Download - BRAINSTEM-Lec by Emma
-
8/14/2019 BRAINSTEM-Lec by Emma
1/51
BRAINSTEM
Lecturer: Emmaruth B. Bautista, PTRP
-
8/14/2019 BRAINSTEM-Lec by Emma
2/51
MEDULLA OBLONGATA
Upper half- cavity of 4
th
ventricleLower half- central canal of SC
ANTERIOR SURFACE OF MEDULLA:AMF- anterior median fissure of SC
PYRAMIDS- one ach side of AMF of SC
Swelling Tapers inferiorly: bundles of nerve fibers,
corticospinal tracts
DECUSSATION OF PYRAMIDS
-
8/14/2019 BRAINSTEM-Lec by Emma
3/51
1. Anteriormedian fissure
2. Olive
3. Pyramids 4.Cerebellum
-
8/14/2019 BRAINSTEM-Lec by Emma
4/51
MEDULLA OBLONGATA
OLIVES- posterolateral to pyramidsGroove between PYRAMIDS & OLIVE:
Rootlets ofHYPOGLOSSAL N.
INFERIOR CEREBELLAR PEDUNCLES-Posterior to olives
Connects MO-cerebellum
Groove between OLIVES & INFERIORCEREBELLAR PEDUNCLES:
Rootlets ofGLOSSOPHARYNGEAL, VAGUS &
CRANIAL ROOTS OF ACCESSORY N.
-
8/14/2019 BRAINSTEM-Lec by Emma
5/51
1.Glossopharyngeal
nerve
2.Vagus nerve 3.Hypoglossal nerve
4.Accessory nerve
5.First cervical spinal
nerve
6.Spinal root of accessory
nerve
-
8/14/2019 BRAINSTEM-Lec by Emma
6/51
MEDULLA OBLONGATA
POSTERIOR SURFACE OF Medulla Oblongata:Superior half- forms lower part of floor of 4th
ventricle
Inferior half- continuous with SC & possesses
posterior median sulcusGRACILE TUBERCLE- on each side of posterior
median sulcus
Elongated swellingProduced by GRACILE NUCLEUS
-
8/14/2019 BRAINSTEM-Lec by Emma
7/51
-
8/14/2019 BRAINSTEM-Lec by Emma
8/51
MEDULLA OBLONGATA
CUNEATE TUBERCLE- lateral to gracile nucleusProduced by underlying: CUNEATE
Internal Structure:Considered at 4 levels:
1. pyramids
2. lemnisci
3. olives
4. just inferior to pons
-
8/14/2019 BRAINSTEM-Lec by Emma
9/51
-
8/14/2019 BRAINSTEM-Lec by Emma
10/51
LEVEL OF DECUSSATION OF
PYRAMIDS
Great motor decussationSuperior part of MO: corticospinal fibers occupy &
form the pyramid
Inferiorly: about of fibers cross median plane &continue down the SC in the lateral white column as
LATERAL CORTICOSPINAL TRACT ( crosses
midline )
-
8/14/2019 BRAINSTEM-Lec by Emma
11/51
-
8/14/2019 BRAINSTEM-Lec by Emma
12/51
FASCICULUS GRACILLIS &
CUNEATUSContinue to ascend superiorly posterior to central
gray matter
Appears as posterior extensions of central gray
matter
Substantia gelatinosa in posterior gray column
becomes continuous with inferior end ofNUCLEUS
OF SPINAL TRACT OF TRIGEMINAL N.
