Download Neuroanatomy

‫‪Neuroanatomy‬‬
‫بسم هللا الرحمن الرحيم‬
‫الكثير من الطالب يعاني مع كيفية مذاكرة مادة النيرواناتومي ‪ ,‬قررت بأذن هللا ‪ ,‬تفريغ ما يقوله البروف‬
‫لطفي ‪ ,‬كون أحد طالب الدفعات السابقة أكد لي أن كل ما يسأل عنه البروف لطفي في االختبارات هو من‬
‫صميم كالمه ‪.‬‬
‫نتمنا اننا نقدر نفيدكم بهذا العمل ‪ ,‬أعذرونا أذا أخطأت في أي معلومة ‪.‬‬
‫العمل راح يكون على شكل باوربوينت حتى يسهل ألي أحد تصحيح خطأ لو وجد ‪ ,‬أو أضافة معلومة من‬
‫عنده ‪ ,‬العمل عبارة عن شرح ساليدات الدكتور لطفي كونها مو كافية ‪.‬‬
‫حقوق الطبع غير محفوظة ‪ ,‬ويحق لكل طالب أن يعتبر الساليدات حقته يعمل بها ما يريد ‪‬‬
‫أخوانكم ‪ :‬عدنان توفيق اليوسف و علي غالب الهاشم‬
1- CEREBELLLUM
1st and 2nd lectures
Introduction
The cerebellum plays a very important role in the control of posture and voluntary
movement . It unconsciously influence the smooth contraction of voluntary muscle
and carefully coordinates their action ,together with the relaxation of their
antagonists.
The cerebellum is situated in the posterior cranial fossa and is covered superiorly by
the tentorium cerebelli. It is the largest part of the hindbrain and lies posterior to the
4th ventricle , the pons , and the medulla oblongata .
It consist of two cerebellar hemispheres joined by narrow median Vermis .
The cerebellum is connected to the posterior aspect of the brain stem by 3
symmetrical bundles of nerve fibers called : superior , middle , and inferior
cerebellar
peduncles .
The cerebellum is divided into 3 main lobes : anterior lobe , the middle lobe , and the
flocculonodular lobe .
From prof. Lutfi slides
From prof. Lutfi slides
From prof. Lutfi slides
Con…
The cerebellum plays a very important role in the control of posture and voluntary
movement . It unconsciously influence the smooth contraction of voluntary muscle
and carefully coordinates their action ,together with the relaxation of their
antagonists.
Each cerebellar hemisphere controls muscular movement on the same side of the
body and that the cerebellum has no direct pathway to the lower motor neurons but
exerts its control via the cerebral cortex and brain stem.
Function of Cerebellum
The function of cerebellum is to maintain muscle tone .
Note that “when we mention muscle tone we must mention the posture”
Also have an important role in equilibrium and balance .
Maintain
Posture
Sequential
Movement
Muscle tone
Cerebellum
Balance
Equilibrium
What does the cerebellum consist of ?
The cerebellum consist of 2 cerebellar hemisphere connected to each others by
VERMIS.
The cerebellum connect to the brainstem by 3 bundles of nerve fibers :1-superior c. peduncle : connect it to Midbrain
2-middle c. peduncle : connect it to Pons
3-inferior c. peduncle : connect it to Medulla oblongata .
The cerebellum was divided into :- lobs and fissure .
Cerebellum has 3 lobs :
1-anterior lobe
2-posterior lobe “middle,largest”
3-flocculonodular lobe
And the fissures are :
1-primary “separates anterior from posterior”
2-uvulonodular “separates posterior from flocculonodular”
From prof. Lutfi slides
From prof. Lutfi slides
Con…
*Flocculonodular lobe : receive incoming vistibular fiber .
*There is connection between the flocculonodular lobe and vestibular nuclei
*in cerebellum , the gray matter is on the surface , and the white matter is
inside , “opposite to brain and spinal cord” , of course the inner white
matter is not pure due to presence of INTRACEREBELLUM NEUCLEI .
Cerebellar cortex
*there are 3 layers of the outer cortex :1-molecular layer
2-purkinje layer
3-granular layer
*The parkinje cell is type 1 golgi cell
*the dendrite of the purkinje layer is going out to the molecular layer .
I. Cerebellar cortex
Cerebellar Gray matter
Molecular
Purkinje
Granular
layer
layer
layer
Basket cells
Stellate cells
From prof. Lutfi slides
Granule cells
Golgi cells
From prof. Lutfi slides
Con…
The molecular layer has 2 types of cells :1-basket cells
2-stellate cells
These cells synapse with the dendrite of the purkinje cell .
