Download Brain Stem - Brain 101

Nabeel Kouka, MD, DO, MBA
www.brain101.info
Basic
Strucrure of
Brain Stem
1. Roof Plate
2. Tegmentum
3. Basal Portion
Basilar (Basal) Portion
Descending Fibers from Cerebral Cortex
1. Corticospinal Tract
2. Corticobulbar Tract
Pyramidal Tract
3. Corticopontocerebellar Fiber
Corticopontine Fiber
Pons Proper (Ventral Pons)
Pontocerebellar Fiber
Basal Portion
Descending Tracts
Corticospinal Tract
Origin: Cerebral Cortex
Brodmann Area 4 (Primary Motor Area, M I)
Brodmann Area 6 (Premotor Area, PM )
Brodmann Area 3,1,2 (Primary Somesthetic Area, S I)
Brodmann Area 5 (Anterior Portion of Sup. Parietal Lobule)
Corona Radiata
lnternal Capsule, Posterior Limb
Crus Cerebri, Middle Portion
Longitudinal Pontine Fiber
Pyramid - pyramidal decussation
Corticospinal Tract - Lateral and Anterior
Termination: Spinal Gray (Rexed IV-IX)
Basal Portion
Descending Tracts
Corticobulbar Tract
- Corticofugal fibers projecting to, and terminating in,
portions of lower brainstem
- Termination:
1) motor nuclei (upper motor neuron pathway)
hypoglossal, ambiguus, facial motor,
trigeminal motor, abducens, trochlear
and oculomotor nucleus
2) sensory relay nuclei
nuclei gracilis and cuneatus, trigeminal
sensory nucleus, solitary tract nucleus
3) reticular formation (corticoreticular fiber)
Basal Portion
Descending Tracts
Corticobulbar Tract - UMN Pathway
- Corticofugal fibers projecting to cranial motor nuclei
GSE - hypoglossal (XII), abducens (VI),
trochlear (IV) and oculomotor (III) nucleus
SVE - ambiguus (IX, X, XI), facial motor (VII),
trigeminal motor (V) nucleus
- largely bilateral
laryngeal, pharyngeal, palatal and upper facial
muscles of mastication and extraocular muscles
- unilateral
lower facial musculature (facial palsy)
SCM and trapezius (uncrossed) --- spinal accessory
- Pseudobulbar Palsy --- syndrome of bilateral UMN lesion
Basal Portion
Descending Tracts
Corticopontocerebellar Fiber
- Corticofugal fibers projecting to
cerebellar hemisphere
- consists of 2 neuron chain
1. Corticopontine fiber projecting to
pontine nuclei
2. Pontocerebellar fiber
crossed mudline and enter cerebellum
as middle cerebellar peduncle
Roof Plate
Midbrain
Superior Colliculus: vision
Inferior Colliculus: hearing
Closed Medulla
Nucleus Gracilis et Cuneatus:
discriminative touch sensation
cf. Cerebelum: equilibrium
Roof Plate of Hypothetized Chordate Ancestor
A. olfaction
B. vision
C. hearing
D. equilibrium
E. discriminative
touch sensation
1. epithalamus
2. superior colliculus
3. inferior colliculus
4. cerebellum
5. nucleus gracilis
et cuneatus
Tegmentum
Cranial nerve Nuclei
Precerebellar Nuclei
Reticular Formation
Tracts
Ascending Cortical Pathway
Cerebellar Circuits
Descending Tract
Composite Bundle
Cranial Nerves
Columns of
Brain Stem
Motor Column
1. GSE
2. SVE
3. GVE
Sensory Column
4. VA (GVA & SVA)
5. GSA
6. SSA
Components of Cranial Nerves
General Somatic Efferent Nuclei (GSE)
Hypoglossal Nucleus
XII
Abducens Nucleus
VI
Trochlear Nucleus
IV
Oculomotor Nucleus
III
Special Visceral Efferent Nuclei (SVE)
Nucleus Ambiguus
IX, X, XI
Facial Motor Nucleus
VII
Trigeminal Motor Nucleus
V
General Visceral Efferent Nuclei (GVE)
Dorsal Motor Nucleus of Vagus
X
Inferior Salivatory Nucleus
IX
Superior Salivatory Nucleus
VII
Edinger-Westphal Nucleus
III
Motor Nuclei of
Cranial Nerves
1. GSE
III, IV, VI, XII
2. SVE
V, VII,
IX, X, XI
3. GVE
III, VII, IX, X
General Somatic Afferent Nuclei (GSA)