-
8/14/2019 BRAINSTEM-Lec by Emma
13/51
LEVEL OF DECUSSATION OF
LEMNISCI
Great sensory decussationTakes place anterior to central gray matter &
posterior to pyramids
Have bee formed from: INTERNAL ARCUATE
FIBERS
Which has emerged from the anterior aspect of
the NUCLEUS GRACILIS & NUCLEUS
CUNEATUS
-
8/14/2019 BRAINSTEM-Lec by Emma
14/51
LEVEL OF DECUSSATION OF
LEMNISCI
NUCLEUS OF SPINAL TRACT OF TRIGEMINALN.-
lies lateral to internal arcuate fibers
SPINAL TRACT OF TRIGEMINAL N.- Lies lateral to nucleus
LATERAL & ANTERIOR SPINOTHALAMIC
TRACTS & TECTAL TRACTS
Lateral to decussation of lemnisci
Collectively known as: SPINAL LEMNISCUS
-
8/14/2019 BRAINSTEM-Lec by Emma
15/51
LEVEL OF DECUSSATION OF
LEMNISCI
SPINOCEREBELLAR, VESTIBULOSPINAL &RUBROSPINAL TRACTS-
Situated anterolateral region of Medulla Oblongata
-
8/14/2019 BRAINSTEM-Lec by Emma
16/51
LEVEL OF OLIVESTransverse section passes across inferior part of 4th
ventricle
Amount of gray matter has increased at this level
OLIVARY NUCLEAR COMPLEX:
INFERIOR OLIVARY NUCLEUS Largest nucleus of this complex
Gray matter shaped-bag, mouth directed mediallyResponsible for elevation on surface of medulla called
OLIVES
-
8/14/2019 BRAINSTEM-Lec by Emma
17/51
OLIVARY NUCLEAR COMPLEX
Smaller dorsal & medial accessory olivary nuclei
are also present
Send fibers medially across midline to enter
cerebellumSPINO-OLIVARY TRACTS
Function is associated with voluntary movement
-
8/14/2019 BRAINSTEM-Lec by Emma
18/51
VESTIBULOCOCHLEAR NUCLEIVESTIBULAR COMPLEX:
1. medial vestibular nucleus
2. inferior vestibular nucleus
3. lateral vestibular nucleus
4. superior vestibular nucleus
2 COCHLEAR NUCLEI:
1. anterior cochlear ( anterolat of ICP )
2. posterior cochlear ( post of ICP )
-
8/14/2019 BRAINSTEM-Lec by Emma
19/51
NUCLEUS AMBIGUUS
Large motor neurons
Situated deep w/in reticular formation
Joins CN IX, X, XI ( cranial part ) distributed to
voluntary muscles
CENTRAL GRAY MATTER
Lies beneath floor of 4th ventricle ( M-L )
1. hypoglossal nucleus 2. dorsal nucleus of vagus
3. nucleus of tractus solitarius
4. medial & inferior vestibular nuclei
-
8/14/2019 BRAINSTEM-Lec by Emma
20/51
ARCUATE NUCLEI
Inferior displaced pontine nuclei
Efferent fibers to cerebellum- EXTERNALARCUATE FIBERS
PYRAMIDS CORTICOSPINAL & CORTICONUCLEAR FIBERS
MEDIAL LEMNISCUS Flattened tracts on each side of midline posterior to pyramid
Emerge from decussation of lemnisci
Convey sensory information to thalamus
-
8/14/2019 BRAINSTEM-Lec by Emma
21/51
MEDIAL LONGITUDINAL FASCICULUS
Forms small tract of fibers situated on each side of
midline posterior to medial lemniscus & anterior tohypoglossal nucleus
INFERIOR CEREBELLAR PEDUNCLES In posterolateral corner on lateral side of 4th ventricle
SPINAL TRACT OF CN V & ITS NUCLEUS On antermedial aspect of ICP
ANTERTIOR SPINOCEREBELLAR TRACT
Between inferior olivary & nucleusof spinal tract of CN VRETICULAR FORMATION
Deep posterior to olivary nucleus
-
8/14/2019 BRAINSTEM-Lec by Emma
22/51
1.Nuclei of oculomotor
nerve
2.Trochlear nucleus
3.Pons 4.Fourth ventricle
5.Abducent nucleus
6.Vestibular nucleus
7.Medial longitudinal
fasciculus
-
8/14/2019 BRAINSTEM-Lec by Emma
23/51
1.Inferior cerebellar
peduncle
2.Floor of fourth ventricle
3.Hypoglossal nucleus 4.Medial longitudinal
fasciculus
5.Reticular formation
6.Medial lemniscus
7.Arcuate nuclei
8.Inferior olivary nucleus
9.Pyramids
-
8/14/2019 BRAINSTEM-Lec by Emma
24/51
IX, X & Cranial part of Accessory N.
can be seen running forward & lateral through
reticular formation
HYPOGLOSSAL N.
