Y2: Neuroanatomy Flashcards
(342 cards)
1
Q
Osteology
Skull consists of 2 main regions
A
Neurocranium
Viscerocranium
2
Q
Osteology
Define Neurocranium
A
“protective case for brain”
3
Q
Osteology
Define Viscerocranium
A
jaw/facial skeleton
4
Q
Osteology
Neurocranium is formed by X bones. What are they?
A
8 Bones
Frontal
Parietal
Occipital
Ethmoid
Sphenoid
Temporal
5
Q
Osteology
The Neurocranium is divided into X zones
A
2 Zones
The Calvaria (skullcap)
The Cranial Base
6
Q
Osteology
Label the Neurocranium
A
7
Q
Osteology
Label the Viscerocranium
A
8
Q
Osteology
The Viscerocranium is made up of X bones, what are they?
A
14 bones
Includes the upper and lower jaw
Some: lacrimal, inferior concha, maxilla, mandible, nasal, zygomatic, palatine, Vomer,
9
Q
Osteology
The skull has sutures, what does this mean?
A
Joints vetween calvarial membrane bones of skull are known as sutures. Theses are important and needed for the infant’s brain growth and the flexibility of the sutures allows the baby’s head to pass through the birth canal.
10
Q
Osteology
What are the skull sutures?
A
Coronal, bregma, saggital, lambdoid, lambda, asterion, pterion
11
Q
Osteology
Sutures meet to form…..
A
Fontanelles
12
Q
Osteology/ Development
When do the Fontanelles close?
A
Closure of fontanelles
Posterior – 2-3 months
Sphenoidal – 6 months
Mastoid – 6- 18 months
Anterior – 18 months- 2 yrs
13
Q
Osteology
Label the Fontanelle
A
14
Q
Osteology
What is the internal cranial cavity divided into?
A
3 Fossa
Anterior
Middle
Posterior
15
Q
Osteology
Label the Internal Cranial Cavity
A
16
Q
Osteology
What are foramina?
A
Holes in the internal cranial cavity that allow structures such as nerves and blood vessles to pass through.
In the skull- this is mostly for cranial nerves.
17
Q
Osteology
Label the skull foramina
A
18
Q
Osteology
Label the skull foramina
A
19
Q
What is the cranial fossae?
A
Depression in the skull, relating to key structures of the brain
20
Q
What structures are related to the cranial fossae?
A
Anterior – Cerebrum (frontal lobe)
Middle - Cerebrum (temporal lobe)
Posterior – Cerebellum
Midline –
Hypophyseal/ pitutitary fossa
Brainstem
Foramen magnum- Medulla, Spinal cord
21
Q
Neuro- Nerves
Identify the Cranial Nerves:
A
22
Q
Neuro- nerves
What are each of the cranial nerves?
A
1- Olfactory
2- Optic
3- Oculomotor
4-Trochlear
5- Trigeminal
6- Abducens
7- Facial
8- Vestibulocochlear
9- Glossopharyngeal
10- Vagus
11- Accessory
12- Hypoglossal
23
Q
Which of the cranial nerves do not integrate with the brain stem
A
1 and 2
Olfactory
Optic
24
Q
What are the roles of the cranial nerves?
A
25
What are the layers of the Scalp?
S- Skin
C- Cranium
A- Aponeurosis
L- Loose Connx Tissue
P- Periosteum/ Pericranium
26
What is the meninges?
The meninges refers to the membranous structures that surround brain and spinal cord.
There are 3 layers: dura mater, arachnoid mater and pia mater.
Provide a supportive framework for the cerebral and cranial vasculature.
Acting with cerebrospinal fluid to protect the CNS from mechanical damage.
27
Label the meninges
28
What is the Dura Mater
two layered sheets of connective tissue:
Periosteal layer: lines surface of cranium
Meningeal layer: continuous with the dura mater and DEEP
29
dural venous sinuses are located
between the layers of the dura mater
They are responsible for the venous drainage of the cranium
**empty into the internal jugular veins.**
30
Dura Mater receives vascular supply from
**middle meningeal artery and vein.**
It is innervated by the trigeminal nerve (V1, V2 and V3).
31
What are dural reflections?
Folds of dura mater that protrude inwards upon itself.
32
What are the **X** dural reflections?
4 Dural Reflections:
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphagma sellae
33
What is the arachnoid mater?
middle layer of the meninges
lies under the dura mater
Avascular
No innervation
Connx tissue
34
What is the subarachnoid space?
Underneath the arachnoid
CSF
Small projections called arachnoid gradnulations allow CSF to re-enter the circulation
35
What is the pia mater?
Located under the subarachnoid space
Thin
Tightly adhered to brain and spinal cord surface
Follows the brain contours (gyri and fissures)
36
What is the spinal cord?
## Footnote
*LOB: Describe the anatomy of the spinal cord, its coverings, spinal nerves, and their parts.
Is the continuation of the Brainstem into the vertebral column through the Foramen Magnum
## Footnote
T2-weighted sagittal magnetic resonance imaging (MRI) of the cervical spine in the midline, showing the cervical and upper thoracic vertebrae (C. 2–T. 4).
37
Spinal cord is a continuation of the
## Footnote
*LOB: Describe the anatomy of the spinal cord, its coverings, spinal nerves, and their parts.
Continuation of medulla oblongata of the brain stem
38
Which cranial structure does the spinal cord run through
## Footnote
*LOB: Describe the anatomy of the spinal cord, its coverings, spinal nerves, and their parts.
The foramen magnum
39
The spinal cord terminates at
## Footnote
*LOB: Describe the anatomy of the spinal cord, its coverings, spinal nerves, and their parts.
L1
40
Cauda equina
## Footnote
*LOB: Describe the anatomy of the spinal cord, its coverings, spinal nerves, and their parts.
Nerve roots descend below conus medullaris (terminus of cord)
41
Spinal cord has 2 enlargements of ____ at ____ and ________
## Footnote
*LOB: Describe the anatomy of the spinal cord, its coverings, spinal nerves, and their parts.
Spinal cord has 2 enlargements of **grey matter** at **cervical** and **lumbar**
to provide sensory and motor to upper and low limb
42
Identify the spinal cord in axial view
## Footnote
*LOB: Identify the major landmarks of the spinal cord within the vertebral canal.
43
Identify grey matter
| Axial view of spinal cord
## Footnote
*LOB: Identify the major landmarks of the spinal cord within the vertebral canal.
Nerve cell bodies and their dendrites and synaptic contacts
Butterfly of H-shaped.
44
Describe and identify white matter
| Axial view of spinal cord
## Footnote
*LOB: Identify the major landmarks of the spinal cord within the vertebral canal.
Myelinated axons
Contains ascending and descending nerve fibres
Bundles arranged in columns (funiculi)
Each column consists of subdivisions called tracts
The tracts carry signals from one part of the CNS to another
45
Label the following:
## Footnote
*LOB: Identify the major landmarks of the spinal cord within the vertebral canal.
46
What are funiculi
| Axial view of spinal cord
## Footnote
*LOB: Identify the major landmarks of the spinal cord within the vertebral canal.
White matter
Bundles arranged in columns (funiculi)
Each column consists of subdivisions called tracts
47
The layers of Spinal Cord Meninges are...
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
Duramater
Arachnoid
Piamater
48
The dura mater extends from _ to __
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
Foramen magnum to S2
49
The arachnoid extends from _ to __
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
Foramen magnum to S2
50
The pia mater extends to __
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
the filum terminale till the coccyx
51
Define Filum terminale
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
thin filament which extends from the narrowed end of the spinal cord (conus medullaris) to the coccyx.
It is composed chiefly of the pia mater surrounding a continuation of the central canal, and some neural elements.
52
How does the meninges interact with roots?
