قراءة
عرض

Done by

Dr. Rafid Remthan Al -Temimi
Clinical Radiology
CAMB,DMRD, M.B.Ch.B .,.
المرحلة : الثانية
المادة : التشريح
امعة ذي قار ج/ كلية الطب
الدكتور
رمثان التميمي رافد
Brain stem, 3 rd part

University Of Thi -Qar

College Of medicine
Anatomy lecture . 2nd 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 . 2nd 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
( su b arach noid space ) and inside
( central canal ).
• M O is b etw ee n the
( anterior
tw o lobes of
ce rebellar cerebellum
notch )
Closed part
Open part
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd 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 .
• La te ral to th e oli v e th e lat e ral
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 . 2nd 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 . 2nd 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 e xi t b e tw e e n p y ra m id 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Closed part of medulla

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 . 2nd 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 C 2
• 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd 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 . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Glossopharyngeal nerve IX

Nerve Modality Nucleus Position Distribution

Glosso -

p h a ryn g e al
nerve
SVE Nucleus
ambi gi us
Medulla Motor to stylopharyngeus that
assists with swallowing
GVE Inferior
sali vat ory
nucleus
Medulla Parasympathetic in nervati on
to pa rot id gland
GVA

Solitary nucleus

Lower
m edul la
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 . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Glossopharyngeal nerve IX

Nerve Modality Nucleus Position Distribution

V agus

ne rv e

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.
- Sep arate ju st below the Jagul ar
foramina.
- PCT  supply platysma and SCM !!
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd 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 . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Medullary autonomic centers

• Cardiovascular centers :-
• 1 - cardioinhibitary and
cardio stimul ato ry ce nt e rs affe ct th e
rate and force of cardiac contraction.
• 2 - vasomo tor ce n te rs affec t 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 . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Blood supply of medulla

• Th e m e d u lla is su p p lied
v e n trally b y b ranches 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 v eins
communicate with the spi n al
veins.
Posterior
inferior
cerebellar a.
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd 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 spi n al ar te ry
(b ranch of vertebral a. ) supply the region next to the midline
i.e. the part containing the
p yram id ,m e d ial lemniscus
and hypoglossal nucleus

M e d ial m e d u lla ry syndrome

Posterior inferior
ce rebella r a. ( b ranch o f
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 . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

University Of Thi -Qar

College Of medicine
Anatomy lecture . 2nd 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 . 2nd stage
Dr.Rafid Al -Temimi


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