Trigeminal Sensory Nucleus
V, VII, IX, X
Mesencephalic Tract Nucleus
Principal (Main) Sensory Nucleus
Spinal Tract Nucleus
pars oralis
pars interpolaris
pars caudalis
Visceral Afferent Nuclei (VA)
Nucleus Tractus Solitarius
VII, IX, X
General Visceral Afferent (GVA)
Special Visceral Afferent (SVA): Taste
Gustatory Nucleus
Special Somatic Afferent Nuclei (SSA)
Cochlear Nucleus
VIIIc
Dorsal Cochlear Nucleus
Ventral Cochlear Nucleus
Vestibular Nucleus
VIIIv
Medial Vestibular Nucleus
Lateral Vestibular Nucleus
Superior Vestibular Nucleus
Inferior Vestibular Nucleus
Sensory Nuclei of
Cranial Nerves
1. VA
GVA --- IX, X
SVA --- VII, IX, X
2. GSA
V, VII, IX, X
3. SSA
VIIIc, VIIIv
Precerebellar Nuclei
Accessory Cuneate Nucleus
Inferior Olivary Nuclear Complex
Vestibular Nuclus
Red Nucleus
Perihypoglossal Nucleus
Precerebellar Reticular Nuclei
Precerebellar
Nuclei
1. Red Nucleus
2. Vestibular Nucleus
3. Inferior Olivary
Nucleus
4. Perhypoglossal
Nuclei
5. Accessory
Cuneate Nucleus
Reticular
Formation
A. Raphe Nuclei
B. Central
Nuclear Group
C. Lateral
Nuclear Group
D. Precerebellar
Reticular Nuclei
A
B
C
D
Central Nuclear Group of Reticular Formation
Gigantocellular Reticular Nucleus
Caudal Reticulopontine Nucleus
Oral Reticulopontine Nucleus
Subcuneiform Nucleus
Cuneiform Nucleus
Lateral Nuclear Group of Reticular Formation
Central Nucleus of Medulla Oblongata
Superficial Ventrolateral Reticular Area
Parvicellular Reticular Nucleus
Parabrachial Nucleus
Pedunculopontine Nucleus
Raphe Nuclei - Serotonergic Neuron
Nucleus Raphe Obscrus, B2
Nucleus Raphe Pallidus, B1
Nucleus Raphe Magnus, B3
Pontine Raphe Nucleus, B5
Median Raphe or Superior Central Nucleus, B6, B8
Dorsal Raphe Nucleus, B7
Nucleus Linealis
Norepinephrinergic & Dopaminergic Neuron
Norepinephrinergic Neuron
Nucleus Locus Ceruleus, A6
Dopaminergic Neuron
Retrorubral Area, A8
Ventral Tegmental Area, A10
Substantia Nigra, Pars Compacta, A9
Ascending Cortical Pathway
Posterior White Column-Medial Lemniscal Pathway
medial lemniscus
Spinothalamic and Spinoreticular Tract
spinal lemniscus
Ventral and Dorsal Trigeminothalamic Tract
trigeminal lemniscus
Auditory Pathway: lateral lemniscus
Taste (Gustatory) Pathway: central tegmental tract
Vestibular Pathway: medial lemniscus
Ascending Cortical System
General Sensation
Brain Stem Pathways for General Sensation
Touch & Proprioception from body
Posterior White Colum-Medial Lemniscal Pathway
Pain & Temperature from body
Spinothalamic Tract
cf. Spinoreticular or Spinoreticulothalamic Tract
General Sensation from Face
Trigeminothalamic Tracts
Posterior White Column - medial Lemniscal Pathway
& Spinothalamic Tract
Posterior White Colum-Medial Lemniscal Pathway
Modality: Discriminative Touch Sensation (include Vibration) and
Conscious Proprioception (Position Sensation, Kinesthesia)
from body
Receptor: Most receptors except free nerve endings
Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion)
Posterior White Column
2nd Neuron: Dorsal Column Nuclei (Nucleus Gracilis et Cuneatus)
Internal Arcuate Fiber - Lemniscal Decussation - Medial Lemniscus
3rd Neuron: Thalamus (VPLc)
Internal Capsule ----- Corona Radiata
Termination: Primary Somesthetic Area (S I)
D
Posterior White ColumnMedial Lemniscal Pathway
DRG: Dorsal Root Ganglion
1. Posterior White Column
A. Nucleus gracilis
B. Nucleus cuneatus
2. Medial Lemniscus
3. Corona Radiata
DRG
C. Thalamus (VPLc)
D. Cerebral Cortex (S I)