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
The dura mater forms a separate sheath for each dorsal and ventral root.
Dura extends over the Dorsal root Ganglia posteriorly, and then becomes continuous with the epineurium of the nerve.
53
What is epineurium
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
The external connective tissue sheet which is continuous with the dura
54
What is epineurium
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
The external connective tissue sheet which is continuous with the dura
55
What is Ligamentum denticulatum
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
A thin ridge of pia mater on each side of the spinal cord
Extends from the foramen magnum to the L1 vertebra
Made up of 21 pointed projections of pia mater, extending laterally
Acts to keep the spinal cord movement limited within the duramater
## Footnote
"tooth ligament"
56
What are the ____ spaces related to the Spinal cord
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
Subarachnoid space: Contains cerebrospinal fluid
Dura-arachnoid interface: subdural (potential) space
Extradural (epidural space): Filled with semiliquid fat and venous plexus
57
Where does Lumbar Puncture/ Spinal Anaesthesia occur? and why?
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
subarachnoid space contains CSF
To avoid spinal cord- terminal end of the spinal cord
Lower border of L1 vertebra or L1-L2 intervertebral Disc.
58
Surface landmark for lumbar puncture
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
Surface landmark- Highest point of iliac crest (L4), Insert needle one or two spaces above this level.
59
What is Radiculopathy
## Footnote
*LOB: Describe the anatomical relationships of the meninges to the spinal cord and dorsal and ventral nerve roots, particularly in relation to root compression and the placement of epidural and spinal injections.
Radiculopathy is sensory or motor disturbance caused by pathology of a nerve root.
Such as:
* disc herniation
* presence of osteophytes
* spinal stenosis
* trauma.
## Footnote
T2-weighted sagittal MRI of the cervical spine,
showing intervertebral disc prolapse between C3/C4, C4/C5, and C5/C6 (Yellow arrows) and compression of the dural sac (Red arrows)
60
Identify the following:
* Posterior ramus
* Anterior / Ventral Root
* Posterior / Dorsal Root
* Spinal Nerve
* Anterior ramus
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
61
Anterior / Ventral Root
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Motor: Efferent neurons
Somatic – Muscles
Visceral – Organs (Autonomic nerves )
62
Posterior ramus
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Posterior ramus
Somatic motor to intrinsic back muscles
Somatic sensory to skin of back
63
Posterior / Dorsal Root
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Sensory: Afferent neurons
Somatic – Skin
Visceral – Organs (visceral peritoneum)
Cell bodies located in dorsal root ganglia
64
Spinal Nerve
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Contains motor and sensory fibers
Divides into anterior and posterior ramus
65
Anterior ramus
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Somatic motor to muscles of trunk and limbs
Somatic sensory to skin
66
The spinal cord gives rise to____ pairs of spinal nerves
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
8 Cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
67
Spinal nerves emerge from the________
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Spinal nerves emerge from the **intervertebral foramina **
68
Myotomes and Dermatomes
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
A skin area supplied by the sensory fibres of a single nerve root is known as a dermatome
A group of muscles primarily innervated by the motor fibres of a single nerve root is known as a myotome
69
Autonomic component
## Footnote
*LOB: Describe the anatomy of a typical spinal nerve, including its origin from dorsal and ventral spinal roots, its main motor and cutaneous branches and any autonomic component.
Afferent fibres synapse at the Lateral horn
**Connected to sympathetic ganglia via
White ramus communicans (Pre-ganglionic)
Grey ramus communicans (Post-ganglionic)
**
70
What is CSF
## Footnote
*LOB: Describe the ventricular system of CSF Flow and its parts, relations, and relevant clinical anatomy.
Ultrafiltrate of blood
* Produced by the choroid plexus
found in the walls of the
ventricles
* 150 ml
* 125 ml is intracranial
* The ventricles contain about 25
ml
* 100 ml is located in the cranial
subarachnoid space
* Secreted at a rate of 0.35–0.40
ml per minute
71
What is the function of CSF?
## Footnote
*LOB: Describe the ventricular system of CSF Flow and its parts, relations, and relevant clinical anatomy.
* Lubrication
* Shock absorber
* Transporter
* Nutrients
* Waste products
* Hormones
72
How does CSF circulate?
## Footnote
*LOB: Describe the ventricular system of CSF Flow and its parts, relations, and relevant clinical anatomy.
Lateral ventricles
Interventricular Foramen
Third Ventricle
Cerebral Aqueduct
Fourth Ventricle
Lateral Aperture, Medial Apeture, Lateral Apeture
Subarachnoid space
Arachnoid Villi
Sup Sagittal Sinus
73
What are the sub. arachnoid space and cisterns?
## Footnote
*LOB: Describe the ventricular system of CSF Flow and its parts, relations, and relevant clinical anatomy.
Spaces and pools of CSF for protection
1) Interpeduncular cistern (midbrain)
2) Pontine cistern (pons)
3) Cisterna Magna (medulla oblongata and cerebellum)
74
Define Tract
A collection of axons in the central
nervous system
75
Define Nerve
A collection of axons in the peripheral
nervous system
76
Define Nucleus
A collection of neuronal bodies in
the central nervous system
77
Define Ganglion
A collection of neuronal bodies in
the peripheral nervous system
78
What is the extent of the spinal cord?
Base of brain to lower border of L1 Vertebra
79
What are the segments of the spinal cord?
C1-8, T1-12, L1-5, S1-5, Co-1
80
What covers the spinal cord?
Inside the vertebral canal
* Enclosed in meninges- Dura, arachnoid and
Pia mater
* Surrounded by Extradural fat, lymphatics and
veins
* Cerebrospinal fluid located in Subarachnoid
space
81
Where are the tracts present?
In white matter
82
What is the ascending tract?
From the spinal cord to cerebral cortex
83
What is the descending tract?
From the cerebral cortex to the spinal cord
84
Features of the Ascending tract
Sensory in nature
* Arranged in the spinal cord
based on modalities they carry
* Orders of neurons- 1st, 2nd and
3rd
* Name gives a clue of
destination
85
What is the Spinothalamic Ascending tract?
Lateral- Pain and temperature
Anterior- crude touch and pressure
Posterior column- 2pt discrimination, vibration, position sense, sterognosis (depth perception), deep pressure
86
What is the lateral spinothalamic tract?
* **Receptors** - Free nerve endings
* **First order** - dorsal root ganglia
* **Second order**- Substantia gelatinosa
(Dorsal grey horn)
* **Third order** - Thalamus
* **Decussation/Intersects** - At the same spinal segment or one segment above
87
The spinothalamic tract in the cerebrum
* 2nd order neurons terminate in the ventral posterolateral (VPL) nucleus of the thalamus
* 3rd order neurons project to the primary somatosensory cortex via the posterior limb of the internal capsule
88
What is the anterior spinothalamic tract?
* **Modalities** - Crude touch, pressure
* **Receptors** - Free nerve endings
* **First order**- dorsal root ganglia
* **Second order** - substantia gelatinosa
* **Third order**- Thalamus
* **Decussation/intersects** - Some segments above
the spinal level of entry
89
What is special about substantia gelatinosa
If the tracts are mainly present in white matter, then this 3rd order neurone is present in the grey matter.
90
How can we clinically test for functioning lateral spinothalamic tracts?
Pain test
use steline neurological examination pin and temperature by volatile spray to create a cold sensation.
If present, spinothalamic working.
91
What is the posterior/dorsal column tracts?
is formed by two large fasciculi (bundles of nerve fibers) running through the posterior spinal cord: **fasciculus gracilis and fasciculus cuneatus.**
92
Features of the posterior column tract?