The purkinje cell’s axon go out form cortex ,
“the only efferent fibers that leave the cerebellar cortex are the axons of
purkinje cell” > they go to INTRACELLEBLAR NUCLEI .
Note : not all of the purkinje cell axon are going to Intracelleblar but few of
them, specially from the Flocculonodular lobe are going directly to the
vestibular nuclei .
* The granular cell layer has 2 types of small cells :1-granular cells
2-golgi cells
Con…
Granular cell has very little cytoplasm and very dens nuclei , they are small
with very tall dendrites reach the molecular layer.
The dendrites of the granular cell synapse with purkinje cells.
Golgi cells are larger than granular cells .
There are 2 type of afferent fiber that reach the cerebellar cortex :1-climbing fiber
2-mossyl fiber
Climbing fiber :
They go to the molecular layer and synapse with parkinje cells
Note: each parkinje cell synapse with ONE climbing fiber ,but one climbing
fiber may synapse with up to 10 parkinje cells .
The climbing fibers are coming from olivary nuclei .
Con…
Mossy fiber :
They originate from the anterior and posterior spinocerebellur tract ,
vistibulocerebellar , reticilocerebellar , cuneocerebellar , etc.
And they end by synapses with the granular dendrites .
# the mossy and climbing fibers have stimulatory effect on the purkinje cell
but the axon of the purkinje cell to the intracerebellar nuclei are
inhibatory , and this inhibtion effect is due to neurons found in the
cerebellar cortex that synapse with purkinje cell such as golgi cell , basket ,
stellate and granular.
The affect of them on the purkinje cell are inhibitory and the result is that the
axon of the purkinje cell is inhibitory .
Note: the affarent fiber “ mossy and climbing” before they enter the
cerebellar cortex they give collateral fibers to the intracerebellar nuclei.
Con...
There are no direct fibers from the cerebellum to the spinal cord , they deal
with other brain structure to mediates its function such as : red nucleus ,
reticular formation , thalamus and vestibular nuclei.
II. Intracerebellar nuclei
Fastigial
Globose
Emboliform
Dentate
nucleus
nucleus
nucleus
nucleus
From prof. Lutfi slides
From prof. Lutfi slides
Location of intracerebellar nuclei
Vermis & flocculonodular lobe
Fastigeal nucleus
Paravermal zone of the hemispheres
Globose & Emboliform nuclei
Lateral zone of the hemispheres
Dentate nucleus
From prof. Lutfi slides
Afferent & efferent fibers of the
cerebellum
In cerebellum the are nerve fiber which enter the cerebellum , and the other go out
from it .
The fibers which enter the cerebellum called AFFERENT FIBERS , and these fibers are
come from SPINAL CORD , VESTIBULAR NERVE , VESTIBULAR NUCLEI, AND CEREBRAL
CORTEX .
The fibers which go out from the cerebellum called EFFERENT FIBERS , this fibers go
to the RED
NUCLEUS , VESTIBULAR NUCLEI , THALAMUS , AMD RETECULAR FORMATION .
WE WILL MENTION THESE PATHWAY IN THE NEXT SLIDES
Functions of the cerebellum
1-Maintaining balance & equilibrium
Lateral vestibular nuclei & RF
Vestibulocerebellum
(flocculonodular lobe)
Vestibular nerve
From prof. Lutfi slides
CON..
By the vestibular nerve , the cerebellum maintain the balance and equilibrium
, the ganglion of the vestibular nerve are located in the internal acoustic
meatus , its peripheral fibers come from semicircular canal , sacule and
utricle . MOST of the fibers end in the vestibular nuclei , BUT SOME OF
THEM GO DIRECT TO THE CEREBELLUM FROM THE INFERIOR CEREBELLAR
PEDUNCLE.
There are fibers go from cerebellum ‘ efferent fibers from fastigeal nucleus’ to
the vestibular nuclei and retecular formation .
Functions of the cerebellum
2-Control of muscle tone & coordination of muscular
activity (unconscious proprioception)
Vestibular nuclei
Reticular
formation
Red nucleus
Thalamus
Spinocerebellum
(Vermis & paravermal
zone)
Spinal cord
From prof. Lutfi slides
CON..
