Brain & Cranial Nerves

1. Brdih- Mania Nes

nn, la.

2. > Planes of the Human Brain

Sagittal
plane

Horizontal
plane

Cross
section

6. “neural plate a

notochord

Y

epidermis

Ventral

8. Forebrain Midbrain Hindbrain

Diencephalon M ephalon

Spinal
cord

9. Midbrain

Forebrain —f >
Hindbrain

Forebrain
Spinal cord ——
3 weeks

Midbrain

Forebrain

1 Hindbrain
\

Midbrain Hindbrain

Î

cranial

nerves

7 weeks

Forebrain
|

A

F—-Cerebellum
Medulla

Midbrain
(hidden)

7

12. Mdbrain ty

13. Longitudinal

15. Precentral Gyrus

Lateral Sulcus

Temporal Lobe

divide each
five anatomically Pons
distinct lobes
Medulla Oblongata
Icus- posterior

central Sulcus

Postcentral Gyrus

Parietal Lobe

ital Lobe

Cerebellum

20. Middle 3 |
Meningeal PA Superior

Artery «+ À Sagittal

Sinus

Occipital
Pole

21. Dural
Layers

22. Meningeal

25. Arachnoid

PIA
MATER

(meningies |
that adhered |
to brain)

26. >

Ant. E
Crista

Cranial | =
Fossa 7 AL

’ / Middle

Cranial
Fossa

y * Post.
No Cranial
> Fossa.
. Posterior
. Transverse
Cranium 01 Septum

27. Dura mater
Arachnoid

30. Spinal

Spinal
column

33. Slide 9 Cerebellum and Medulla

Cerebellum

Separation
artifact

S

Nee
y Pia mater
Fe

=

Medulla

34. Meninges
dural sinus

LE. TT
dura mater —,
arachnoid ~ =

pia mater —

subarachnoid space

e dura in the cranial cavity consist of two layer
periosteal layer-

36. | | mM
|

37. Partitions formed by the Dura Mater

falx cerebri

tentorium

falx
cerebelli
Note the dural sinuses which appear as blue
vessels inside the dura mater.

Modified from: Prentice Hall, Martini/Timmons 1997

41. Falx cerebri

43. J. Cavernous

K. Superior Sagittal

Dural Venous Sinuses.
Sphenoparietal
Intercavernous
Sigmoid
Occipital
Confluence
Basilar
Transverse
Superior Petrosal
Inferior Petrosal
Cavernous

Superior

44. The Dural Venous Sinuses

Sigmoid Sinus

Superior Petrosal Sinus
Transverse Sinus
Straight Sinus

Inferior Sagittal sinus

Dural Venous Sinuses: Lateral
View

A. Superior Sagittal
Sinus

B. Great Cerebral Vein

C. Ophthalmic Veins

D. Facial Vein
Cavernous Sinus

F. Inferior Petrosal
Sinus

G. Jugular Vein

45. Third
ventricle

Cerebral
aqueduct

Fourth
ventricle

ventricles

46. interventricular
foramen

to central canal -
inal cord

_ lateral
7 ventricle

cerebral

aqueduct

(aqueduct of
5)

ventricle

47. » Ventricular System of the Brain

48. Central canal

# Ependymal cells

50. Choroid plexus

51. e 2 O
Ventricle y AN) Ependymal:

cells

52. Circulation of
Cerebrospinal Fluid

subarachnoid blood sinus (blue)

space (green) arachnoid
E granulations

choroid plexus
in ventricles

> apertures
in 4th ventricle lead

to subaracnoid
space

Modified from: Prentice Kall, Martini/Timmons 1997

53. Arachnoid Granulations (Villi)

61. > Cortical Control of Movement

Movement of Muscles

Supplementary Primary motor
motor area cortex

Premotor Parietal lobe

>
‚spac&and

location of limbs,

Prefrontal
cortex
Temporal lobe Occipital lobe

62. Primary sensory, motor, and association areas of the cerebral cortex

Primary Motor Primary 0

63. input

68. Copniight © Tin McGraw-Hill Cormperses, bre. Permission unsre ha e diseler

Cerebral Cortex and Associated Body
Regions

Tongue
Jaw

Pharyny

74. ith the
ited in

75. Caudale nucleus (nucleus caudatus)|

76. Basal Ganglia

77. AS

Marais

MR

ps

78. Figure AB-19: Basal Ganglia Pathways

—

(Pre-trontal)
‚orte;
Pre-

_— Thalamus

Caudate ~
_ Subthalamic

— Nucleus

“> Substantia Nigra

Pallidus
Neostriatum = Caudate + Putamen

Striatum = Caudate + Putamen
+ Globus Pallidus

Diagram colors are consistent with Figure AB-18.