**Modalities** carried - Fine touch, vibration,
proprioception
* **Receptors** - Meissners/merkels/ tendon organs/muscle spindle (mechano and proprio receptors)
93
What are the roles of Gracile fasciculus and Cuneate fasciculus
**Gracile fasciculus**
* **below T6** ascend in the **medial** part of the dorsal column
**Cuneate fasciculus**
* **above T6** ascend in the **lateral** part of the dorsal column
## Footnote
Cuneate= wedge and Gracile=slim
94
The dorsal tract in the brainstem
* 1st order neurons pass through the dorsal column (gracile fasciculus and cuneate fasiculus), to reach the gracile
and cuneate nuclei in Medulla
* 2nd order neurons- Form internal arcuate fibres in medulla Cross over to the opposite side
* Ascend through brainstem as Medial lemniscus
* Medial lemniscus terminates on the
ventral posterolateral (VPL) nucleus of
the thalamus by synapsing to the 3rd
order neuron
* 3rd order neuron -> posterior limb of the internal capsule ->primary
somatosensory cortex
95
What is the medial lemniscus?
Ascending bundle of axons in the brainstem that cross specifically in the medulla oblongata
important for somatosensation from the skin and joints
lesion of the medial lemnisci causes an impairment of vibratory and touch-pressure sense.
## Footnote
Lemniscus means "ribbon"
96
How to clinically test the dorsal column
is concerned with fine, precisely-localised (or discriminative) touch, joint position sense, proprioception and vibration sense.
* It is tested using a high-amplitude, low-frequency (128Hz) tuning fork applied to bony prominences- Vibration
97
What are the roles of the pre and post central gyrus?
Pre-central gyrus- Motor
Post-central gyrus- Sensory
98
What is the descending tract?
***MOTOR**
* Cerebral cortex Spinal cord
* Lower motor neuron (LMN)
* Upper motor neuron (UMN)
99
What divides the descending pathways?
Pyramidal and Extrapyramidal
100
The pyramidal descending tract is
Corticospinal
Voluntary movement
of the contralateral (opposite) limbs/trunk
101
The extrapyramindal descending tract is...
* Vestibulospinal
* Reticulospinal
* Rubrospinal
* Tectospinal
102
What is the corticospinal tract?
* Longest continuous white matter pathway in the CNS
* Control of precision and speed of
skilled movements
* Forms visible ridges referred to as
the ‘pyramids’ on the anterior
surface of the medulla, so also called the Pyramidal Tract.
* Origin of upper motor neurones UMN in the cortex precentral gyrus
103
The corticospinal tract in the cerebrum
**origin**: motor and premotor areas of the frontal lobe
These fibres pass from cebral cotex to enter subcortical white matter
Via the Corona radiata
To the posterior limb of the internal capsule
## Footnote
Corona radiata= radiating crown
104
The corticospinal tract in the brainstem
descends through the anterior part of the brain stem
crus cerebri in midbrain
basilar pons
pyramids of the medulla- located on either side of the midline Crus cerebri
## Footnote
Crus cerebri = brain leg
105
Where does the corticospinal tract decussate?
## Footnote
decussate/ cross/ intersect
lowermost border of the medulla
90% of fibres cross in the caudal medulla at the decussation of the pyramids – Form Lateral corticospinal tract
* Remaining 10% fibres- Ventral corticospinal tract – Cross at the target spinal segment
106
The corticospinal tract in the spinal cord
Lateral corticospinal tract In the Lateral funiculus
Ventral corticospinal tract In anterior funiculus
Cross at the target spinal level
107
Considering the corticospinal tract, Lower motor neurones arise
Anterior horn cell in the Ventral grey horn of spinal cord at the respective level
108
How do lower and upper motor neurones interact?
109
What is the effect of a lower motor neuron lesion
* Paralysis/ paresis of specific muscles,
* loss or reduction of tendon reflex activity
* reduced muscle tone,
* fasciculations (small contraction)
* muscle atrophy
110
What is the effect of upper motor neurone lesions?
* Paralysis/ paresis of movements
* increased tendon reflex activity
* increased muscle tone
* spasticity
111
Describe the Dura Mater
Tough fibroud outermost covering
2 layers:
Endosteal layer- periosteum over skull bones
Meningeal layer- continuous with the dura mater of the cord
112
Describe the Arachnoid Mater
Consists of arachnoid membrane and the arachnoid trabeculae
113
Describe the Pia Mater
Blood vessels run along the surface of the pia wihtin the subarachnoid space.
114
What are the two layers of the dura mater?
Endosteal- periosteum over skull bones
Meningeal- continuous with the dura mater of the spinal cord. (dura proper)
115
What are the features of the cranial dura mater
| (meningeal layer)
Sends inwards four septa
Divides the cranial cavity into freely communicating spaces
Subdivisions of the brain
116
What is a role of the dura mater?
Restrict rotatory displacement of the brain
117
What are the reflections of the dura mater?
Falx cerebri- midline
Diaphragma sellae- passage of infundibulum
Tentorium cereblli- roofs over posterior cranial fossa- suports the occipital lobes
Tentorial notch- passage of mid brain
Falx cereblli- projects forward between cerebellar hemispheres
118
What is the falx cerebri
A reflection of dura mater
lies in the midline
between two cerebral hemispheres
119
What is the diaphragma sellae?
A reflection of dura mater
small circular fold
allows passage of the infudibulum
120
What is the falx cerebelli
A reflection of dura mater than projects forward between cerebllar hemispheres
121
What is the tentorial notch?
a reflection of dura mater
passage of the midbrain
122
What is the tentorium cerebelli
reflection of the dura mater which roofs over the posterior cranial fossa
covers the upper surface of the cerebellum
supports the occipital lobes of the cerebral hemispheres
123
What sinuses does the falx cerebri contain?
Superior Sagittal, Inferior sagittal and Straight Sinus
124
What are the ends and margins of the falx cerebri?
ENDS: anterior and posterior
MARGINS: superior and inferior
125
What are the margins and ends of the tentorium cerebelli?
Attatched margin and free margin
Pulled up by attachment ot falx cerebri
126
What are the features of the falx cerebelli
Small fold along internal occipital crest
Contains occipital sinus
127
What are the structural features of the diaphragma sellae
Circular fold over the hypophyseal fossa
Pierced by infundibular stalk of pituitary
Contains intercavernous sinus
128
When dura stretches...
feel headache
129
How to name the arachnoid spaces?
subdural space above
----a-r-a-c-h-n-o-i-d----
subarachnoid space
130
What are the features of the arachnoid mater?
Thin avascular layer between pia and dura
Loosely applied layer with projections
All structures passing to / from brain pass through subarachnoid space
131
How does CSF interact with the meninges?
Subarachnoid space contains cerebrospinal fluid (CSF)
Produced by choroid plexus in brain ventricles
Runs through the ventricular system
Leaves the ventricular system from the fourth ventricle to enter the subarachnoid space.
Gets absorbed back into the dural venous sinuses through arachnoid granulations
132
What are arachnoid granulations?
Projections of the arachnoid that affects the transfer of csf to venous sinuses
at the superior sagittal sinus, the arachnoid pierces the dura as a number of finger-like or cauliflower-shaped projections.
However if no cauliflower head then arachnoid villi
133
What are the role of arahnoid villi?
at top, perforations through which the subarachnoid space communicates with the venous sinus.
134
What is the Pia mater?
Very delicate vascular membrane (nourish)
Closely invests brain following gyri / sulci
135
What is the function of the pia mater?
Function: Vascular membrane for nourishment. Cerebral arteries enter brain carrying sheath of pia mater with them
136
How does the meninges cover the spinal cord?
137
Extradural Vs. Subdural Haematoma
Extradural Haematoma- Almost always arterial, Emergency surgical management- Burr holes or craniotomy to release the pressure on the brain
Subdural Haematoma- Almost always venous, mostly subcortical bridging veins, Treatment depends on size, severity and acute nature.
