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, 3
rd
part
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
Medulla oblongata
• The medulla oblongata is the part of the
brainstem between the pons and spinal cord
• it extends through the foramen
magnum to the level of the atlas.
• Medullar is vital for our function, without
medulla we die.
• Above the foramen magnum it is
embraced
dorsally by the cerebellar hemispheres.
1. The lower end which contains the upward
continuation of the central canal of the
spinal cord is the
‘closed part of the
medulla’,
2. the upper end, where the canal comes to the
surface as the lower part of the floor of
the fourth ventricle, is the
‘open part’.
1
2
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
Medulla oblongata
• MO is about
3 cm
( lowest 3 cm of the brainstem )
• it extend from the pronto-medullary junction until
plane below foramina magnum for about 0.5 cm.
• Medulla spinalis have a central canal which
prolonged into its lower half to open in the four
ventricle at its upper half.
• CSF is encircle the MO from outside
( subarachnoid space ) and inside
( central canal ).
• MO is
between the
( anterior
two lobes of
cerebellar
cerebellum
notch )
Closed part
Open part
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
Medulla oblongata
• Ventrally the upper part of the medulla is
deeply grooved
in the midline, with a bold
convexity on either side,
the pyramid (1)
,
due to
the contained corticospinal fibres.
• Lateral to the pyramid is another convexity,
the olive (2) , due to
the underlying inferior
olivary nucleus.
• Lateral to the olive the lateral
surface of the medulla is formed by the
inferior cerebellar peduncle,
which enters
the cerebellum medial to and below the
middle peduncle.
1
2
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
Cranial nerves
• 2 exit from the midbrain
• 4 exit from the bones
• 4 exit from the medulla
• From medulla
1. Glossopharyngeal nerve IX
2. Vagus nerve X
3. Spinal accessory nerve XI**
4. Hypoglossal nerve XII
**although it exit through medulla it have NO nuclei in it
( note : cranial accessory nerve is consideres as part of
vagus )
IX
XII X
XI
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
Cranial nerves
• From the 4 cranial nerves that exit
through medulla
• 1 exit between pyramid and olive
XII
• The other 3 exit between olive and ICP
IX,X,XI
IX
XII X
XI
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
Medulla oblongata
• Dorsally the lower part of the floor of the fourth
ventricle forms the upper part of the medulla ,
here the roof of the ventricle is ependyma and
pia mater.
• At the lower corner of the diamond- shaped
floor
the hypoglossal trigone
(1)
is adjacent to the midline, with the
vagal
trigone (2)
lateral to it. Higher up and at the
lateral corners of the diamond is the vestibular
area and the medullary striae.
• In the lower or closed part of the medulla, the
fourth ventricle has become narrowed to the
tiny central canal, and the external dorsal
surface shows small elevations,
the gracile (3)
and cuneate (4) tubercles
, the former being
medial to the latter.
1
2
3
4
CC
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
Internal structure
NOTE
We will study cross section firstly in closed part then in
open part !!
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
Closed part of medulla
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
Closed part ofmedulla
Gray mater
White mater
Spinal nucleus of V. nerve
Spinal accessory nucleus
Nucleus graciles
Nucleus cuneatus
Sensory
Motor
Pyramidal decuss.
Spinal tract of V nerve
Lateral ST tract
Anterior & posterior SC tract
Internal arcuate fibers*
Medial lemniscus begining
*internal arcuate fibers = DC-ML system
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
spinal nucleus of the trigeminal nerve
• Arrow !!
• Extend from
pons to C2
• Pain, temperature and crude
touch from the ipsilateral H&N
• general somatic sensation corresponding
to
anteriolateral system !!!
• V, VII, IX,X
have connections with it.
Spinal accessory nucleus
• Only nuclei of spinal accessory nerve XI
• Reach lower medullary levels
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
gracile and cuneate nuclei
• The
gracile and cuneate nuclei
underlie the corresponding tubercles of the dorsal
surface of the lower medulla.
• They contain the cell bodies on which the incoming
fibres of the gracile and cuneate
tracts
of
the
spinal cord terminate
• the nuclei give origin to the medial
lemniscus.
G
C
DC-MLT
STT
ALT
Brain stem
Spinal cord
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
White mater – pyramidal decussation level
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
White mater – medial Leminscus decussation level
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
open part of medulla
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
open part of medulla
Gray mater
Inferior olivary nucleus
Arcuate nucleus
Spinal nucleus of V nerve
Nucleus ambiguius
Nuclei of solitary tract
Lateral vestibular nuclei
Cochlear nuclei
Inferior salivatory nucleus
Nucleus of hypoglossal n.
Dorsal nucleus of vagus n.