Run anterior & lateral through reticular
LEVEL JUST INFERIOR TO PONSNo major changes
Lateral vestibular nucleus has replaced
inferior vestibular nucleus
Cochlear nucleus now are visible on anterior
& posterior surface of ICP
-
8/14/2019 BRAINSTEM-Lec by Emma
25/51
PONSGROSS APPEARANCE:
Convex anterior surface
Transverse fibers converge to form MCP
BASILAR GROOVE
lodges basilar artery
On anterolat side: emerges CN V on each side
Motor root: smaller, medial part
Sensory root: larger, lateral part
Groove between PONS & MO ( M-L )
CN VI, VII, VIII
1 Cerebral peduncle
-
8/14/2019 BRAINSTEM-Lec by Emma
26/51
1.Cerebral peduncle
2.Basilar groove
3.Olive
4.Pyramid 5.Trigeminal nerve
6.Abducent nerve
-
8/14/2019 BRAINSTEM-Lec by Emma
27/51
POSTERIOR SURFACE:
Limited laterally by SCP
MEDIAN SULCUS- divides pons symmetrically MEDIAL EMINENCE-
Bounded by sulcus limitans
Lateral to sulcus
FACIAL COLLICULUS Slight expansion on inferior end of medial eminence
SUBSTANTIA FERRUGINEA
Bluish gray in superior part of sulcus limitans
AREA VESTIBULI
Lateral to sulcus limitans
Underlying vestibular nuclei
-
8/14/2019 BRAINSTEM-Lec by Emma
28/51
1.Substantia ferruginea
2.Facial colliculus
3.Striae medullares
4.Vestibular area 5.Hypoglossal triangle
6.Vagal triangle
7.Calamus scriptorius
-
8/14/2019 BRAINSTEM-Lec by Emma
29/51
INTERNAL STRUCTURE OF PONS:Divided into:
TEGMENTUM- posterior part BASAL PART- anterior part TRAPEZOID BODY- divides tegmentum & basal part
TRANSVERSE SECTION THROUGH CAUDAL
PART:Medial LemniscusFacial NucleusNucleus of abducent nerve
Facial colliculusMedial longitudinal fasciculusMedial vestibular nucleusPosterior & anterior cochlear nuclei
Spinal nucleus of CN V
-
8/14/2019 BRAINSTEM-Lec by Emma
30/51
TRAPEZOID BODY Fibers derived from cochlear nuclei & nuclei of trapezoid
body
BASILAR PART OF PONS:
Contains small masses of nerve cells: PONTINE
NUCLEICORTICOPONTINE FIBERS of crus cerebri
terminate in pontine nuclei
TRANSVERSE FIBERS enter middle cerebellar
peduncle
-
8/14/2019 BRAINSTEM-Lec by Emma
31/51
TRANSVERSE SECTION THROUGH
CRANIAL PART
Motor nucleus of trigeminal nerve
Principal sensory nucleus of trigeminal nerve
Superior cerebellar peduncleAnterior cerebellar tract
Trapezoid body
-
8/14/2019 BRAINSTEM-Lec by Emma
32/51
MIDBRAIN
CEREBRAL AQUEDUCTNarrow channel traversing midbrain
Filled with CSF
POSTERIOR SURFACE OF MIDBRAIN:COLLICULI ( Corpora Quadrigemina )
Rounded eminences divided into superior &
inferior pairs by a vertical & transverse groove.
SUPERIOR COLLICULI- centers for visual
reflexes
INFERIOR COLLICULI- lower auditory centers
-
8/14/2019 BRAINSTEM-Lec by Emma
33/51
TROCHLEAR- emerges in the midline below
inferior colliculi
LATERAL ASPECT OF MIDBRAIN:SUPERIOR BRACHIUM
Passes from superior colliculus to lateralgeniculate body & optic tract
INFERIOR BRACHIUM
Connects inferior colliculus to:MEDIAL GENICULATE BODY
-
8/14/2019 BRAINSTEM-Lec by Emma
34/51
ANTERIOR ASPECT OF MIDBRAIN:
INTERPENDICULAR FOSSA
Deep depression in the midline, bound on eachside by:
CRUS CEREBRI
POSTERIOR PERFORATED SUBSTANCEMany small blood vessels that perforate the floor
of the interpendicular fossa
OCCULOMOTOR NERVEemerges from agroove on medial side of crus cerebri & passes
forward in lateral wall of cavernous sinus
-
8/14/2019 BRAINSTEM-Lec by Emma
35/51
INTERNAL STRUCTURE OF MIDBRAIN:Midbrain comprises 2 lateral halves:
CEREBRAL PEDUNCLES, each divided into:CRUS CEREBRI- anterior part &TEGMENTUM- posterior part by:SUBSTANTIA NIGRA- pigmented band of gray
matterCEREBRAL AQUEDUCT- narrow cavity w/c
connects 3rd & 4th ventricle