138
What are the venous sinuses
situated between periosteal and meningeal layers of dura
Receive tributaries (river, vessel) from the brain, skull bones, the orbit and the internal ear
139
What are the features of the veins of the brain
Very thin walls and they possess no valves.
Emerge from the brain and lie in the subarachnoid space.
Pierce the arachnoid mater and the meningeal layer of the dura and drain into the cranial venous sinuses.
140
What is the superior cerebral vein?
External cerebral vein
veins- pass upward over the lateral surface of the cerebral hemisphere and empty into the superior sagittal sinus
141
What is the superficial middle cerebral vein?
Superficial middle cerebral vein drains the lateral surface of the cerebral hemisphere. It runs inferiorly in the lateral sulcus and empties into the cavernous sinus
142
What is the deep middle cerebral vein?
drains the insula and is joined by the anterior cerebral and striate veins to form the basal vein.
143
What is the great cerebral vein?
basal vein joins the great cerebral vein, which in turn drains into the straight sinus
144
Label the dural venous sinuses
145
Lable the dural venous sinuses
146
What is the cavernous sinus
Important sinus in the middle cranial fossa
Related to important structures – Internal carotid artery, Cranial nerves -3,4, 5 (1st and 2nd divisions), 6
147
Where is the primary auditory area?
Located on superior temporal gyrus
Reception and interpretation of sound
148
What area is responsible for motor speech?
(Broca’s) area
Located just above lateral sulcus, usually on the left side of the brain
Controls movements involved in speech
149
What area is responsible for comprehension of speech?
**Wernicke's area**
Located in the posterior section of the superior temporal gyrus on the left side of the brain
Comprehension of speech
150
What is the primary visual area?
Primary visual area
Located on the posterior pole of the occipital lobe around the calcarine sulcus
Receives visual impressions
| Calcarine sulcus in blue
151
What are brodmann's cortical areas?
Important areas
Primary Motor area- 4
Primary Sensory areas- 3,2,1
Primary visual area- 17
Visual association areas- 18,19
Motor speech (Broca’s) area- 44
Sensory speech (Wernicke’s) area- 22
Primary auditory area - 41
152
Brain lesions
## Footnote
CLINICAL ANATOMY
Focal lesions of the precentral gyrus- contralateral hemiparesis
Lesions of postcentral gyrus - contralateral hemisensory loss.
Widespread degeneration of the cerebral cortex gives rise to symptoms of dementia.
153
How is the frontal lobe divided?
Superior frontal gyrus
Middle frontal gyrus
Inferior frontal gyrus
154
How is the temporal lobe divided?
Superior temporal gyrus
Middle temporal gyrus
Inferior temporal gyrus
155
How is the medial surface of the cerebrum divided?
Paracentral lobule
Cingulate gyrus and sulcus
Parieto-occipital sulcus
Calcarine sulcus
156
How is the inferior surface of the cerebrum divided?
Orbital Sulcus and gyri
Collateral sulcus
Occipitotemporal sulcus
Uncus
Parahippocampal gyrus
157
Brain is supplied arterially by
Two internal carotid arteries
Two vertebral arteries
158
Two internal carotid arteries
Two vertebral arteries anastamose to form
The circle of willis
159
Internal Carotid Arteries
enter through the carotid canal
terminate at Anterior cerebral artery and Middle cerebral artery
160
How does the internal carotid artery run?
Runs anteriorly forwards within the Cavernous sinus
161
The vertebral arteries...
Ascend in the neck through the foramina in the transverse processes of the upper six cervical vertebrae
Enters cranial cavity through **foramen magnum**
162
The vertebral arteries join to form
the basilar artery
On the ventral surface of pons
163
The circle of willis
product of the 4 arteries anastamosing. Not complete in majority of people
164
The circle of willis is formed by:
Anterior communicating
Anterior cerebral
Middle cerebral
Internal carotid
Posterior communicating
Posterior cerebral
Basilar
165
What is the function of the circle of willis?
Allows for collateral circulation of blood if one or part of the circle becomes blocked or narrowed
Avoids ischemia
166
What area of the brain does the anterior cerebral supply?
167
What area of the brain does the middle cerebral supply?
168
What area of the brain does the posterior cerebral supply?
169
Middle Cerebral artery supplies...
a large part of the lateral surface
| Lies in the lateral sulcus
170
# 1.
Anterior Cerebral artery supplies....
supplies a large part of medial surface
| lies Close to corpus callosum,
171
Midbrain is supplied by
posterior cerebral, superior cerebellar, and basilar arteries.
172
Pons is supplied by
basilar, Pontine arteries, anterior inferior, and superior cerebellar arteries.
173
Medulla oblongata is supplied by
Basilar, vertebral, anterior and posterior spinal, posterior inferior cerebellar.
174
The cerebellum is supplied by
superior cerebellar, anterior inferior cerebellar, and posterior inferior cerebellar arteries.
175
Label the basilar artery
176
The spinal cord is supplied by...
2 posterior spinal arteries
1 anterior spinal artery
reinforced by small segmental arteries arsing from arteries outside the vertebral column
anastomose on the surface of the cord and send branches into the substance of the white and gray matter.
177
Blood loss at the anterior cerebral causes
loss of primary motor cortex for lower limb and perineum of contralateral side
incontinence
178
Blood loss/ blockage at the middle cerebral leads to
loss of sensatioin and motor function (excludes lower limb and perineum)
Loss of Broca and Wernickes
179
Loss of blood/ blockage at posterior cerebral....
leads to damage of primary visual cortex and visual field defects
Loss of hippocampus and memory loss
180
The bony orbit is a ____ structure
pyyramidal
181
The Bony Orbit is made of ____ bones, name them.
**7**
1. Sphenoid.
2. Frontal.
3. Zygomatic.
4. Ethmoid.
5. Lacrimal.
6. Maxilla.
7. Palatine.
182
What are the two axis?
Visual axis- line of sight
Anatomical axis- an imaginary plane passing
through the centre of the orbital pyramid,
dividing it into symmetrical left and
right halves.
183
Where do the anatomical and visual axes coincide?
Eye abducted 23 degrees
184
Where is the anatomical axis of the orbit?
22.5 degrees from the midline
185
External anatomy of the eye
Sclera
Limbus
Iris
Cornea
186
The eye has 3 coats, they are....
Fibrous: sclera and cornea
Vasculae: choroid, cilliary body and iris
Neural: retina
187
What is the fibrous tunic?
The sclera and cornea are tough and collagen-rich tissue
continour with the dural sheeth
188
What is the vascular tunic?
Vascular tunic - Choroid, ciliary body and iris.
Clinically known as the “uveal tract”.
189
What is choroid?
pigmented – melanin –
absorbs light and limits reflection
supplies the outer retina with nutrients, and maintains the temperature and volume of the eye.
190
What is the Nerual layer?
Retina
Macula lutea and fovea centralia
Optic disk (blind spot)
Central retina artery and vein (branch in quadrants)
191
What is the macula ?
The portion of eye at
the center of the retina that
processes sharp, clear vision
192
What is the fovea?
depression at the centre
of the macula that provides
greatest visual acuity
193
What is the refractory media of the eye?
Zonule fibres- suspensory ligament
attatched to ciliary muscle (ring)
194
How is far vision produced?
Flat lens
Suspensory ligament taught
Ciliary muscle relaxed. (parasympathetic ganglion)
195
How is near vision produced?
thick lens
suspensory ligament relaxed
ciliary muscles contract
196
The eye is divided into 2 segments
anterior- lens
posterior- inner eye
197
Where is the lens situated?
Hyaloid fossa of the vitreous body.
198
What is aqueous humour?
Clear watery fluid fills the anterior chamber maintaining shape, nutrients and intraocular pressure.
