Neuroanatomy 1 — The Brain

Early development

formation of the neural tube:  neural groove and neural folds
Neural tube formation

cranial expansions [vesicles]

prosencephalon [forebrain]

mesencephalon [midbrain]

rhombencephalon [hindbrain]

flexures

cephalic

pontine

cervical

Parts of the embryonic brain

ventricles

development of the vesicles

forebrain

olfactory bulbs [rhinencephalon]

cerebral hemispheres [telencephalon]

optic vesicles

diencephalon

pineal body

infundibulum

mesencephalon

tectum [forms optic lobes in lower vertebrates]

corpora quadrigemina

hindbrain

cerebellum

pons

medulla oblongata

[metencephalon + myelencephalon]

Development of the skull

formation of the cranial vault bones
    frontal
    parietal
    temporal
    occipital
    sphenoid
    ethmoid

craniosynostosis

neonatal skull development

The meninges

dura mater

epidural space

periosteal dura

meningeal dura

subdural space

Cranial dura

arachnoid

subarachnoid space

Cranial meninges, showing dura and arachnoid

pia

Cranial meninges, showing arachnoid and pia

The whole brain

The whole brain

Brain stem 1
Very superficial dissection of the brainstem, and then some
Further dissection of the brainstem

medulla oblongata

fourth ventricle

inferior velum forms its roof
Schematic of the 4th ventricle

ascending and descending tracts

inferior cerebellar peduncles (restiform bodies)

decussation of the pyramids
Decussation of the pyramids

respiratory, vasomotor, cardiac centers

nuclei for cranial nn IX–XII
Cranial nerve nuclei

olivary nuclei [relay centers between cerebral cortex/basal nuclei and cerebellum]

reticular formation

pons

floor of the fourth ventricle

pontine nuclei

middle cerebellar peduncles

nuclei for cranial nn V–VIII

reticular formation

corticospinal, corticobulbar, and corticopontine tracts

Mesencephalon

midbrain [mesencephalon]

Hindbrain and midbrain

cerebral aqueduct (aqueduct of Sylvius)

cerebral peduncles

nuclei for cranial nn III–IV and anterior part of V

red nucleus and rubrospinal tract

superior cerebellar peduncle

corpora quadrigemina

superior colliculi [visual, auditory, tactile reflex centers]

inferior colliculi [auditory reflex centers]

Cerebellum 2, 6

anatomy

Upper surface of the cerebellum

peduncles

superior (brachia conjunctiva)... midbrain

middle (brachia pontis)... pons

inferior (restiform body)... medulla oblongata

Cerebellar connections

cerebellar hemispheres

vermis

cerebellar cortex

folia cerebelli

fissures

arbor vitae

layers

outer molecular layer [input]

Purkinje cell layer [output]

to deep cerebellar and lateral vestibular nuclei

inner granular layer [input]

Cerebellar cortex

functional considerations

functions quickly with no storage

coordination of somatic motor activity

regulation of muscle tone

maintenance of equilibrium

lesions

do not result in paralysis

ataxia 3

hypotonia 4 and asthenia

tremors and nystagmus 5

ipsilateral representation

Forebrain

diencephalon

Sagittal view of human brain

rostral limit is the interventricular foramina (foramina of Monro)

third ventricle
Coronal view of human brain through thalamus

lateral walls are the thalami

intermediate mass [variable, ~60%]

roof is the epithalamus

floor is the hypothalamus

thalamus

major sensory center

crude, uncritical consciousness [the reptilian brain]

lateral geniculate, medial geniculate, and ventral posterior nuclei
    important relay stations in the visual, auditory, and
    somatosensory systems, respectively

epithalamus

choroid plexus and the production of cerebrospinal fluid (CFS)

pineal body

posterior commissure where it joins midbrain

hypothalamus

optic chiasm

infundibulum

from tuber cinereum

The hypophysis cerebri

mammillary bodies

functions

regulation of body temperature, metabolism, sleep, emotions, sexual drive

integrated with endocrine system

Cerebrum

topology

Cerebrum, lateral view

Cerebrum, lateral view, with motor and sensory areas noted

longitudinal fissure

corpus callosum

surfaces:  dorsolateral, inferior, medial

poles:  frontal, occipital, temporal

cortex
Brodmann 7 areas

Colorized view of Brodmann areas  Simple map of Brodmann areas

lobes

frontal

parietal

gyri

sulci

lateral sulcus (Sylvian fissure)

