SURFACE ANATOMY OF THE BRAIN AND SPINAL CORD

Belinda Lioba L. Mesina, MDYear Level I Neurology

Divisions of the Nervous System

NERVOUS SYSTEM

Central Nervous System

Brain

Spinal Cord

Peripheral Nervous System

Cranial and Spinal

Nerves, their associated ganglia and peripheral receptor organs

Divisions of the Nervous System

NERVOUS SYSTEM

Central Nervous System

Brain

Spinal Cord

Peripheral Nervous System

Cranial and Spinal

Nerves, their associated ganglia and peripheral receptor organs

Brain

The Brain

Semisolid Weighs approximately 1.4kg Constitutes about 2% of total body

weight

The Brain

Cerebral hemispheres

Brain stem Diencephalon Mesencephalon Pons Medulla

oblongata

Cerebellum

Embryologic Divisions

External Barriers of the Brain

Skull

Meninges Dura mater Arachnoid mater Pia mater

Cerebrospinal Fluid

Skull

Skull

Skull

Major Reflections of the Dura Mater

Falx cerebri Falx

cerebelli Tentorium

cerebelli Diaphragma

sella

The Brain: Orientation

Cerebral HemispheresCerebral cortex, white matter, basal ganglia

Cerebral Cortex

Gyrus Sulcus/Fissure 4 lobes

Frontal Parietal Temporal Occipital

Longitudinal Fissure

Central Sulcus

Lateral Surface: Frontal Lobe

Precentral gyrus Primary motor area

Premotor area Superor and inferior

frontal sulci Superior frontal gyrus Middle frontal gyrus Inferior frontal gyrus

Anterior horizontal rami Anterior ascending rami▪ Pars orbitale, triangularis,

opercularis Orbital gyri – inferior of

frontal lobe

Motor Homunculus

Lateral View: Parietal Lobe

Post central gyrus Primary

somesthetic area Intraparietal

sulcus Parieto-occipital

sulcus Superior parietal

lobule Inferior parietal

lobule Supramarginal

gyrus Angular gyrus

Sensory Homunculus

Lateral View: Temporal Lobe

Superior and inferior temporal sulci

Superior temporal gyrus Transverse gyri

of Heschl▪ Primary auditory

area Middle temporal

gyrus Inferior temporal

gyrus

Transverse Gyri of Heschl

Lateral View: Occipital Lobe

Above the tentorium cerebelli

Parieto-occiptal sulcus

Contains a portion of the primary visual area

Medial Surface

Medial View: Occipital Lobe

Parieto-occipital sulcus

Calcarine sulcus Cuneus Lingual gyrus Primary visual

cortex

Olfactory sulcus Olfactory bulb

and tract Gyrus rectus Orbital gyri Parahippocampa

l gyrus Uncus

Primary olfactory complex

Inferior Surface 0f the Frontal Lobe

Inferior Surface of Temporal Lobe

Lies in the middle fossa of the skull Inferior

temporal gyrus Occipito-

temporal gyrus▪ Collateral sulcus

Parahippocampal gyrus▪ Uncus

Insula

Insula

Functional Regions of the Cerebral Cortex

Broadmann Areas

BrainstemDiencephalon, Mesencephalon, Pons, Medulla Oblongata

Brainstem

Diencephalon

“In-between brain” 4 major

subdivisions: Epithalamus▪ Stria medullaris

thalami▪ Habenular nuclei▪ Pineal gland

Thalamus Subthalamus Hypothalamus

Diencephalon: Limbic System

DiencephalonOptic nerve

Optic chiasm

Optic tract

Infundibular stalk

Mammillary bodies

Mesencephalon: Ventral Surface

Cerebral peduncle

Oculomotor nerve

Interpeduncular fossa

Trochlear nerve

Mesencephalon: Dorsal Surface

CORPORA QUADRIGEMIN

A

Superior colliculi

Inferior colliculi

Pons: Ventral Surface

Pontine protuberance/

sulcus

Trigeminal nerve

Abducens nerve

Facial nerve

Cochleovestibular nerve

Pons: Dorsal Surface

Floor of the fourth ventricle

Facial colliculi

Medial sulcus

Cerebral peduncle(cut surface)