Produced by the ciliary body of the posterior chamber and flows to the anterioir chamber via the canal of schlemm
199
What are the 7 extraocular muscles?
Recti- Lateral, Medial, Superior, Inferior
Obliques- Superior, Inferior
Levator palpebrae superioris
200
What is the nerve supply of the extraocular muscles?
## Footnote
LR6 SO4 – Lateral rectus 6 superior rectus 4
201
What is the origin of the rectus muscles?
attached to
common tendinous ring of zinn
(surrounds optic nerve)
202
What is the insertion of the rectus muscles?
sclera of the eyeball behind limbus
203
What is the origin and insertion of the inferioir oblique muscle?
**O** - The anterior aspect of the orbital floor (maxilla mainly)
**I** - Sclera of the eye, posterior to the lateral rectus
204
What is the origin and insertion of the superior oblique muscle
O – Body of the sphenoid bone
* I – sclera of the eye, posterior to
the superior rectus.
205
Actions of the extraocular muscles
206
How is intoirsion of the eye achieved?
207
How is extosion of the eye achieved?
208
What is the pathway of light?
Pathway
* Optic nerve
* LGB
* Pre-tectal nucleus in Mibrain
* RELAY BILATERALLY
* Edinger Westphal nucleus –
Midbrain
* CN III
* Parasympathetic supply- Cilary
muscles
* Constriction of pupil
209
What is the Accommodation reflex?
This reflex allows us to focus on
objects as they are brought close to
the face. They rely on the 3Cs.
1. Constriction of the pupil
(oculomotor nerve)
2. Convergence of the eye (medial
rectus contraction-oculomotor
nerve)
3. Contraction (ciliary body
contracts making the lens thicker)
210
Where is the cerebellum situated?
Posterior cranial fossa
below tentorium cerebelli (dural reflection)
Hindbrain
Posterior to fourth ventricle, pons, medulla oblongata
211
What is the function of the cerebelllum
posture
voluntary movements
smooth contraction of voluntary muscles,
coordination of actions
212
Cerebellum structure.
Highly convoluted folds, called ‘Folia’
Ovoid shape
Two cerebllar hemispheres
Cetnral narrow Vermis
213
Fissures of the cerebellum
Primary fissure: wide V-shaped fissure separating
anterior and posterior lobes
* Posterolateral fissure: separates posterior and
flocculonodular lobes
* Horizontal fissure: A deep fissure found along the margin
of the cerebellum separates the superior from the inferior
surfaces (no morphologic or functional significance)
214
Lobes of the cerebellum
* Anterior lobe
* Posterior lobe
* Flocculonodular lobe
215
White matter in the cerebellum is shaped
like a tree
abor vitae
tree of life
216
Deep nuclei of the cerebellum
Dentate
- Globose
- Emboliform
- Fastigial
217
The cerebellar peduncles.
t is connected to the posterior aspect
of the brainstem by three symmetrical
bundles of nerve fibers
* Superior cerebellar peduncles
* Middle cerebellar peduncles
* Inferior cerebellar peduncles
Describe the major gross anatomical features of the
cerebellum.
218
Superior cerebellar peduncle-
Mainly efferent **fibers to thalamus and red nucleus.**
* Afferent fibres- Ventral spinothalamic tract.
* General functions are to **convey sensation and
proprioception.**
219
Middle cerebellar peduncle-
Largest among the three cerebellar peduncles.
* Conveys motor information from the cerebral cortex and
pons to the cerebellum via the afferent
corticopontocerebellar pathway.
220
Inferior cerebellar peduncle
Carries both efferent and afferent fibers mainly concerned
with integrating proprioceptive sensory information with
motor functions such as balance.
* Integrates proprioceptive sensory information and postural
maintenance via the dorsal spinocerebellar tract (Mossy
fibres).
221
What are the zones of the cerebellum
Vermis - In the midline of the
cerebellum is the.
* Intermediate zone- Either side of
the vermis
* Lateral hemispheres- Lateral to
the intermediate zone
222
Cerebrocerebellum (lateral zone) is responsible for
Involved in planning movements and motor learning.
* It receives inputs from the cerebral cortex and pontine nuclei
* Sends outputs to the thalamus and red nucleus.
* This area also regulates coordination of muscle activation
223
Spinocerebellum (vermis and intermediate) is responsible for
Involved in regulating body movements by allowing for
error correction.
* It also receives proprioceptive information.
224
Vestibulocerebellum (flocconodular lobe) is responsible for
Involved in controlling **balance** and **ocular reflexes**
* It receives inputs from the vestibular system and sends outputs
back to the vestibular nucleus.
225
Signs of cerebellar disease
Hypotonia
* Alteration of Gait - The patient assumes a wide base when he or she
stands and is often stiff legged. Gait is lurching and staggering towards
the affected side.
* Ataxia- Disturbance of voluntary movements, intentional tremor, past-
pointing on finger-nose test
* Dysdiadochokinesia- Inability to perform rapid alternating movements
* Dysarthria- difficulty in speech
* Nystagmus
226
What is the brainstem?
Stalklike structure within the posterioir cranial fossa of the skull.
It connects the forebrain and spinal cord
Contains: Midbrain, pons and medulla oblongata
227
What are the main functions of the brainstem?
Conduit for tracts through the CNS
Houses cranial nerve nuclei III to XII
Locaiton of reflex centres
Respiration, CVS funcitons, Conciousness
228
Label the brainstem:
229
Identify the following surface features
230
What is the Superior colliculi?
Visual pathway
231
What is the inferior colliculi?
Auditory pathway
232
What is the superior medullary velum?
a thin, transparent lamina of white matter, which stretches between the superior cerebellar peduncles
233
What is the inferioir medullary velum?
thin layer of white substance, prolonged from the white center of the cerebellum, above and on either side of the nodule;
234
Identify the surface features
## Footnote
Anterior view
235
What are the cerebral peduncles?
The cerebral peduncles are the two stalks that attach the cerebrum to the brainstem.[1] They are structures at the front of the midbrain which arise from the ventral pons and contain the large ascending (sensory) and descending (motor) nerve tracts that run to and from the cerebrum from the pons.
**Cranial nerve 3 (oculomotor nerve) appears ventrally between the two cerebral peduncles in the interpeduncular fossa. Cranial nerve 4 (trochlear nerve) wraps around the lowest part of the cerebral peduncle.[8]**
236
What is the basilar groove?
237
What is the ponto-medullary junction?
238
What is the olive?
INF: involved in cerebellar motor-learning and function
SUP: part of the auditory system, aiding the perception of sound.
239
What is the pyramid?
contain motor fibers of the corticospinal and corticobulbar tracts
240
Identify the following surface features
## Footnote
posterior view
241
What is the corpora quadrigemina?
reflex centers involving vision and hearing.
Remember 2 eyes and 2 ears = 4 (quad)
242
What is the superior colliculus?
a paired structure in the rostral midbrain that is involved in incorporating environmental stimuli and coordinating gaze shifts involving both eye and head movements.
243
What is the inferior colliculus?
It acts as the channel for almost all auditory signals in the human body. Its primary roles are signal integration, frequency recognition, and pitch discrimination.
244
What is the superior, middle and inferior cerebellar peduncle?
Inferior: Balance, conjugate eye movement
Superior and inferioir: posture, coordination, motor correction
Superior and middle: planning and initiate movement, coordination, motor learning, correction of coluntary movements.
245
What is the cuneate tubercle?
enlargement at the end of the cuneate fasciculus that is produced by cuneate nucleus.
246
What is the gracile tubercle?
part of the dorsal column medial leminiscal sensory neuronal pathway.
247
What is the median sulcus of the brainste,?
248
What is the facial colliculus
a unique feature located in the pons that houses the abducens nucleus and the facial motor fibers.