 ‫قوم سوي لك كوب شاي و تعال كمل مذاكرة‬
In this pathways “ from spinal cord to the cerebellum “ we have the fibers which reach
the cerebellar cortex : CLIMBING FIBERS AND MOSSY FIBERS .
1- CLIMBING
Only one pathway as we saied before spino-olivary-cerebro-olivary cerebellar tract .
They collect in inferior olivary nuclei and then enter the cerebellum via INFERIOR
CEREBELLAR PEDUNCLE .
The give collateral branch to the intracerebellar nuclei before go to the cerebellar
cortex .
Con..
2- MOSSY
The other pathway :
A- anterior spinocerebellar tract
Its axon enter the spinal cord from muscle spindle ,tendon and joint receptor and synapse
with NUCLEUS DORSALIS ‘ CLARKEKS NUCLEI’ , MOST OF AXONS CROSS TO THE OPPOSITE SIDE
.this fibers enter the cerebellum via SUPERIOR CREBELLAR PEDUNCLE as mossy fibers in
cerebellar cortex .
It gives collateral branch to the intracerebellar nuclei .
It is belived that those fibers cross back within the cerebellum .
B- posterior spinocerebellar tract :
Same as anterior , but these fibers go direct to the cerebellum ‘ do not cross and cross back ‘
and they enter via inferior cerebellar peduncle.
C-cuneocerebellar
NOTE: all the fibers that mention before come from C8 BELOW TO L3 spinal segment EXCEPT
THIS PATHWAY which come from above C8 segment.
Con...
These fibers collected in Cuneatus nucleus , and enter the cerebellum via
inferior cerebral peduncle .
From prof. Lutfi slides
Functions of the cerebellum
3-Monitoring of sequential motor activity
Thalamus
(VL nucleus)
Cerebral
cortex
Pontine nuclei
Inferior olivary nucleus
& reticular formation
Pontocerebellum
(Lateral zone)
From prof. Lutfi slides
From prof. Lutfi slides
Afferent Input
Climbing
fibers
Mossy
fibers
• Olivocerebellar
fibers
• All other
afferents
From prof. Lutfi slides
From prof. Lutfi slides
Cerebellar efferent fibers
From prof. Lutfi slides
Cerebellar peduncles
SCP
• mainly efferent:
• Cerebellothala
mic &
cerebellorubral
fibers
• Some
afferents:
ventral
spinocerebellar
tract &
tectospinal
MCP
• Only afferent:
Pontocerebell
ar fibers
ICP
• mainly
afferent:
OSCV
• Some
efferent to
vestibular
nuclei &
reticular
formation
From prof. Lutfi slides
Summary of cerebellar
connections
Output
Spinal cord
Vestibular nerve
Cerebral cortex
Proprioceptive 
information from
muscles & joints
Information 
about location &
movement of
head in space
Plans of motor 
activity
Cerebellum
Thalamus 
(VL)
brainstem
Efferent
Red nucleus
Vestibular
nuclei
Reticular
formation
Afferent
Input
From prof. Lutfi slides
Blood supply
Three cerebellar •
arteries:
Superior cerebellar .1
artery
Anterior inferior .2
cerebellar artery
(AICA)
Posterior inferior .3
cerebellar artery
(PICA)
From prof. Lutfi slides
Blood supply (cont.)
Venous drainage: •
into adjacent venous
dural sinuses
From prof. Lutfi slides
Clinical case
A 56-year-old woman was examined 
by a neurologist and was found to
have the following signs:
Irregular swaying gait •
Diminished tone of the muscles of •
her right upper & lower limbs
Right sided tremor •
Difficulty in performing finger-to- •
nose test using her right hand
CT brain revealed a right-sided 
cerebellar tumor
So its main
function is:
Control of muscle
tone & coordination
of voluntary
movement
From prof. Lutfi slides
Analysis of the clinical case
1- Irregular swaying gait :
‫ بحيث ان المريض يسير مع انحراف او ميالن الى الجهة المصابة‬, ‫يكون هنالك خلل في طريقة المشي‬
“hypotonia” >>(lose of muscle tone and posture )
2- Diminished tone of the muscle of the right upper and lower limps:
In normal the muscle tone must be resilience and firmness but if the muscle lose it’s
tone , it’ll be like dough .
Now , how do we test for muscle tone :
A- suppose that , the patient has right side lesion , passively flex and extend his arm or
his leg , and then compare it to the opposite side , then you will notice that the side
which has a lesion will show no resistance , no firmness or resilience .