insula

The insula

temporal lobe

primary auditory center:  Brodmann area 41 8, 9
secondary centers:  Brodmann areas 42, 22

frontal lobe

speech center:  Brodmann area 44

central sulcus (fissure of Rolando)

frontal lobe

precentral gyrus

primary motor cortex:  Brodmann area 4

Motor homunculus in the British Museum

parietal lobe

postcentral gyrus

somatesthetic cortex:  Brodmann areas 1–3

Sensory homunculus in the British Museum

calcarine sulcus

visual area:  Brodmann area 17

parietooccipital sulcus

parietal lobe

occipital lobe

sulcus cinguli parallels corpus callosum

Areas of localization on the medial surface of the cerebral hemisphere

gyrus cinguli:  smell association

collateral sulcus inferiorly

hippocampal gyrus lies medial

uncus:  smell & taste appreciation

association areas

white matter

Principal systems of association fibers in the cerebrum

association tracts

short association fibers

long association fibers

commissural tracts

corpus callosum

anterior and posterior commissural tracts

projection tracts

ascending [afferent] mostly from thalamus

descending [efferent]

corona radiata

basal nuclei ( basal ganglia ) 10

Basal Ganglia, showing connections between substantia nigra, putamen, globus pallidus and subthalamic nucleus

The slightly strange site of the Lieberman Parkinson Clinic

striatum

putamen, caudate nucleus, nucleus accumbens

claustrum, amygdaloid nucleus, substantia nigra, &
globus pallidus [putamen + globus pallidus=lentiform nucleus]

subthalamic nuclei

internal capsule [between caudate and lentiform nuclei]

external capsule [outside of lentiform nucleus]

claustrum [lies lateral to external capsule]

conditions linked with basal-nuclei dysfunction:
   Parkinsonism
   Huntington’s chorea
   Tourette syndrome
   athetosis
   obsessive-compulsive disorder

conditioned reflexes

Pavlovian conditioning

milk let-down

Ventricles of the brain

Ventricles of the brain
Ventricles of the brain

fourth ventricle

choroid plexus

capillaries are part of pia, but covered with ependymal cells

production of CSF

median aperture (foramen of Magendie)

lateral aperture (foramina of Luschka)

hydrocephalus

cerebral aqueduct (aqueduct of Sylvius)

lies within mesencephalon

third ventricle

choroid plexus

interventricular foramina (foramina of Monro)

lateral ventricles

septum pellucidum

central portion

choroid plexus

anterior, posterior, and inferior horns

arachnoid villi of the superior sagittal sinus

Meninges of the brain

dura mater

periosteal dura

meningeal dura

falx cerebri

superior and inferior sagittal sinuses

Arachnoid granulations

tentorium cerebelli

transverse and superior petrosal sinuses

straight sinus

falx cerebelli

occipital sinus

diaphragma sellae

arachnoid

subdural space

subarachnoid space

arachnoid trabeculae

over the gyri, pia + arachnoid=leptomeninx

cisterns

arachnoid villi

pia mater

Blood supply to the brain

common carotid a

external carotid a

internal carotid a

enters carotid canal

posterior communicating a

ophthalmic a

anterior cerebral a

middle cerebral a

subclavian a

internal thoracic a

thyrocervical trunk

costocervical trunk

vertebral a

through transverse processes of superior six cervical vertebrae

spinal branches

anterior spinal a

cerebellar branches

posterior inferior cerebellar a

anterior inferior cerebellar a

forms basilar a

posterior cerebral aa

circle of Willis (circulus arteriosus cerebri)

R posterior cerebral a -> R posterior communicating a ->
R internal carotid a -> R anterior cerebral a ->
anterior communicating a -> L anterior cerebral a ->
L internal carotid a -> L posterior communicating a ->
L posterior cerebral a -> basilar a bifurcation ->
R posterior cerebral a ->...



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