Spinothalamic Tract
Modality: Pain & Temperature Sensation, Light Touch
from body
Receptor: Free Nerve Ending
Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion)
2nd Neuron: Dorsal Horn (Lamina I, IV, V)
Anterior White Commissure
Spinothalamic Tract (Spinal Lemniscus)
3rd Neuron: Thalamus (VPLc & CL)
Internal Capsule ----- Corona Radiata
Termination: Primary Somesthetic Area (S I)
Spinoreticulothalamic Tract
(Paleospinothalamic Tract)
Modality: Pain & Temperature Sensation, Light Touch
from body
Receptor: Free Nerve Ending
Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion)
2nd Neuron: Dorsal Horn (Lamina I, IV, V)
Anterior White Commissure
Spinothalamic Tract (Spinal Lemniscus)
3rd Neuron: Reticular Formation
4rd Neuron: Thalamus (CL, Sm, POm)
Internal Capsule ----- Corona Radiata
Termination: Diffuse Cerebral Cotex
Spinothalamic Tract
D
(Neospinothalamic Tract)
Spinoreticular Tract
(Paleospinothalamic Tract)
DRG: Dorsal Root Ganglion
A. Posterior (dorsal) horn
1. Spinothalamic tract
B. Reticular formation
DRG
2. Spinoreticular tract
C. Thalamus (VPLc, CL)
3. Corona Radiata
D. Cerebral Cortex (S I)
Trigeminothalamic Tract
Modality: General Sensation from face
Receptor: Most receptors in the face
Ist Neuron: Trigeminal (Semilunar) Ganglia
2nd Neuron: Trigeminal Sensory Nucleus
pain & temperature ---- pars caudalis of
spinal tract nucleus of V
Ventral and Dorsal Trigeminothalamic Tract
3rd Neuron: Thalamus (VPM)
Internal Capsule ----- Corona Radiata
Termination: Primary Somesthetic Area (S I)
A. trigeminal ganglion
B. trigeminal sensory
nucleus
C. thalamus (VPM)
D. cerebral cortex
(S I)
1. spinal tract of
trigeminal nerve
2. ventral
trigeminothalamic tract
3. dorsal
trigeminothalamic tract
4. corona radiata
V. trigeminal nerve
Trigeminothalamic Tract
Ascending Cortical System
Special Sensation
Brain Stem Pathways for Special Sensation
Gustatory Sensation (Taste, SVA)
----- Taste Pathway
Auditory Sensation (Hearing, SSA)
----- Auditory Pathway
Vestibular Sensation (Equilibrium, SSA)
----- Vestibular Pathway
Auditory Pathway
Modality: Auditory Sensation (Hearing)
Receptor: Organ of Coti of Cochlear Duct
Cranial Nerve: VIIIc
1st Neuron: Spiral Ganglion
2nd Neuron: Cochlear Nucleus, Ventral & Dorsal
dorsal, intermediate and ventral acoustic striae
trapezoid body
lateral lemniscus
3rd Neuron: Inferior Colliculus
brachium of inferior colliculus
4th Neuron: Medial Geniculate Nucleus (MG)
auditory radiation
Termination: Primary Auditory Area (A I)
Brodmann area 31, 32
A. spiral ganglion
B. dorsal and ventral
cochlear nucleus
C. inferior colliculus
D. medial geniculate
nucleus
E. Primary auditory area
F. superior olivary nucleus
G. nucleus of
lateral lemniscus
1. acoustic striae &
trapezoid body
2. lateral lemniscus
3. brachium of inferior
colliculus
4. auditory radiation
5. commissure of
inferior colliculus
VIIIc. cochlear division
Auditory Pathways
Auditory Pathway
A. spiral ganglion
B. dorsal cochlear nucleus
C. ventral cochlear nucleus
D. superior olivary nucleus
1. dorsal acoustic striae
2. intermediate acoustic
striae
3. ventral acoustic striae
4. efferent cochlear bundle
5. trapezoid body
6. lateral lemniscus
Vestibular Pathway
Modality: Equilibrium Sensation
Receptor: Macula & Crista Ampullaris
Cranial Nerve: VIIIv
Ist Neuron: Vestibular Ganglion
2nd Neuron: Vestibular Nucleus
vestibulothalamic fiber (medial lemniscus)
3rd Neuron: Thalamus (VPLo, VPI?)