249
What is the striae medullares
"a part of the epithalamus and forms a bilateral white matter tract of the initial segment of the dorsal diencephalic conduction system (DDCS)."
allowing the forebrain to influence midbrain monoaminergic output.
250
Identify the cranial nerves
251
Identify the cranial nerves in the anterior view
252
What are the functions of the cranial nerves?
253
# Cranial nerves
The following mnemonic means...
**Some Say Money Matters, But My Brother Says Big Brains Matter Most (1-12)
**
S- sensory M-motor B-both
Sensory: 1, 2, 8
Motor: 3, 4, 6, 11,12
Both: 5,7,9,10
254
What important events occur in the medulla?
Decussation of motor fibres of cortico-spinal tract
Decussation of sensory fibres of the posterior column tracts
255
What vessels supply the medulla?
Branches of the vertebral artery:
Anterior spinal artery
Posterior spinal arteries
Posterior inferior cerebellar arteries
Direct medullary branches
256
Label the vessels of the medulla
257
What is lateral medullary syndrome of wallenberg
**blockage of inf cerebellar artery**
Vestibular symptoms
Ipsilateral cerebellar signs
Ipsilateral loss of pain, temperature- face
Contralateral loss of pain, temperature- trunk, limbs
Ipsilateral laryngeal, pharyngeal, palatal hemiparalysis
Ipsilateral Horner’s syndrome
258
What is medial medullary syndrome?
**Anterior spinal Artery blocked**
Ipsilateral hypoglossal palsy
Contralateral loss of proprioception, discriminative touch, vibration
Contralateral hemiplegia
259
How is the pons seperated?
Lower Pons (through CN VII)
Upper Pons (through CN V)
260
What features are visible in the lower pons
Nucleus of abducent nerve
Motoro nucleus of facial nerve
Facial nerve
Abducent nerve
261
What features are visible in the upper pons?
Motor nucleus of the trigeminal nerve
Main sensory nucleus of trigeminal nerve
Sensory root of trigeminal nerve
Motor root of trigeminal nerve
262
What are the arterial supply of the pons?
Pontine branches of basilar artery
Anterior inferior cerebellar artery (AICA)
Superior cerebellar artery
263
What is Millard Gubler syndrome?
**occulsion of branches of basillar artery**
Ipsilateral medial squint
Ipsilateral facial palsy
Contralateral hemiplegia
264
What is pontocerebellar syndrome?
**·Caused by pressure from acoustic neuroma**
Tinnitus, deafness & vertigo
Ipsilateral ataxia
Ipsilateral lower motor neuron type of facial palsy
Contralateral loss of pain & temperature sensation of the face
loss of corneal reflex
265
What are the surface features/parts of the midbrain?
Tectum (colliculi)
Tegmentum
Substantia Nigra
Crus cerebri
Cerebral peduncles
Aqueduct
266
The midbrain can be divided by....
The level of the inferior colliculus
The level of the superior colliculus
267
What features are present in the Inferior colliculus level of the midbrain?
Trochlear nerve
Inferior colliculus
Substantia nigra
268
What features are present in the superior colliculus level of the midbrain?
superior colliculus
red nucelus
susbtantia nigra
oculomotor nerve
269
What is the blood supplu of the midbrain?
Posterior cerebral artery
Superior cerebellar artery
Posterior communicating A
Anterior choroidal artery
270
What is congential hydrocephalus?
**blockage of cerebral aqueduct**
271
What is Weber's syndrome?
**posterior cerebral artery occulusion**
Damage to oculomotor nerve and crus cerebri
Ipsilateral Ophthalmoplegia
Contralateral Hemiplegia
272
What is the basal ganglia?
## Footnote
Describe the main parts of the basal ganglia and understand their functional connections.
A number of sub-cortical nuclear mases in the inferior cerebral hemisphere, lateral to the thalamus.
273
What are the main parts of the basal ganglia?
## Footnote
Describe the main parts of the basal ganglia and understand their functional connections.
1) caudate nucleus
2) putamen
3) globus pallidus
4) substantia nigra
5) subthalamic nuclei
6) Claustrum
***7) Technically the amygdala*** by location but limbic by function
274
What is the corpus striatum for?
## Footnote
Describe the shape of the corpus striatum and how it relates to the cavity of the lateral ventricle and to the internal capsule.
* motor and reward systems;
* receives glutamatergic and dopaminergic inputs from different sources
* the primary input to the rest of the basal ganglia
275
What is the structure of the corpus striatum?
## Footnote
Describe the shape of the corpus striatum and how it relates to the cavity of the lateral ventricle and to the internal capsule.
**Dorsal division contains:**
* Caudate nucleus
* Lentiform Nucleus (Putamen and Globus pallidum)
**Ventral division contains:**
* Nucleus accumbens
* Olfactory tubercle
276
What is the lentiform nucleus?
## Footnote
Describe the shape of the corpus striatum and how it relates to the cavity of the lateral ventricle and to the internal capsule.
The area of the corpus striatum containing the putamen and the globus pallidum
277
What is the caudate nucleus?
## Footnote
Describe the main parts of the basal ganglia and understand their functional connections.
Parts- Head,Body, Tail
a paired, “C”-shaped subcortical structure which lies deep inside the brain near the thalamus.
278
What is the SUBSTANTIA NIGRA
## Footnote
Describe the main parts of the basal ganglia and understand their functional connections.
* Collection of neurons in the midbrain immediately behind the crus cerebri
* Pars Compacta- Sends Efferents to the Striatum
* Pars Reticulata- Recieves Afferents From Corpus Striatum and subthalamic nucleus
## Footnote
Clinical relevance: loss of this = loss of dopamine = parkinsons
279
What is the SUBTHALAMIC NUCLEUS
## Footnote
Describe the main parts of the basal ganglia and understand their functional connections.
* Shaped like a biconvex lens In the subthalamic region
* Junction of internal capsule and crus cerebri
* Responsible for integrating and smoothening movements
280
Label the structures of the basal ganglia
281
What structures do the corpus striatum interact with?
## Footnote
Describe the shape of the corpus striatum and how it relates to the
cavity of the lateral ventricle and to the internal capsule.
* Corpus Callosum lies above the head and body
* Thalamus lies medial to most of the body of caudate nucleus
* Between thalamus and caudate nucleus:
– Stria Terminalis
– Thalamostriate Vein
Separated from
Lentiform nucleus by Internal Capsule (Anterior Limb)
282
Label the following
## Footnote
Describe the main parts of basal ganglia ondifferent brain sections as used clinically using CT and MRI scans.
283
Label the following
## Footnote
Describe the main parts of basal ganglia ondifferent brain sections as used clinically using CT and MRI scans.
284
Label the following
## Footnote
Describe the main parts of basal ganglia ondifferent brain sections as used clinically using CT and MRI scans.
285
What is the function of the basal ganglia?
## Footnote
Describe the functions of the basal ganglia to cognition, emotion and behavior.
feedback mechanism to the cerebral cortex, modulating and refining cortical activation.
motor refinement, preventing unwanted movements, reducing the excitatory input to the
cerebral cortex. Thus prevents excessive and exaggerated movements.
in modulating cognitive and emotional responses through the Ventral striatum which
receives limbic inputs
control of motor activity by influencing the cerebral cortex of the same side (which influences the opposite
side of the body):
286
What are the BASAL GANGLIA CIRCUITS
## Footnote
Describe the functions of the basal ganglia to cognition, emotion and behavior.
* Motor Loop: Learned Movements (writing, passing a ball)
* Cognitive Loop: Motor Intentions (preparing for movements)
* Limbic Loop: Emotional Aspects of movement
* Oculomotor Loop: Voluntary Saccades (using the eye muscles to look at an object)
287
What are the BASAL GANGLIA **direct** motor loop?
