Done by
Dr.Rafid Remthan Al-Temimi
Clinical Radiology
CAMB,DMRD,M.B.Ch.B.,.
المرحلة
:
الثانية
المادة
:
التشريح
ج
امعة ذي قار
/
كلية الطب
الدكتور
رافد
رمثان التميمي
Brain stem, 2
nd
part
2
Pons
• lies inferior to the
midbrain
, superior to the
medulla
oblongata
and anterior to the
cerebellum
• Ventral ( basilar ) part
- Rests upon a bony depression posterior to sella
turica called “ the “clivus “
- Sulcus basilaris in medline for basilar artery.
- Trigeminal nerves exit from the upper border
• Dorsal part
- Form the upper part of rhomboid fossa
hindbrain
pons
Medulla
oblongata
Cerebellum
4
th
vemtricle
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
3
Cerebellar peduncle
1- superior cerebellar peduncle 2-
middle cerebellar peduncle 3- inferior
cerebellar peduncle
- Superior
cerebellar
peduncle
emerges from the superior surface of
pons
- On
each
side,
there
is
the
attachment of middle cerebellar
peduncle
1
2
3
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
4
Cerebellopontine angle
• The
cerebellopontine angle
is a
the
structure at the margin of
cerebellum and pons. Cerebello-
pontine angle is the area of lateral cistern
containing CSF, arachnoid tissue, cranial nerves,
and associate vessels.
• contents :
1.
Facial nerve (CN VII)
2.
Vestibulocochlear nerve (CN VIII)
3.
Flocculus of the cerebellum
4.
Lateral recess of the 4th ventricle
1 2
3
4
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
5
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
6
lesion
normal
Cerebellopontine angle
Pons – Dorsal view
• The dorsal surface of the pons is concealed by
the attached cerebellum.
• The
aqueduct ( arrow )
of the midbrain opens
out at the upper border of the pons into the
cavity of the fourth ventricle, which is mostly
pontine
but medullary
at its lower
end.
• The pontine part of the roof of the ventricle
consists only of a thin sheet of white matter, the
superior medullary velum (1)
, upon which lies
the
lingula of the cerebellum (2)
. The velum is
attached at each side to the
superior cerebellar
peduncles
.
2
1
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
7
Internal organization of Pons
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
8
Internal structure
• Generally the pons contain the following :-
1.
Nuclei of 4 cranial nerves (V, VI, VII & VIII)
2.
Respiratory center nuclei (apneustic & pneumotaxic nuclei / work with MO)
3.
Nuclei & tracts in connection with the cerebellum
4.
Other tracts in connection with other parts of the CNS
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
9
Pons
Basilar part
Dorsal part
White mater
Gray mater
Pontine n.
White mater
Gray mater
Cortico-ponto-
cerebellar
corticonuclear
corticospinal
Superior olivary
complex
( trapezoid
nuclei)
Trapezoid body
Cranial nerve
nuclei ?
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
10
Basilar part
• Grey mater :-
- Pontine nuclei
- Continous with the arcuate
nuclei in medulla
- Afferent :- corticopontine fibers of the
same side
- Efferent :- cortico-ponto- cerebellar
fibers ( thorough the middle cerebellar
peduncle )
- WILL
BE
STUDIED
WITH
CEREBELLUM !!
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
11
Basilar part
• Wite mater :-
• Cerebral cortex internal capsule
crus cerebri dividing to 3
parts !!
1. Cortico-ponto-cerebellar fibers
synapse
with pontine nuclei then go to the
cerebellum through middle cerebellar
peduncle
2. Corticonuclear fibers :-
to motor nuclei of
cranial nerve
3. Corticospinal fibers :-
to form the pyramids
• Most of cortical fibers end in pontine nuclei !
• Middle cerebellar peduncle contains cortico-ponto-
cerebellar fibers of the opposite side only.
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
12
Dorsal ( tegmental ) part
• Trapezoid body and trapezoid nuclei
- Lie in the lower part of the pons &
represent part of the acoustic
pathway
of transverse fibers
from the cochlear
-
Consist
coming
nuclei
bilaterally (especially
- From
these
nuclei
fibers
ascend
as
the
lateral
from the opposite side)
- These fibers end in grey matter nuclei called
nuclei of trapezoid body (superior olivary
complex)
lemniscus
to higher centers
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
13
Trigeminal nerve
Nerve
Modality
Nucleus
location
Distribution
Trigeminal
nerve
GSA
Main
Sensory
nucleus of V nerve
Pons (
posterior part )
Touch and
pressure
Spinal nucleus of V nerve
Pons – C2 level
Pain and
temperature
Mesencephalic nucleus
of V nerve
Pons – midbrain
level
Proprioception
SVE
Motor nucleus of V
nerve
Pons ( medial to
main sensory
nucleus )
Motor to muscles of
mastication,
mylohyoid, anterior
belly of digastric,
tensor veli palatini,
and tensor tympani
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
14
Nuclei of
trigeminal nerve V
Main
motor
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
15
Trigeminal lemniscus
pathway
Crossed or Uncrosses ?!
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Abducent nerve
Nerve
Modality
Nucleus
Location
Distribution
Abducent
nerve
GSE
Abducent
nucleus
Pons ( dorsal
part )
Motor to lateral
rectus to direct
gaze laterally
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
17
Fascial nerve
Nerve
Modality
Nucleus
Location
Distribution
Fascial
nerve
SVE
Motor
nucleus of
VII
nerve
Pons ( lower
part )
Motor to muscles of facial expression and
scalp; also supplie stapedius of middle
ear, stylohyoid, and posterior belly of
digastric
GVE
Superior
salivatory
nucleus
Posteriolater al
to motor
nucleus
Parasympathetic innervation to
submandibular and sublingual salivary
glands, lacrimal gland, and glands of
nose and palate
GSA
Spinal
nucleus of
V
nerve
Pons – c2
Sensation from skin of external acoustic
meatus
SVA
Solitary
tract
nucleus
Lower pons
Taste from anterior two thirds of tongue,
and palate.
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
18
Nuclei of fascial
nerve
VII
1.
Motor nucleus of fascial nerve
VII
2.
Superior salivatory
nucleus
3.
Spinal nucleus of V nerve
4.
Sloitary tract nucleus
1
2
3
4
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
19
UMNL and
LMNL of fascial
nerve
?
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Note :
Vestibulocochlear nerve VIII
will be studied
in the sense of hearing
and equilibrium
and in cranial nerves lecture !
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
21
Unilateral pontine paralysis
• Similar to
lateral medullary syndrome
but
involves the nuclei of CNs in pons !!
1. UMN Paralysis of the opposite side of the body
(
corticospinal tract damage )
2. Internal squint of the same side
( abducent nucleus damage )
Ipsilateral LMN fascial paralysis
( damage to
fascial motor nucleus )
loss
of
fascial and
mastication
4.
Ipsilateral
sensation
muscles
( Trigeminal nerve
nuclei damage )
5. Distributed consciousness
( due
to reticular formation damage )
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
22
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi
23