Internal Capsule ----- Corona Radiata
Termination: Primary Vestibular Area
----- Primary Somesthetic Area
(Brodmann area 3a, 2v )
Vestibular
Pathway
1. Vestibulocerebellar Tract
2. Vestibulospinal Tract
3. Vestibulothalamic Tract
4. Medial Longitudinal
fasciculus (MLF)
- ascending portion
- descending portion
- interstitiospinal tract
Taste (Gustatory) Pathway
Modality: Taste Sensation
Receptor: Taste Bud
Cranial Nerve: VII, IX, X
Ist Neuron: Geniculate Ganglion (VII)
Inferior Ganglion (IX, X)
2nd Neuron: Nucleus Tractus Solitarius
(Gustatory Nucleus)
solitariothalamic fiber (central tegmental tract)
3rd Neuron: Thalamus (VPMpc)
Internal Capsule ----- Corona Radiata
Termination: Gustatory Area
Brodmann area 43 & parainsular cortex
A. nucleus tractus
solitarius
(gustatory nucleus)
B. thalamus (VPMpc)
C. Brodmann area 43
D. parainsular cortex
E. parabrachial
nucleus
1. solitariothalamic
fiber (central
tegmental tract)
2. corona radiata
VII. facial nerve
IX. glossopharyngeal
nerve
X. vagus nerve
Taste Pathways
Cerebellar Circuits
Superior, Middle and Inferior Cerebellar Peduncle
Vestibulocerebellum - Vestibular Nucleus
Spinocerebellum - Red Nucleus and Spinal Cord
Pontocerebellum - Cerebral Cortex and Pontine Nuclei
Inferior Olivary Nuclear Complex
Afferent Connections
of Cerebellum
Inferior Cerebellar Peduncle
1. posterior spinocerebellar tract
2. cuneocerebellar tract
3. vestibulocerebellar tract
Middle cerebellar Peduncle
- corticopontocerebellar
pathway
Superior Cerebellar Peduncle
- anterior spinocerebellar tract
Efferent Connections
of Cerebellum
Superior Cerebellar Peduncle
1. dentatothalamic fiber
2. interpositorubral fiber
3. ascending portion of
uncinate fasciculus of Russell
Inferior Cerebellar Peduncle
1. direct fastigiovestibular fiber
2. descending portion of
uncinate fasciculus of Russell
Connections of
Inferior Olivary
Nuclear Complex
1. Olivocerebellar Tract
2. Cortico-olivary Tract
3. Rubro-olivary Tract
4. Vestibulo-olivary Tract
5. Spino-olivary Tract
Descending Tracts
Rubrospinal Tract
Tectospinal tract
Vestibulospinal Tract
Reticulospinal Tract
pontine and medullary
Descending Autonomic Pathway
Brain Stem
Descending Tracts
Descending Tracts from Brain Stem
Dorsolateral (Motor) Pathway
Rubrospinal Tract
Ventromedial (Motor) Pathway
Tectospinal Tract
Vestibulospinal Tract
MLF (Medial Longitudinal Fasciculus)
- interstitiospinal tract
Sensory Modulation pathways
Raphespinal & Cerulospinal Pathways
Descending Autonomic Pathways
Composite Bundle
Medial Longitudinal Fasciculus (MLF)
Dorsal Longitudinal Fasciculus (DLF)
Central Tegmental Tract
Components of Medial Longitudinal Fasciculus (MLF)
Descending Components
Medial Vestibulospinal Tract
from medial and inferior vestibular nucleus
Interstitiospinal Tract
from interstitial nucleus of Cajal
Ascending Components
Efferents from Medial Vestibular Nucleus
contralateral III, IV, interstitial nucleus
bilateral VI nucleus
Efferents from Superior Vestibular Nucleus
ipsilateral III, IV, interstitial nucleus
Components of Dorsal Longitudinal Fasciculus
(DLF, fasciculus of Schütz)
Ascending Components
solitariohypothalamic fiber
(visceral afferent fiber)
ascending serotonergic fiber
Descending Component