3- right side tremor :
Due to lack of coordination in action of antagonist muscle , for example : if I flex my
elbow , the Biceps muscle contract and the triceps muscle relax , but if there is no
coordination , triceps muscle wont accept to relax , and then both muscle will contract
!!! Leading to tremor .
There are many causes of tremor :
A- parkinsonism
B- thyrotoxicosis
C- cerebellar lesion
* How can we differentiate between them ?
A-In parkinsonism : if the patient is calm , there will be tremor but when he/she
wants to perform an action , the tremor will go away , also in sleep there is no
tremor .
B- thyrotoxicosis : ask the patient to put his/her hands straight , and put up to them
a paper then you will see the both hands are shaking .
C- cerebellar lesion : it’s hidden , Ie . At rest the patient doesn’t show an obvious
tremor , but if he/she try to do something it becomes exaggerated . One way to
testing it , is to ask the patient to touch his/her nose by the lesioned side of his/her
body . If you ask hem to do it by the non-lesioned side “hand” he/she will smoothly
touch his/her nose ,but by the lesioned side , when he/she become close to his/her
nose will notice that his hand will go faraway from his nose , or touch it with
roughness . So, this type of tremor called intention tremor .
4- Difficulty in performing finger to nose test using her right hand due
to DYSDIADOCHKINESIA
Another symptoms may present “ not related to our
clinical case “
*Also in the cerebellar lesion , due to loss of coordination the patient will suffer
from NYSTAGMUS, lack of coordination between median and lateral rectus , also
, the patient will show difficulty in speaking”DYSARTHRIA” due to lack of
coordination of Laryngeal muscle , tongue muscle and palatal muscle . The
speech feature of the patient will be prolong , discontinuous and finally explosive
all these symptoms are due to ATAXIA .
*the patient head is often rotated and flexed , and the shoulder on the side of
the lesion is lower than the normal side .
*the patient also assumes a wide base when he/she stands and often stiff legged
to compensate lose of muscle tone .
*also the patient will show DYSDIADOCHKINESIA which is inability to performe
alterative movement regularly and rapidly . “in book P:244”
Lesions of the cerebellum
Congenital agenesis or hypoplasia •
Acute alcohol poisoning •
Trauma •
Infection (meningitis, encephalitis) •
Vascular disorders •
Tumors (medulloblastoma, meningioma, glioma) •
Multiple sclerosis •
From prof. Lutfi slides
Signs & symptoms
of cerebellar lesions
Loss of muscle tone
Remember!
These occur
on the
ipsilateral
side of the
body
Incoordination of
voluntary muscular
activity (ataxia)
From prof. Lutfi slides
Hypotonia
Postural changes
Abnormal gait
Intention tremor
Decomposition of movement
Dysdiadochokinesia
Pendular knee jerk
Nystagmus
dysarthria
The specific deficits that result depend on which 
functional component of the cerebellum is most
affected:
lesions of the vestibulocerebellum  affect posture •
& balance
Lesions of the spinocerebellum (vermis syndrome) •
 truncal ataxia
Lesions of the pontocerebellum (cerebellar •
hemisphere syndrome)  inappropriate control of
sequential motor movements
From prof. Lutfi slides
Summary
Cerebellum is controlled by contralateral cerebral •
hemisphere
Cerebellum controls the ipsilateral half of the •
body
Cerebellar lesions do not lead to paralysis but •
produce motor dyskinesia (ataxia)
Cerebellar lesion produces hypotonia but no •
atrophy
Cerebellar lesion does not produce loss of •
sensation
From prof. Lutfi slides
Summary (cont.)
Acute lesion produces sudden symptoms •
Chronic lesion can be compensated by other •
parts of CNS
Cerebellum has no direct neuronal connection to •
LMNs
Cerebellum does not control the smooth muscles •
Cerebellum cannot initiate voluntary movement •
Wish you all best
From prof. Lutfi slides
Nice information not related to the
cerebellum
1- if an old person complain from epigastric pain you should first think about HEART
PROBLOMES.
2- If a young person complain from heart pain you should think first about EPIGASTRIC
PROBLEMS.
3-Any patient have COMA should this occur due to these causes :
You can remember them from the VOWEL letters
A: Alcoholism or Apoplexy
E: Encephalitis or Epilepsy
I: Infection or Insulinism
O: Opiate ‘ drugs’
U: Uremia ‘ due to kidney failure’