cerebral vascular malformations!
139
What is the cavernous sinus?
It is one of the dural venous sinuses that surrounds the pituitary fossa
140
What is the gross anatomy of the cavernous sinus?
Anterior - tuberculum sella, anterior clinoid process
Posterior - dorsum sella, posterior clinoid process
Laterally - dural reflections, temporal lobe
Medially - is a midline structure surrounding the sella
141
What is contained in the cavernous sinus?
Oculomotor N
Trochlear N
Opthalmic division of trigeminal N (V1)
Maxillary vision of trigeminal N (V2)
Carotid Internal Carotid Artery - cavernous segment
Abducens N
Pituitary Gland
(OTOM CAP)
142
What is the course of the cavernous sinus?
Recieves blood from
inferior opthalmic vein
superficial middle cerebral vein
sphenoparietal sinus
Drains to the - superior petrosal sinus, inferior petrosal sinus, emissiary veins (go through the formane ovale and lacerum)
143
What are the muscles / ligaments for the cavernous sinus?
It is between the endosteal and visceral dura layers
144
What are the relations of the cavernous sinus?
Superior - optic chiasm, infundibulum, third ventricle
Inferior - sphenoid sinus, nasopharynx
Lateral - meckels cave which carries trigeminal ganglion (posterolateral)
Anterior - tuberculum sella
Posterior - dorsum sellae
145
What is the thalamus?
It is grey matter deep in the brain
lying in the walls of the third ventricle
146
What is the function of the thalamus?
Acts as a sensory switchboard, every sensory nuclei apart from the olfactory nucleus will have a thalamic nuclei which recieves sensory signals and sends them to the relevant associated cortex
147
What is the gross anatomy of the thalamus?
paired ovoid bodies of grey matter
Line the third ventricle
Has 2 growths, medial and lateral genuicleate nucleus
LATERAL - involved in vision and connects to the superior colliculus
MEDIAL - involved in hearing and connects to inferior colliculus
148
What are the key relations of the thalamus?
Anterior/ventral - subthalamic nuclei/genu of internal capsule
Posterior / dorsal - splenium of corpus callosum, cerebral aqueduct
Superior - lateral ventricle
Inferior - midbrain
Medial - third ventricle
Lateral - internal capsule, globus pallidus, putamen
Posterior cerebral artery in the ambient cistern is postero lateral
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What is the arterial supply of the thalamus?
Thalamoperforators from the posterior cerebral artery
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What are the variants associated with the thalamus?
Artery of percheron - a PCA variant. this is a single vessel which supplies both medial and lateral lobes of the thalami
60 percent of the thalami are joined across the third ventricle by an interthalamic adhesion
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What is the internal capsule?
Deep subcortical white matter projection fibres
Is continuous laterally with the corona radiata
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What is the function of the internal capsule?
Links the cortex to more caudal brain / spinal cord
Contains a high density of motor and sensory fibres
Posterior limb of internal capsule contains corticospinal tract, genu is corticobulbar
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Where does the internal capsule sit?
Medial to lentiform nucleus
Lateral to thalamus
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What is the gross anatomy of the internal capsule?
Anterior limb - recurrent artery of heubner, biggest perforating branch of the proximal ACA
Genu - genu of internal capsule = corticobulbar tract
Posterior limb - comes from ICA C7, posterior limb of the internal capsule is the corticospinal tract . Each part of the intenral capsule uses a different artery
Continuous laterally as the corona radiate (projection fibres)
Continuous inferiorly through the cerebral peduncles of midbrain
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What are the contents of the internal capsule?
Motor and sensory projection fibres - corticospinal tract is key (in posterior limb)
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What is the course of the internal capsule?
Links the cortex, through the midbrain (cerebral peduncles), to distal brain/spinal cord
Fibres fan out proximally as corona radiata
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What are the relations of the internal capsule?
Lateral - lentiform nucleus
Medial - thalamus / third ventricle
Superior - body of caudate nucleus
Inferior - fibres project to cerebral peduncles of midbrain
Posterior - occipital horn of laeral ventricle
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What is the arterial supply of the internal capsule?
ANTERIOR LIMB - recurrent artery of heubnar (ACA)
GENU - lateral lenticulostriate (M1 MCA)
POSTERIOR LIMB - anterior choroidal artery (ICA C7)
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What is the brainstem?
It is the communication between the cerebrum and the spinal cord
made of the midbrain, pons and medulla
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Function of brainstem?
Important for cardiovascular, respiratory function
Motor and sensation o face - 10 of 12 cranial nerve nuclei come from brainstem
Pathways necessary for sensation and motor to body:
-> spinothalamic, corticospinal tract, posterior column - medial leminiscal tract
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Where does the brainstem sit?
Posterior cranial fossa structure
Posterior is the cerebellum
Anterior is clivus of occiput
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What is the gross anatomy of the brain stem?
Midbrain - cerebral peduncles, tegmentum, tectum
Pons - ventral pons, dorsal tegmentum
medulla - ventral medulla (olive and pyramids), dorsal tegmentum
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What are the contents of the brainstem?
Cranial nerve nuclei
Spinothalamic tract
Corticospinal tract
medial leminisical posterior oclumn tract
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What are the relations of the brainstem>
Superiorly it is continuous with thalamus
Inferiorly it is continuous with spinal cord
medial - at level of midbrain - cerebral aqueduct
at level of pons - fourth ventricle
at level of medulla - central column
Anterior - basilar artery
posterior - cerebellum
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What is the arterial supply of the brainstem?
Vertebrobasilar system
midbrain - superior cerebellar artery
pons - pontine branches of basilar artery
medulla - branches from basilar a + vertebral a and also PICA and ASA
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What is the midbrain?
Origin of cranial nerves 3 and 4 (oculomotor N + trochlear N) and core structure is the cerebral peduncles
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What is the function of the midbrain?
Gives origin to oculomotor N + trochlear N
Has vital role in corticospinal/corticobulbar/corticopontine tracts vis a vis the cerebral peduncles
Roles in vision with the superior colliculus + inferior colliculus - hearing
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Where does the midbrain sit?
In the posterior cranial fossa
Inferior to thalamus but superior to pons
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What is the gross anatomy of the midbrain?
Butterfly - shaped
2 cerebral peduncles
Tegementum
Rectum
Cerebral peduncles - inferior projection of the fibres of the internal capsule
vital role in corticospinal / corticobulbar / corticopontine tracts
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Make sure to revisie poons medulla midbrain from notes!