descending fibers from hypothalamus
to periaqueductal gray and
dorsal tegmental nucleus
Components of Central Tegmental Tract
Ascending Components
reticulothalamic fiber
solitariothalamic fiber
(secondary taste fiber)
Descending Component
rubro-olivary tract
Spinomedullary Transition
(Level of Pyramidal Decussation)
Roof Plate - fasciculus gracilis and fasciculus cuneatus
Tegmentum
Cranial and Spinal Nerve Nuclei
Supraspinal Nucleus
Spinal Nucleus of Trigeminal Nerve, Pars Caudalis
Reticular Formation
Central Nucleus of Medulla Oblongata
(Ventral Reticular Nucleus)
Unclassified Nuclei
Retroambiguus Nucleus
Tracts
Spinal Tracts of Trigeminal Nerve
Basal Part - Pyramid, Pyramidal Decussation
Spinomedullary Transition
(Level of Pyramidal Decussation)
Cranial & Spinal N. Nuclei
1. Supraspinal Nucleus
2. Spinal Accessory Nucleus
Cranial & Spinal Nerve
XI. Accessory Nucleus
C1. motor root of
1st cervical nerve
Lower Medulla (Level of Lemniscal Decussation)
Roof Plate - nucleus gracilis and nucleus cuneatus
Tegmentum
Cranial and Spinal Nerve Nuclei
Hypoglossal Nucleus, Ambiguus Nucleus
Solitary Tract Nucleus, Dorsal Motor Nucleus of X
Reticular Formation
Lateral Reticular Nucleus
Precerebellar Nuclei
Inferior Olivary Nuclear Complex
Tracts
Ventral Trigeminothalamic Tract
Internal Arcuate Fiber, Lemniscal Decussation
Basal Part - Pyramid, Pyramidal Decussation
Lower Medulla
(Level of Lemniscal
Decussation)
Roof Plate
A. Nucleus Gracilis
B. Nucleus Cuneatus
Cranial Nerve Nuclei
1. Hypoglossal Nucleus
2. Nucleus Ambiguus
3. Dorsal Motor Nucleus of X
4. Nucleus Tractus Solitarius
5. Spinal Tract Nucleus of
Trigeminal Nerve
Lower Medulla
(Level of Lemniscal
Decussation)
Precerebellar Nucleus
1. Inferior Olivary Nuclear Complex
1a. Principal Inferior
Olivary Nucleus
1b. Medial Accessory
Olivary Nucleus
1c. Dorsal Accessory
Olivary Nucleus
2. Nucleus Intercalatus
3. Nucleus Conterminalis
4. Arcuate Nucleus
Lower Medulla
(Level of Lemniscal
Decussation)
Reticular Formation
1. Lateral Reticular Nucleus
2. Central Nucleus of
Medulla Oblongata
2d. subnucleus dorsalis
2v. subnucleus ventralis
Clinical Syndromes
of Lower Medulla
A. Hypoglossal
Alternating Hemiplegia
B. Avelis Syndrome
C. Jackson Syndrome
D. Tapia Syndrome
1. pyramidal tract
2. hypoglossal nerve
3. spinothalamic tract
4. nucleus ambiguus
Hypoglossal
Palsy
Lower Motor
Neuron
Syndrome
Deviation of Tongue to affected side
Atrophy of Tongue Muscles
Open Medulla (Mid-olivary Level)
Tegmentum
Cranial Nerve Nuclei
Medial Vestibular Nucleus
Spinal Tract Nucleus of V, pars interpolaris
Precerebellar Nuclei
Accessory Cuneate Nucleus
Nucleus of Roller, Nucleus Interfascicularis Hypoglossi
Reticular Formation
Lateral Reticular Nucleus, subtrigeminal portion
Unclassified Nuclei
Area Postrema
Tracts: Inferior Cerebellar Peduncle, DLF
Basal Part - Pyramid
Open Medulla
(Mid-olivary Level)
Cranial Nerve Nuclei
1. Hypoglossal Nucleus
2. Nucleus Ambiguus
3. Dorsal Motor Nucleus of X
4. Nucleus Tractus Solitarius
5. Spinal Tract Nucleus,
pars interpolaris
6. Medial Vestibular Nucleus
Open Medulla
(Mid-olivary Level)
Precerebellar Nucleus
1. Accessory Cuneate Nucleus
2. Inferior Olivary Nuclear Complex
2a. Principal Inferior Olivary Nuc.