81. Brain SUBCORTICAL
STRUCTURES

BASAL GANGLIA
« Striatum
- Caudate
- Putamen
« Globus Pallidus

THALAMUS

Note: Collectively the
putamen & globus
pallidus are referred to as
the lentiform or lenticular
nucleus.
A lesion to the PLIC will produce both contralateral sensory and motor deficits.
The descending motor paths pass through it and the ascending sensory,
thalamocortical fibers ascend in it. However, aphasias will not be involved.

POSTERIOR
LIMB INTERNAL
CAPSULE (PLIC)

82. rebral cortex
(i.e, motor)

Basal ganglia Cerebellum

Motor neurons
and interneurons

90. Figure F-8: Inferior Olive & Purkinje Cells

( Cerebellum }

\
\ =;

| Se
Granule cells | | Purkinje
pa,

a >.

<< Inferior Olive >

The inferior olive inputs sensory information to the
and the Purkinje cells communicate the output.

91. Frontal-motor
cortex

parietal

¡Midline

Cerebellar cortex

Inferior
olive

Vestibular
nucleus:

Spinal

cord

Pontine
nucle

Vestibular

Inferior olive —

93. Lobules of Ve Brainstem Anatomy

Lingula A Midbrain

Central lobule Pons

Culmen > Medulla

Declive Cerebral aquaduct
Folium Fourth

Tuber Pi fissure
Pyramis 3 Posterolateral fissure
Uvula

Nodulus

94. Landmarks and functional divisions of the cerebellum

Primary

ENS

E

Ponto-
cerebellum

Made

Spino-
cerebellum

: … Vestibulo-cerebellum

96. LEVEL OF THE MIDBRAIN CROSS SECTION

Cross section through the
superior colliculus, aqueduct,
Anterior body of the midbrain & CN3.

97. Posterior
Cut, removed and +

rotated 90 degrees.

Superior Colliculus Level
of the Midbrain

98. Posterio
as Posterior
D Cut, removed and Y
ge rotated 90 degrees.
Anterior

Contralateral
upper motor

neuron

symptoms to the

face & body: Cerebral Peduncle
Babinski Sign White matter,

‘ heavily myelinated.

2 ie de Descending motor

* Spasticity paths: corticospinal

» Hyperreflexia & corticobulbar

‘ ue tracts. Lesion would
(except disuse) give rise to contra-

lateral upper motor
neuron signs.

99. Posterior un

Cut, removed and
rotated 90 degrees.

Anterior

Substantia Nigra

Pigmented,
neuronal
population with
dopaminergic
neurons.
Degenerates
bilaterally in
Parkinson's
Disease.

100. Posterior un

Cut, removed and
rotated 90 degrees.

nterior
Red Nucleus

Heavily
vascularized.
Gives rise to a
crossed pathway
(rubrospinal tract)
that assists the
corticospinal
tract.

101. Anterior

Contralateral Symptoms
to the upper & lower

extremities if lesion is
complete:

+ Loss of position sense
+ Loss of vibratory sense
+ Decreased fine tactile

Cut, removed and
rotated 90 degrees.

Medial Lemniscus
Information from the
post column
pathways of the
contralateral spinal
cord.

102. Anterior

Contralateral Symptoms
to the upper & lower
extremities:

+ Loss of pain (pinprick)

+ Loss of temperature

+ Loss of light touch

Cut, removed and
rotated 90 degrees.

Spinothalamic Tract
Pain, temp, light
touch from the
contralateral upper
& lower extremities.

103. { Posterior
Cut, removed and eS 4 4

rotated 90 degrees. E

Anterior

Contralateral Symptoms
to the face (ant head):
+ Loss of pain (pinprick)
+ Loss of temperature

+ Decreased touch
E Loss een... Trigeminothalamic
Tract
Pain, temp, light
touch, fine touch,
Note: Think atthe vibratory & position
trigeminothalamic tract as sense from the
subserving the functions of contralateral face.
both the spinothalamic and
posterior column pathways
(medial lemniscus). But in this
case it relates to the head not

the body.

104. Cut, removed and
rotated 90 degrees.

Rt CN3 LESION:

«Rt eye down & out
+ Rt eye ptosis
+ Diplopia

Oculomotor Nerve
All ipsilateral
extraocular muscles
except sup oblique
& lat rectus.

Also upper eyelid,
light &
accommodation
reflexes.