## Footnote
Describe the functions of the basal ganglia to cognition, emotion and behavior.
288
What os the BASAL GANGLIA **indirect** motor loops?
## Footnote
Describe the functions of the basal ganglia to cognition, emotion and behavior.
289
What is the role of dopamine in the basal ganglia motor loop?
## Footnote
Describe the functions of the basal ganglia to cognition, emotion and behavior.
Dopamine **stimulates** direct pathway
**inhibits** indirect pathway and so increases motor activity
290
What is the limbic loops?
## Footnote
Describe the functions of the basal ganglia to cognition, emotion and behavior.
* Involved in giving motor expression to emotions (through smiling, gestering etc)
* The loop is rich in dopaminergic nerve endings
* Their decline may account for mask-like facies in Parkinson’s disease
291
# Clinical Anatomy
What is dyskenesia
## Footnote
Describe the functions of the basal ganglia to
cognition, emotion and behavior.
Hyperkinesia - tremors, athetosis, chorea, ballism
Hypokinesia– Parkinson’s disease
▪ Disturbance of muscle tone (rigidity)
292
# Clinical Anatomy
What is tremor?
## Footnote
Describe the functions of the basal ganglia to
cognition, emotion and behavior.
Is a rhythmical, alternating abnormal involuntary activity having a
relatively regular frequency and amplitude
293
# Clinical Anatomy
What is Athetosis?
## Footnote
Describe the functions of the basal ganglia to
cognition, emotion and behavior.
Is characterised by movements that are involuntary,
slow and writhing involving particularly the distal
muscles of the extremities
294
# Clinical Anatomy
What is Chorea?
## Footnote
Describe the functions of the basal ganglia to
cognition, emotion and behavior.
Quick, jerky, irregular involuntary movements that are non repetitive
**Sydenham’s chorea
**❖ disease of childhood
❖ associated with rheumatic heart
**Huntington’s chorea
**autosomal dominant
* Dopa secreting neurones of SN
overactivated
* nigrostriatal pathway inhibits the
caudate nucleus and putamen
* CT shows enlarged lateral ventricle due
to degeneration of caudate nucleus
295
# Clinical Anatomy
What is Hemiballismus?
## Footnote
Describe the functions of the basal ganglia to
cognition, emotion and behavior.
Violent, forceful movement confined to one side of the body. It
involves the proximal extremity musculature i.e., muscles of
shoulder and pelvic girdle.
Lesion- subthalamic nucleus, due to thrombosis in the branch of
Posterior Cerebral Artery supplying subthalamus
296
# Clinical Anatomy
What is Parkinsonism?
## Footnote
Describe the functions of the basal ganglia to
cognition, emotion and behavior.
Impairment of voluntary movement
(hypokinesis– delay in initiation of
movements, paucity and lack of
precision of movement)
b. Rigidity– cog wheel
c. Tremor at rest
d. Expressionless face
e. Stooped posture
Caused by
Lesion in the substantia nigra and
damage to nigrostriatal pathway which
uses dopamine as neurotransmitter
Pathology: Cellular loss and
depigmentation of substantia nigra
297
What is the thalamus
## Footnote
Identify the main parts of thalamus and understand their
functional connections
* Large, egg-shaped mass of gray matter
* Forms major part of the diencephalon
* * 4x 1.5x 1.5 cm
* * 2 thalami- situated on each side of the third ventricle
298
What does the thalamus interact with?
## Footnote
Identify the main parts of thalamus and understand their functional connections
**Anterior end**
narrow and rounded
**Posterior end**
expanded to form the pulvinar
**Medial**
forms part of the lateral wall of the third
ventricle
connected to the opposite thalamus by a band of gray matter - interthalamic adhesion
**Lateral**
internal capsule
**Inferior**
continuous with the tegmentum of the midbrain
**Superior**
(Lateral to medial)- caudate nucleus, stria terminalis, thalamostriate vein, fornix
299
Related white matter to the thalamus
## Footnote
Identify the main parts of thalamus and understand their functional connections
Internal medullary lamina-
Vertical sheet of white matter
dividing gray matter of the
thalamus into medial and
lateral halves
* the internal medullary lamina
splits, resembling a Y shape
300
The thalamus is subdivided into ____ parts
## Footnote
Identify the main parts of thalamus and understand their functional connections
3 parts:
anterior part
– medial part
– lateral part
And Smaller nuclear groups
– within the internal medullary
lamina,
– Some on the medial and lateral
surfaces of the thalamus.
301
Anterior part of the thalamus
## Footnote
Identify the main parts of thalamus and understand their functional connections
**Contains the anterior thalamic nuclei**
* Afferent- mammillothalamic tract
* Reciprocal connections with the cingulate gyrus and
hypothalamus.
* Function - emotional tone and recent memory.
302
Medial Part of the thalamus
## Footnote
Identify the main parts of thalamus and understand their functional connections
Dorsomedial nucleus
**Connection** (afferents) from Amygdala
**Connect to** (reciprocal)
- prefrontal cortex
- hypothalamic nuclei.
- interconnected with all other thalamic nuclei
.**Function**: integration of **sensory information**, including somatic, visceral, and olfactory information, and the r**elation of this to emotion and subjective states.**
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Lateral Part of Thalamus: Dorsal Tier of Nuclei
## Footnote
Identify the main parts of thalamus and understand their functional connections
Dorsal Tier of nuclei
– Lateral dorsal nucleus
– Lateral posterior nucleus
– Pulvinar.
* interconnections with –
* other thalamic nuclei and with the
* parietal lobe,
* cingulate gyrus,
* and occipital and temporal lobes.
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Label the Thalamus
## Footnote
Identify the main parts of thalamus and understand their functional connections
Anterior (at the front)
Pulvinar (at the back)
Medial (at the top)
Lateral
Ventral
Lateral divided into dorsal and posterior
Ventral divided into anterior, lateral, venterolateral, posteromedial
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Lateral Part of Thalamus: Ventral Tier of Nuclei:
**Ventral anterior and Ventral lateral nuclei**
## Footnote
Identify the main parts of thalamus and understand their functional connections
* Afferents
– substantia nigra
– Globus pallidus
– Dentate nucleus (VL)
* Efferents
– premotor cortex – Area 4,6
* Influences the activities of the
motor cortex.
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Lateral Part of Thalamus: Ventral Tier of Nuclei:
**Ventral Posterior Nuclei**
## Footnote
Identify the main parts of thalamus and understand their functional connections
Contains the
* VPM
* VPL
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What is the VPL
## Footnote
Identify the main parts of thalamus and understand their functional connections
Afferents
– Medial lemniscus
– Spinal lemniscus
Efferents
– Parietal lobe
– Post central gyrus
* Function: Relay station for touch, pain, temperature and proprioceptive sensations from contralateral body except face
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What is the VPM
## Footnote
Identify the main parts of thalamus and understand their functional connections
Afferents
– Trigeminal lemniscus
– Solitary nucleus
* Efferents
– Parietal lobe
– Post central gyrus through superior thalamic radiation
* Function: Relay station for touch, pain, temperature and proprioception from contralateral face and for taste
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What are the Geniculate bodies
## Footnote
Identify the main parts of thalamus and understand their functional connections
**Medial geniculate body***
A swelling on the posterior surface of the thalamus beneath the pulvinar
* part of the auditory pathway
* Afferent - inferior brachium from the inferior colliculus
* Efferent - auditory radiation to the auditory cortex of the superior temporal gyrus (41,42)
**Lateral geniculate body**
Part of visual pathway
* Swelling on the undersurface of the pulvinar of the thalamus
* 6 layers of nerve cells
* Afferents- optic tract
* Efferent - Optic radiation, which passes to the visual cortex of the occipital lobe.
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What is the blood supply to the thalamus?