2b. Medial Accessory Olivary Nuc.
2c. Dorsal Accessory Olivary Nuc.
3. Nucleus Intercalatus
4. Nucleus of Roller
5. Nucleus Interfascicularis
Hypoglossi
6. Nucleus Conterminalis
Open Medulla (Mid-olivary Level)
XII. Hypoglossal Nerve
1. Hypoglossal Nucleus
X. Vagus Nerve
2. Nucleus Ambiguus
3. Dorsal Motor Nucleus of X
4. Nucleus Tractus Solitarius
5. Spinal Tract Nucleus of V
Clinical Syndromes
of Open Medulla
A. Dejerine’s Syndrome
1. pyramidal tract
2. hypoglossal nerve
3. medial lemniscus
B. Wallenberg Syndrome
4. spinothalamic tract
5. spinal tract of trigeminal nerve
6. nucleus ambiguus
7. descending autonomic
pathway
Wallenberg Syndrome
Spinothalamic tract
- contralateral loss of pain and
temperature sensation at the body
Spinal tract of trigeminal nerve
- ipsilateral loss of pain and
temperature sensation at the face
Nucleus ambiguus
- dysphageia, dysarthria, hoarseness
Descending autonomic pathway
- Horner’s syndrome
(meiosis, ptosis, anhydrosis)
Open Medulla (Upper Level of Medulla)
Tegmentum
Cranial Nerve Nuclei
Inferior Vestibular Nucleus
Dorsal Cochlear Nucleus
Precerebellar Nuclei
Nucleus Prepositus Hypoglossi
Reticular Formation
Gigantocellular Reticular Nucleus
Paragigantocellular Reticular Nucleus
Parvocellular Reticular Nucleus
Raphe Nuclei
Unclassified Nuclei
retrofacial, supravestibular nucleus, nucleus interpositus
Tracts: stria medullaris of 4th ventricle
Basal Part - Pyramid
Open Medulla
(Upper Level of Medulla)
Cranial Nerve Nuclei
1. Nucleus Ambiguus
2. Nucleus Tractus Solitarius
3. Spinal Tract Nucleus,
pars oralis
4. Medial Vestibular Nucleus
5. Inferior Vestibular Nucleus
6. Dorsal Cochlear Nucleus
Open Medulla
(Upper Level of Medulla)
Precerebellar Nucleus
1. Inferior Olivary Nuclear Complex
2a. Principal Inferior Olivary Nuc.
2b. Medial Accessory Olivary Nuc.
2c. Dorsal Accessory Olivary Nuc.
2. Nucleus Prepositus Hypoglossi
3. Pontobulbar Body
4. Arcuate Nucleus
5. Medial Vestibular Nucleus
6. Inferior Vestibular Nucleus
Open Medulla
(Upper Level of Medulla)
Reticular Formation
1. Paramedian reticular Nucleus
2. Gigantocellular Reticular Nucleus
3. paragigantocellular
Reticular Nucleus
4. Parvocellular Reticular Nucleus
5. Nucleus raphe Obscrus (B2)
6. Nucleus Raphe Pallidus (B1)
7. Nucleus Raphe Magnus (B3)
Unclassifiied Nuclei
A. Nucleus Retrofacialis
B. Supravestibular Nucleus
C. Nucleus Interpositus
Open Medulla (Upper Level of Medulla)
IX. glossopharyngeal
Nerve
1. Nucleus Ambiguus
2. Inferior Salivatory Nucleus
3. Nucleus Tractus Solitarius
4. Spinal Tract Nucleus of V
Pontomedullary Junction
Tegmentum
Cranial Nerve Nuclei
Facial Motor Nucleus
Ventral Cochlear Nucleus
Precerebellar Nuclei
Reticular Formation
Unclassified Nuclei
nucleus ovalis
Tracts
Basal Part - Pyramid
Cranial Nerve - Vestibulocochlear Nerve (VIII)
Facial Nerve (VII)
Pontomedullary
Junction
Cranial Nerve Nuclei
1. Facial Motor Nucleus
2. Nucleus Ambiguus
3. Spinal Tract Nucleus,
pars oralis
4. Medial Vestibular Nucleus