CN IX,X,XII nuclei
Will be studied in cerebellum !!
Will be studied in 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
Open medulla – inferior peduncle level
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
Modalities of CN
?
• 1- motor :-
• A- to skeletal muscle
-
General : muscle of somite origin
GSE
-
Special : muscle of branchial origin
SVE
• B- to viscera ( parasympathetic )
GVE
-
To glands ( secretomotor )
-
To smooth muscle
• 2- sensory
• A- From body
-
General : 3 types of sensation
GSA
-
Special : vision, hear & balance
SSA
• B- From viscera
-
General : visceral pain and spasm
GVA
-
Special : test and smell
SVA
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
Parasympathetic CN and their nuclei and ganglion
Parasympathetic CN
Nuclei
Ganglion
Oculomotor nerve III
Acessory oculomotor
nucleus
Ciliary gangliom
Fascial nerve VII
Superior salivatory nucleus
Ptrygopalatine ganglia
+
Submandibular ganglia
Glossopharyngeal nerve IX
Inferior salivatory nucleus
Otic ganglion
Vagus nerve X
Dorsal nucleus of vagus nerve
Superior and inferior
ganglion of vagus 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
Glossopharyngeal nerve IX
Nerve
Modality
Nucleus
Position
Distribution
Glosso-
pharyngeal
nerve
SVE
Nucleus
ambigius
Medulla
Motor to stylopharyngeus that
assists with swallowing
GVE
Inferior
salivatory
nucleus
Medulla
Parasympathetic innervation
to parotid gland
GVA
Solitary nucleus
Lower
medulla
Visceral sensation from parotid
gland, carotid body and sinus,
pharynx, and middle ear
SVA
Taste from posterior 1/3
of tongue
GSA
sensory nucleus of
trigeminal nerve
Pons – C2
Cutaneous sensation from
external ear
Common sensation from
posterior 1/3 of tongue
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
Glossopharyngeal nerve IX
Nerve
Modality
Nucleus
Position
Distribution
Vagus
nerve
SVE**
Nucleus ambigius
Medulla
Motor to constrictor muscles of pharynx,
intrinsic muscles of larynx, muscles of
palate (except tensor veli palatini), and
striated muscle in superior two thirds of
esophagus
GVE
Dorsal vagus nuclei
Medulla
Smooth muscle of trachea, bronchi,
and digestive tract,cardiac
muscle
GVA
Solitary nucleus
Lower
medulla
Visceral sensation from base of tongue,
pharynx, larynx, trachea, bronchi, heart,
esophagus, stomach, and intestine
SVA
Taste from epiglottis and palate
GSA
Sensory nucleus of
trigeminal nerve
Pons – C2
Sensation from auricle, external acoustic
meatus, and dura mater of posterior
cranial fossa
**Cranial part of accessory nerve XI
University Of Thi-Qar
College Of medicine
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Spinal accessory nerve
• Two parts
1.
Cranial part ( from N ambigius )
X
2.
Spinal part
-
Ascend from upper cervical cord
-
Enter F. magnum to join the cranial part.
-
Separate just below the Jagular
foramina.
-
PCT supply platysma and SCM !!
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
Hypoglossal n.
• Hypoglossal nucleus lies
in
lower medulla
• Give XII nerve fibers
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
Medullary autonomic centers
• Cardiovascular centers :-
• 1-
cardioinhibitary
and
cardiostimulatory centers affect the
rate and force of cardiac contraction.
• 2- vasomotor centers affect the smooth
muscle fibers tone.
• Respiratory centers :-
• Recive input from pons
• Others :-
• Emesis
• Deglutition
• Coughing
• Hiccupping
• Sneezing
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
Blood supply of medulla
• The medulla
is
supplied
ventrally
by branches of the
vertebral and basilar arteries, and
laterally and dorsally
by the posterior
inferior cerebellar artery.
• The veins drain
dorsally
to the occipital
sinus and
ventrally
into the basilar
plexus of veins and the inferior petrosal
sinus.
• The
medullary
veins
communicate with
the
spinal
veins.
Posterior
inferior
cerebellar a.
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
Blood supply of medulla
Aertery
distribution
Loss of supply lead to:
Anterior spinal artery
(branch of vertebral a. )
supply the region next to the midline
i.e. the part containing the
pyramid,medial lemniscus
and hypoglossal nucleus
Medial medullary syndrome
Posterior inferior
cerebellar a. ( branch of
vertebral a. )
Lateral and dorsal sides of the MO
lateral medullary syndrome
‘syndrome of the posterior
inferior cerebellar artery’.
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
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
Thank you
University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
nd
stage
Dr.Rafid Al-Temimi