## Footnote
Identify the main parts of thalamus and understand their functional connections
Blood supply:
* Posterior communicating arteries
* Basilar artery
* Posterior cerebral arteries
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# Clinical Anatomy
2 important considerations for the thalamus
## Footnote
Identify the main parts of thalamus and understand their functional connections
1) thalamic nuclei are small so that lesions producing highly
specific effects are uncommon
2) Thalamic lesions frequently are accompanied by symptoms
from damage to closely related internal capsule, caudate
nucleus and lentiform nucleus
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# Clinical Anatomy
What is Thalamic syndrome
## Footnote
Identify the main parts of thalamus and understand their functional connections
**Contralateral hemianesthesia**
* Due to damage to VPL and VPM
* Typically, all somatic sensory modalities are affected: light
touch, conscious proprioception, 2-point discrimination &
vibration, and pain & temperature.
**Hyperalgesia or causalgia**
(spontaneous pain with no apparent
stimulation) - seen after a period of recovery from damage to
VPL and VPM (days to months)
* Pain can be severe and intractable.
**Contralateral homonymous hemianopia**
LGB affected
**Movement disorders**
damage of VA/VL nuclei (cerebellum
and basal ganglia project to VA and VL)
* contralateral to the side of the lesion.
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General arrangement in the cerebrum
## Footnote
Describe the white matter of cerebrum and its organisation.
Describe Internal capsule, its parts and related clinical anatomy.
314
What are the **key** White Matter of Cerebral hemisphere
## Footnote
Describe the white matter of cerebrum and its organisation.
Describe Internal capsule, its parts and related clinical anatomy.
**Commissural fibres**– connect corresponding gyri of the two hemispheres:
1) corpus callosum
2) anterior commissure
**Association fibres**-connect one gyrus to another in the same hemisphere
**Projection fibres**– connect more or less vertically
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What are the **Commisures**
## Footnote
Describe the white matter of cerebrum and its organisation.
Describe Internal capsule, its parts and related clinical anatomy.
**Commissural fibres**– connect corresponding gyri of the two hemispheres:
* Corpus callosum
* Anterior commisure
* Posterior commisure
* Commisure of the fornix
* Habenular commisure
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What are the **Internal Capsule**
## Footnote
Describe the white matter of cerebrum and its organisation.
Describe Internal capsule, its parts and related clinical anatomy.
* Projection fibres (white matter) between
* caudate nucleus and thalamus medially
* lentiform nucleus laterally
317
What are the **Internal Capsule**
## Footnote
Describe the white matter of cerebrum and its organisation.
Describe Internal capsule, its parts and related clinical anatomy.
* Projection fibres (white matter) between
* caudate nucleus and thalamus medially
* lentiform nucleus laterally
318
What is the structure of the internal capsule
| label this from memory sometime
## Footnote
Describe the white matter of cerebrum and its organisation.
Describe Internal capsule, its parts and related clinical anatomy.
319
What are the Fibres in internal capsule
| label this from memory sometime
320
What is the limbic system
Set of **interconnected cortical and subcortical** stuctures that form a border (a limbus) **around brain stem **
321
What is the limbic lobe?
The rim of the cerebral cortex
**Grey Matter**
adjacent to the corpus callosum and diencephalon
322
What does the limbic system contain?
The limbic cortex, and subcortical nuclei that are relevant
323
What are the functions of the limbic system?
Remember HOME
H- Homeostatic (autonomic and endocrine)
O- Olfaction
M- Memory
E- Emotions and Drives
324
What is the Papez circuit?
**1937** -
- identify emotion is 4 structures: Hyppocampal, Mamillary body, Ant Nuclei of Thalamus, Gyrus Cinguli
**1970**
- revised, called limbic added: prefrontal gyrus, subcortical structures amygdala, thalamic nuclei etc.
325
What are the components of the Limbic System?
**Limbic Cortex**
parahippocampal gyrus, cingulate gyrus, medial orbitofrontal cortex
**Hippocampal formation**
dentate gyrus, hippocampus
**Amygdala**
Olfactory cortex
**Diencephalon**
hypothalamus, thalamus (ant. nucleus, mediodorsal nucelus
** Basal Ganglia**
ventral striatum (nucelus accumbens, caudate, putamen)
Basal forebrain
Septal nuclei
Tracts that link
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The cerebral cortex has ____ arcs
**3 Arcs:**
**Limbic lobe** (subcallosal area, cingulate gyrus, parahippocampal gyrus)
**Hippocampal formation** (dentate gyrsu, hippocampus, inusium griseum)
**Amygdala**, fibria and fornix
**Connections**
stria terminalis, Medial forebrain bundle, Mammillothalamic tract
**Nuclei**
Amagdyla, Septal nuclei, Mammillary Body, Anterior nucleus of thalamus
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What is the cingulate gyrus?
* Emotional response to pain,
* Assigns emotion to stimuli
* Vocalizing internal states (express emotion)
## Footnote
Damage can result in behaviours such as aggression, shyness and reduced affect.
328
Damage to the cingulate cortex...
can result in behaviours such as aggression, shyness and reduced affect.
Linked to:
early Alzheimer’s disease
schizophrenia
obsessive-compulsive disorder
depression
bipolar disorder
addiction
329
Whats the Indusium griseum
Sheet of grey matter
extends from the paraterminal gyrus via the gyrus fasciolaris to the dentate gyrus
330
What is the Dentate gyrus?
Band of grey matter
lies between fimbria of hippocampus and the parahippocampal gyrus
Seperated by the hippocampal sulcus
331
What is the Hippocampus?
Elongated prominent elevation situated along the floor of the inferior horn of the lateral ventricle
Situated above the dentate gyrus
Anterior end presents a bulbous extremity marked by ridges - ‘pes hippocampi’
332
What are the connections of the Hippocampus?
Papez ciruit:
333
What is the role of the hippocampal formation?
Making new memories & consolidating information from short term to long term memory
334
What happens if teh hippocampal formation is damaged?
Involved in severe mental illness
– Reduced volume in schizophrenia, PTSD, depression
Affected in Alzeimer’s disease
335
What is the fornix?
efferent projection fibres of the hippocampus
(begins as alveus the efferent fibres from pyramidal cells of hippocampus)
336
What is the structure of the Fornix?
The fibres of alveus pass medially on the surface of the hippocampus to form the Fimbria
The fimbria continue as the crura
The crura fuse to form the ‘Body
The body then splits to form columns of the fornix
**FIBRES**
Pre-commissural fibres → septal area
Post-commissural fibres → mamillary body, anterior nucleus of thalamus
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What is the amygdaloid body?
Ovoid **Grey** matter
Situated in the roof of the inferior horn of lateral ventricle
**Input** : from lateral olfactory stria, parahippocampal gyrus
(Visual, auditory, tactile and taste sensory input)
**Output** :
stria terminalis
Supracommisural – septal nuclei
Commisural
Subcommisural – preoptic and anterior nuclei of hypothalamus, anterior perforated substance
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What is the function of the amygdala?
Essential in the control of: love, friendliness, affection, fear, rage, aggression
Electrical stimulation of amygdala can lead to emotional attacks (rage)
339
Damage to the amygdala....
Rabies virus (especially attacks the temporal lobe) leads to violent behavior
Lesions of the amygdala causes reduced ability to identify motivational and emotional significance of events
340
What is the olfactory pathway?
Olfactory nerves
Olfactory bulb
Olfactory tract
Olfactory stria
Prepyriform cortex
Primary olfactory cortex
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Essential structure of the olfactory tract
Medial olfactory stria
-Paraterminal gyrus
-Opposite anterior olfactory nucleus
Lateral olfactory stria
-1' olfactory area
-Prepiriform cortex
-Amygdaloid body
-Nuclei of anterior perforated substance
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