5. Inferior Vestibular Nucleus
6. Ventral Cochlear Nucleus
Pontomedullary
Junction
Precerebellar Nucleus
1. Principal Inferior
Olivary Nucleus
2. Nucleus Prepositus
Hypoglossi
3. Pontobulbar Body
4. Arcuate Nucleus
5. Medial Vestibular Nucleus
6. Inferior Vestibular Nucleus
Pontomedullary
Junction
Reticular Formation
1. Paramedian reticular Nucleus
2. Gigantocellular
Reticular Nucleus
3. paragigantocellular
Reticular Nucleus
4. Parvocellular Reticular Nucleus
7. Nucleus Raphe Magnus (B3)
Unclassifiied Nuclei
A. Nucleus Interpositus
B. Nucleus Ovalis
Lower Pons (Level of Abducens Nucleus)
Tegmentum
Cranial Nerve Nuclei
Abducens Nucleus, Main Sensory Nucleus of V
Nuclei of Auditory Pathway
Superior Olivary Nuclear Complex
Reticular Formation
Caudal Pontine Reticular & Subceruleus Nucleus
Tracts
Trapezoid Body, lateral Lemniscus,
Central tegmental Tract
Basal Part: Pons Proper:
Pontine Nuclei,
Transverse Pontine Fiber,
Longitudinal Pontine Fiber (Pyramidal Tract)
Lower Pons (Level of Abducens Nucleus)
Cranial Nerve Nuclei
1. Abducens Nucleus
2. Main Sensory Nucleus of V
3. Lateral vestibular Nucleus
4. Superior Vestibular Nucleus
Auditory Relay Nuclei
A. Superior Olivary Nucleus
B. Nucleus of Trapezoid body
Lower Pons (Level of Abducens Nucleus)
Reticular Formation
1. Gigantocellular
Reticular Nucleus
2. Caudal Pontine
Reticular Nucleus
3. Parvocellular
Reticular Nucleus
4. Nucleus Subceruleus
VII. Facial Nerve
1. Facial Motor Nucleus
2. Superior Salivatory Nucleus
3. Nucleus Tractus Solitarius
4. Spinal Tract Nucleus of V
VI. Abducens Nerve
5. Abducens Nucleus
A. Facial Palsy
B. A + decreased salivation
C. A + B + hyperacusis
D. A + B + C + decrased
lacrimal secretion
E. Central Type Facial Palsy
1. Facial Motor Nucleus
2. Superior Salivatory Nucleus
3. Solitary Nucleus
4. Spinal Tract Nucleus of
Trigeminal Nerve
Facial Palsy
(Bell’s Palsy)
Lower Motor
Neuron
Syndrome
Triple W Sign - Wrinkle, Wink, Whistle
Facial Palsy (Bell’s Palsy)
Right facial paralysis
Central Type
Facial Palsy
Upper Motor
Neuron
Syndrome
facial motor nucleus neurons
supplying forehead muscle
Bilateral Corticobulbar Tract
Abducens
Palsy
Lower Motor
Neuron
Syndrome
Lateral Gaze Paralysis
Upper Pons (Level of Trigeminal Motor Nucleus)
Tegmentum
Cranial Nerve Nuclei
Trigeminal Motor Nucleus,
Mesencephalic Tract Nucleus of Trigeminal Nerve
Nuclei of Auditory Pathway
Nucleus of Lateral Lemniscus
Reticular Formation
Reticular Tegmental Nucleus
Unclassified Nucleus
Pontine Central Gray: Ch6
Tracts
Trigeminal Nerve Fiber
Basal Part: Pons Proper
Upper Pons (Level of Trigeminal Motor Nucleus)
Cranial Nerve Nuclei
1. Trigeminal Motor Nucleus
2. Main Sensory Nucleus of V
3. Mesencephalic Tract
Nucleus of V
4. Superior Vestibular Nucleus
Auditory Relay Nuclei
A. Nucleus of Lateral Lemniscus
Upper Pons (Level of Trigeminal Motor Nucleus)
Reticular Formation
1. Caudal Pontine
Reticular Nucleus
2. Nucleus Subceruleus
3. Reticular Tegemntal
Nucleus of Bekhterew
(Nucleus Papilloformis of