TECTUM- part of midbrain posterior to cerebralaqueduct & has 4 swellings: 2 SUPERIOR COLLICULI 2 INFERIOR COLLICULI
-
8/14/2019 BRAINSTEM-Lec by Emma
36/51
-
8/14/2019 BRAINSTEM-Lec by Emma
37/51
TRANSVERSE SECTION OF MB AT
LEVEL OF INFERIOR COLLICULI
INFERIOR COLLICULUSTROCHLEAR NUCLEUS
Situated in gray matter close to median plane just
posterior to the: MEDIAL LONGITUDINALFASCICULUS
MESENCEPHALIC NUCLEI OF CN V are lateralto cerebral aqueduct
DECUSSATION OF SUPERIOR CEREBELLARPEDUNCLES
Occupies central part of tegmentum anterior to
cerebral aqueduct
RETICULAR FORMATION
-
8/14/2019 BRAINSTEM-Lec by Emma
38/51
RETICULAR FORMATIONMEDIAL LEMNISCUS
Ascends posterior to substantia nigra
SPINAL & TRIGEMINAL LEMNISCI Situated lateral to medial lemniscus
LATERAL LEMNISCUS Posterior to trigeminal lemniscus
SUBSTANTIA NIGRA Large motor nucleus situated between tegmentum & crus
cerebri Concerned w/ mm tone, connected to Cerebral cortex, SC,
hypothalamus & basal nucleiCRUS CEREBRI
Coticospinal & corticonuclear occupy middle 2/3of crus Frontopontine fibers on lateral part
-
8/14/2019 BRAINSTEM-Lec by Emma
39/51
TRANSVERSE SECTION OF MB AT
LEVEL OF SUPERIOR COLLICULI
SUPERIOR COLLICULUS
LIGHT REFLEX- PRETECTAL NUCLEUS
OCCULOMOTOR NUCLEUS situated in centralgray matter close to median plane, just posteriortoMEDIAL LONGITUDINAL FASCICULUS
MEDIAL, SPINAL & TRIGEMINAL LEMNISCI
Form a curved band posterior to substantia nigra butLATERAL LEMNISCUS does not extend superiorly to
this level
1 Pi l l d
-
8/14/2019 BRAINSTEM-Lec by Emma
40/51
1.Pineal gland
2.superior colliculus
3.Inferior colliculus
4.Trochlear nerve 5.Fourth ventricle
6.Pulvinar of thalamus
7.Superior cerebellar
peduncle
-
8/14/2019 BRAINSTEM-Lec by Emma
41/51
RED NUCLEUS
Rounded mass of gray matter situated between
cerebral aqueduct & substantia nigraRedish hue is due to its vascularity & presence
of iron containing pigment in cytoplasm ot its
neurons.
RETICULAR FORMATION
Situated in tegmentum lateral & posterior to red
nucleus
CRUS CEREBRI Contains identical, important descending tracts:
CORTICOSPINAL, CORTICONUCLEAR,
CORTICOPONTINE fibers
-
8/14/2019 BRAINSTEM-Lec by Emma
42/51
-
8/14/2019 BRAINSTEM-Lec by Emma
43/51
BRAINSTEM STROKE
SYNDROMESTWO GENERAL MANIFESTATIONS
EXPECTED OF A BRAINSTEM STROKE: 1. Contralateral hemiplegia
2. Ipsilateral Cranial Nerve Palsy
Also known as ALTERNATING/ CROSSED
HEMIPLEGIA
-
8/14/2019 BRAINSTEM-Lec by Emma
44/51
WEBERS SYNDROME
MEDIAL BASAL MIDBRAIN
Contralateral Hemiplegia
Ipsilateral CN 3 Palsy( Ipsilateral Ptosis )
-
8/14/2019 BRAINSTEM-Lec by Emma
45/51
BENEDIKTS SYNDROME
TEGMENTUM OF MIDBRAINCONTRALATERAL:
Pain & temperature loss
Joint position loss Ataxia
Chorea
IPSILATERAL:CN 3 palsy
-
8/14/2019 BRAINSTEM-Lec by Emma
46/51
-
8/14/2019 BRAINSTEM-Lec by Emma
47/51
LOCKED IN SYNDROME
BILATERAL PONS
Bilateral Hemiplegia
Bilateral CN Palsy
-
8/14/2019 BRAINSTEM-Lec by Emma
48/51
WALLENBERGS or LATERAL
MEDULLARY SYNDROME
LATERAL MEDULLA
IPSILATERAL:Loss of FACIAL SENSATION
Hemiataxia
Horners syndrome
Nystagmus
dysphagia
CONTRALATERALLoss of pain & temperature
-
8/14/2019 BRAINSTEM-Lec by Emma
49/51
LEFT VS. RIGHT CVALEFT BRAIN FUNCTIONS
Language/Communications
Higher skill
logic
RIGHT BRAIN FUNCTIONS Perception
Imagination
Memory
The arts & music
-
8/14/2019 BRAINSTEM-Lec by Emma
50/51
LEFT VS. RIGHT CVA
LEFT CVA a.k.a : Left hemispheric lesion
Dominant hemispheric lesion or CVA
Right hemiplegic
RIGHT CVA a.k.a :Right hemispheric lesion
Non-dominant Hemispheric lesion or CVA
Left hemiplegic
-
8/14/2019 BRAINSTEM-Lec by Emma
51/51