Shine light into Rt Eye SS

+ No direct response
++ Consensual response

Shine light into Lt Eye
+ Direct res
+ No consensual response

105. Cut, removed and
rotated 90 degrees.

Anterior

CROSSED SYNDROMES IN
BRAINSTEM LESIONS

Ipsilateral cranial
nerve symptoms
with contralateral
symptoms involving
the ascending
sensory and
descending motor
pathways.

Ipsilateral CN3
symptoms

with contralateral
symptoms involving
the corticobulbar &
corticospinal paths.

106. This is the other portion of the midbrain. It contains CN4, which
innervates the contralateral inf oblique muscle. It is the only cranial
nerve to decussate & to exit posteriorly.

Posterior

Posterior % Anterior

Anterior

112. alamus and red nucleus

corticopontine—<
fibers superior cerebellar

peduncle

cerebellum

po

pontine
y fiber

middle
cerebellar

inferior cerebellar
peduncle

- proprioceptive
information from
spinocerebellar tract
(mossy fibers)

113. amus and red nucleus
corticopontine-

fibers superior cerebellar
_ peduncle

cerebellum

pon:

pontine
y fiber

inferior cerebellar
ped uncle

climbing fibers < proprioceptive
from jor olive information from
spinocerebellar tract

114. alamus and red nucleus

superior cerebellar
peduncle

cerebellum.

interposed
middle > fastigial
cerebellan
peduncle

inferior cerebellar
peduncle

climbing fibers d prioceptive
from inferior olive 1 information from
spinocerebellar tract
(mossy fib

116. Diencephalon

Cortex

Cingulate
6

Basal
Ganglia
|
Medial 1 J L- Hippocampus
Forebrain > /
Bundle

Pituitary

Gland R
Amygdala

mus + Hypothalamus + MFB

117. Figure AB-21: Thalamus Medial

Geniculate
Nucleus
\
\

Lateral
Geniculate
Nucleus

E ESG

Thalamus

128. Basics: Corticospinal System

In the caudal
medulla, the
system
crosses to
the opposite
side to
become the
lateral
corticospinal
tract of the
spinal cord.

al re The system arises primarily from

the motor cortex of the frontal
lobe in the dorsal and medial
areas.

Fibers destined for the leg area
of the spinal cord originate most
medially in the area supplied by
the anterior cerebral artery,
whereas fibers to the trunk and
upper extremity regions
originate more laterally and are
supplied by the middle cerebral
artery.

This is an UPPER MOTOR NEURON
system. It regulates the activity of the
anterior horn cells (LOWER MOTOR
NEURONS).

129. This system conveys pain,
temperature & light touch

* The information crosses to
the opposite side of the
cord near the entry level.

+ It then ascends through
the cord and brainstem as
the spinothalamic tract.

* It synapses in the
thalamus.

« It then is relayed via thala-
mocortical fibers through
the posterior limb of the
internal capsule (PLIC) to
the postcentral gyrus of the
parietal lobe.

130. Basics: Post Column Paths &
Bedlal Lemnisucs

This system conveys touch
(fine tactile), vibration and
position sense

1 The system from the lower
extremity is
called the fasciculus gracilis
and it is located most medially
in the posterior aspect of the
spinal cord.

3 In the caudal
medulla the
system crosses
and is then called
the medial
lemniscus as it
ascends through
the brainstem to
the thalamus.

4 It also is relayed
via thalamocor-
tical fibers through
the posterior limb
of the internal
capsule (PLIC) to
the postcentral
gyrus of the
parietal lobe.

2 The system from the upper
extremity is
called the

and it is located most laterally
in the posterior aspect of the
spinal cord.

131. Cerebellum Midsagittal & Ventrz

Vermis

Cerebellar Tonsil

Hemisphere

132. Horizontal View

E Substantia
Striatum

(Caudate & Putamen)

Hippocampus

Ceruleus

(Adrenergic)

Cerebellar Ath
Hemisphere Vermis Ventricle

133. « Ipsilateral loss

« Fasciulations

Spinal Cord

ANT HORN

« Abnormal EMG

SPINOTHALAMIC TR
« Lesions produce
contralateral loss
starting 1 or 2 levels
below lesion level

« Pinprick & temp

+ Light touch

« Lesions produce

« Weakness

POST COL PATHS
+ Lesions produce
ipsilateral loss

« Touch (fine)
« Vibration
« Position sense

CORTICOSPINAL

ipsilateral upper
motor neuron signs

Increased DTRs,etc.
Babinski sign