Olszewski and Baxter)
Clinical Syndromes
of Pons
A. Millard-Gubler Syndrome
B. Raymond Syndrome
C. Foville Syndrome
D. Raymond-Cestan Syndrome
E. Marie-Poix Syndrome
1. pyramidal tract
2. MLF
3. medial lemniscus
4. spinothalamic tract
5. trigeminal motor nucleus
6. main sensory nucleus of V
7. spinal tract of trigeminal nerve
8. middle cerebellar peduncle
Trigeminal Neuralgia
(tic douloureux)
- excruciating episodic pain
in the area supplied by
trigeminal nerve, especially
second and third division
- trigger point
- intense pain makes the
patient grimace (tic)
- antiepileptic drug (phenytoin,
carbamazepine) is effective
- surgical treatment
Lower Midbrain (Level of Inferior Colliculus)
Roof Plate - Tectum: Inferior Colliculus
Tegmentum
Cranial Nerve Nuclei
Trochlear Nucleus
Reticular Formation
Cuneiform, Pedunculopontine, Parabrachial
and Median Raphe (Superior Central) Nucleus
Unclassified Nuclei
Periaqueductal Gray
Tracts
Decussation of Superior Cerebellar Peduncle
Basal Part - Crus Cerebri, Pons Proper
Lower Midbrain
(Level of Inferior
Colliculus)
Roof Plate
A. Inferior Colliculus
Cranial Nerve Nuclei
1. Mesencephalic Tract
Nucleus of
Trigeminal Nerve
2. Trochlear Nucleus
Lower Midbrain
(Level of Inferior
Colliculus)
Reticular Formation
1. Cuneiform Nucleus
2. Pedunculopontine Nucleus
3. Nucleus Locus ceruleus
4. Parabrachial Nucleus
5. Dorsal Raphe Nucleus
6. Median Raphe Nucleus
5
6
Unclassified Nuclei
A. Periaqueductal Gray
B. Dorsal Tegmental Nucleus
of Gudden
C. Interpeduncular Nucleus
D. Parabigeminal Nucleus
C
Upper Midbrain (Level of Superior Colliculus)
Roof Plate - Tectum: Superior Colliculus
Tegmentum
Cranial Nerve Nuclei
Oculomotor and Edinger-Westphal Nucleus
Reticular Formation - Subcuneiform Nucleus
Precerebellar Nuclei
Red Nucleus
Unclassified Nuclei
Substantia Nigra, Paranigral, Paralemniscal Nucleus
Ventral Tegmental Area (VTA)
Tracts
Brachium of Inferior Colliculus
Basal Part - Crus Cerebri
Upper Midbrain
(Level of Superior
Colliculus)
Roof Plate
A. Superior Colliculus
Precerebellar Nucleus
B. Red Nucleus
Cranial Nerve Nuclei
1. Mesencephalic Tract
Nucleus of V
2. Oculomotor Nucleus
3. Edinger-Westphal Nucleus
Upper Midbrain
(Level of Superior
Colliculus)
Reticular Formation
A. Cuneiform Nucleus
B. Subcuneiform Nucleus
Unclassified Nuclei
1. Periaqueductal Gray
2. Paralemniscal Nucleus
3. Substantia Nigra
3a. Pars Compacta
3b. Pars Reticulata
4. Paranigral Nucleus
5. Ventral Tegmental Area
Clinical Syndromes
of Upper Midbrain
A. Weber Syndrome
B. Foix Syndrome
C. Benedikt’s Syndrome
D. Claude Syndrome
E. Parinaud’s Syndrome
1. pyramidal tract
2. superior cerebellar peduncle
3. red nucleus
4. medial lemniscus
5. superior colliculus
6. cerebral aqueduct
7. MLF
8. oculomotor nucleus
Weber Syndrome
Pyramidal tract
- contralateral UMN syndrome
at the body and lower face
(contralateral hemiparesis)
Oculomotor Nerve
- ipsilateral ocular palsy
- external strabismus
- mydriasis
- loss of accommodation
- normal consensual light reflex