Medulla: Ventral Surface

Inferior olive

Anterior lateral sulcus

Pyramid

Anterior median sulcus

Glossopharyngeal nerve

Vagus nerve

Hypoglossal nerve

Accessory nerve

Medulla: Dorsal SurfaceHypoglossal

trigone

Vagal trigone

Restiform body

Posteromedian sulcus

Clava

Posterointermediate sulcus

Cuneate tubercle

Posterolateral sulcus

Tuberculum cinereum

Cerebellum

Cerebellum

“Small brain” ~150 g (10% of

Body Weight) 1000 cm2 surface

area (40% of cerebral cortex)

Located in the posterior fossa of the skull

Overlies the dorsal portion of the pons and medulla

Roof of 4th ventricle

Cerebellum: Superior Surface

Cerebellar hemispheres

Vermis Anterior and

posterior cerebellar notch

Primary fissure Postlunate

fissure (superior posterior)

Cerebellum: Inferior Surface

Flocculonodular lobe

Posterolateral fissure

Cerebellar tonsils

Inferior vermis Horizontal

fissure

Lobules of the Vermis

1 – Lingula2 – Central Lobule

3 – Culmen

Primary (Tentorial) Fissure

4 – Declive5 – Folium

Horizontal (Petrosal) Fissure

6 – Tuber

Prepyramidal ( Suboccipital) Fissure

7 – Pyramis8 – Uvula

9 – Nodulus

Lobules of the Hemispheres: Superior Surface

Wing of the central lobule

Quadriangular lobule

Superior semilunar lobule

Inferior semilunar lobule

Lobules of the Hemispheres: Inferior Surface

Biventer lobule

Tonsils Inf.

semilunar lobule

Sup. semilunar lobule

Flocculus

Cerebellum: Anatomic Subdivisions

Cerebellum: Functional Subdivisions

Functional Subdivision

Anatomically corresponds

to...

Has reciprocal connections

with...

Function

Vestibulocerebellum

Flocculonodular lobe

Vestibular and reticular nuclei

Body equilibrium and eye movement

Spinocerebellum

Anterior lobe Spinal cord Control of muscle toneAxial and limb movements

Cerebrocerebellum or Pontocerebellum

Posterior lobe Cerebral cortex Planning and initiation of movementsDiscrete limb movements

Cerebellum: Phylogenetic Subdivision

Archicerebellum Oldest zone Corresponds to the flocculonodular lobe

Paleocerebellum Corresponds to the anterior lobe and

part of the posterior lobe Neocerebellum

Most recent phylogenetically Corresponds to the posterior lobe

Cerebellar Peduncles

Superior/Brachium conjunctivum Midbrain

Middle/Brachium pontis Pons

Inferior/ Restiform and juxtarestiform bodies Medulla

Somatotopic Representation

Spinal Cord

Divisions of the Nervous System

NERVOUS SYSTEM

Central Nervous System

Brain

Spinal Cord

Peripheral Nervous System

Cranial and Spinal Nerves, their associated ganglia and peripheral

receptor organs

Spinal Cord

Spinal Cord Development

Newborn: L3 Adult: L1 – L2 Vertebral column

grows faster than the spinal cord

Spinal Cord Runs through the vertebral

canal, from foramen magnum to second lumbar vertebra

Regions Cervical (8) Thoracic (12) Lumbar (5) Sacral (5) Coccygeal (1)

31 pairs of spinal nerves (mixed)

Enlargements Cervical : upper limbs Lumbar : lower limbs

Caudal End of Spinal Cord

Conus medullaris

Filum terminale

Cauda equina

Meninges of the Spinal Cord

Spinal Cord Organization

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Cerebral Dural Sinuses

Superior sagittal sinus

Great cerebral vein (Galen)

Ophthalmic veins

Facial vein

Cavernous sinusInferior petrosal sinus

Internal jugular vein

Sigmoid sinus

Superior petrosal sinus

Transverse sinus

Straight sinus

Inferior sagittal sinus

Occipital sinus

Dermatomes and Myotomes

Spinal Cord Organization