TOPOGRAPHY T1
Division of Cerebral Cortex into Lobes
1. Lateral View of Lobes in Left Hemisphere 2. Medial View of Lobes in Right Hemisphere
PARIETAL PARIETAL LIMBIC FRONTAL FRONTAL
INSULAR: buried OCCIPITAL OCCIPITAL in lateral fissure TEMPORAL TEMPORAL
3. Dorsal View of Lobes 4. Ventral View of Lobes
PARIETAL TEMPORAL LIMBIC FRONTAL OCCIPITAL FRONTAL OCCIPITAL
Comment: The cerebral lobes are arbitrary divisions of the cerebrum, taking their names, for the most part, from overlying bones. They are not functional subdivisions of the brain, but serve as a reference for locating specific functions within them. The anterior (rostral) end of the frontal lobe is referred to as the frontal pole. Similarly, the anterior end of the temporal lobe is the temporal pole, and the posterior end of the occipital lobe the occipital pole.
TOPOGRAPHY T2
central sulcus central sulcus
parietal frontal occipital
lateral temporal lateral sulcus sulcus SUMMARY CARTOON: LOBES SUMMARY CARTOON: GYRI
Lateral View of Left Hemisphere central sulcus postcentral superior parietal superior precentral gyrus gyrus lobule frontal intraparietal sulcus gyrus inferior parietal lobule: supramarginal and angular gyri middle frontal parieto-occipital sulcus gyrus
incision for close-up below OP
T preoccipital O notch inferior frontal cerebellum gyrus: O-orbital lateral T-triangular sulcus superior, middle and inferior temporal gyri OP-opercular
Lateral View of Insula central sulcus
cut surface corresponding to incision in above figure insula
Comment: Insula (insular gyri) exposed by removal of overlying opercula (“lids” of frontal and parietal cortex).
TOPOGRAPHY T3
Language sites and arcuate fasciculus. MRI reconstruction from a volunteer. central sulcus
supramarginal site (posterior Wernicke’s)
Language sites (squares) approximated from electrical stimulation sites in patients undergoing operations for epilepsy or tumor removal (Ojeman and Berger).
Broca’s site superior temporal site (anterior Wernicke’s)
arcuate fasciculus
supramarginal site (posterior Wernicke’s) superior temporal site (anterior Wernicke’s)
Broca’s site Dissection of arcuate fasciculus
transverse central sulcus arcuate fasciculus temporal gyrus visual radiation
caudate
Broca’s site
arcuate fasciculus
Broca’s region supramarginal site (posterior Wernicke’s) superior temporal gyrus
TOPOGRAPHY T4
Lateral Dissections
central sulcus cut surface of middle supramarginal gyrus frontal gyrus
lateral fissure
putamen middle temporal gyrus pons medulla external capsule spinal cord
pyramidal cell in central sulcus corona radiata precentral gyrus internal capsule
fiber in cerebral peduncle
fiber in base of pons
fiber in pyramid pyramidal decussation
TOPOGRAPHY T5
Dorsal View of Brain
LEFT HEMISPHERE RIGHT HEMISPHERE
longitudinal fissure middle frontal gyrus superior frontal sulcus
precentral sulcus
central sulcus precentral gyrus
postcentral sulcus postcentral gyrus
superior parietal lobule intraparietal sulcus
parieto-occipital fissure
occipital lobe Posterior View of Brain
longitudinal fissure falx lies between the cerebral hemi- parieto-occipital spheres in the longitu- sulcus dinal fissure
occipital lobe
tentorium lies between occipital lobes and cerebellum
cerebellum
medulla
T6
TOPOGRAPHY
B B parieto- central sulcus occipital fissure A A
lateral fissure
A corpus callosum FRONTAL LOBE longitudinal caudate fissure nucleus
thalamus central sulcus lateral fissure intraparietal lateral sulcus ventricle: posterior- horn parieto- occipital parieto- fissure OCCIPITAL LOBE occipital fissure B corpus callosum
caudate parieto- nucleus occipital fissure thalamus lateral occipital fissure pole lateral ventricle: inferior cerebellum horn
TOPOGRAPHY T7
Dorsal View of Brain
LEFT RIGHT
frontal lobe
genu of corpus callosum
body of corpus callosum
genu of corpus callosum
caudate nucleus occipital lobe splenium of corpus callosum internal capsule thalamus
transverse temporal gyrus
choroid plexus
posterior horn of lateral ventricle
splenium of corpus callosum
TOPOGRAPHY T8
Dorsal View anterior horn of lateral ventricle
caudate nucleus
internal capsule
thalamus
amygdala inferior horn of lateral ventricle hippocampus
fimbria
corpus callosum internal capsule
caudate nucleus amygdala
thalamus
fornix
inferior horn fimbria of lateral ventricle
hippocampus posterior horn of lateral ventricle
TOPOGRAPHY T9 Medial View of Right Hemisphere
central sulcus cingulate gyrus parieto-occipital fissure
corpus callosum: cuneus (cuneate gyrus )
calcarine body splenium fissure fornix septum genu pellucidum thalamus
cerebellar midbrain vermis lingual gyrus
pons subcallosal gyrus medulla superior and anterior commissure interventricular cerebral aqueduct and inferior colliculi optic chiasm foramen and fourth ventricle hypothalamus
Medial View of Right Hemisphere: Brain Stem and Septum Pellucidum Removed
cingulate gyrus
corpus callosum
fornix caudate isthmus of cingulate gyrus
subcallosal gyrus part of thalamus remaining after removal of brainstem
uncus fimbria at edge of hippocam- anterior pus (not seen) commissure
parahippocampal gyrus lamina terminalis optic chiasm column of fornix entering dissected hypothalamus
TOPOGRAPHY T10
Magnetic Resonance Scan: midline
septum pellucidum corpus callosum cingulate gyrus parieto-occipital fissure
calcarine fissure
superior and inferior fornix colliculi third ventricle cerebral aqueduct midbrain optic nerve pituitary fossa cerebellar vermis pons
medulla
spinal cord
fourth ventricle
TOPOGRAPHY T11
1. Septum Pellucidum, Hypothalamus & Most of Thalamus Removed parieto-occipital fissure fornix body of corpus callosum
cingulate gyrus calcarine sulcus
head of caudate nucleus anterior commissure vermis pons 2. Remaining Thalamus & Fornix Removed
cingulate gyrus head of caudate thalamus uncus cerebral peduncle nucleus genu of corpus callosum
parieto-occipital fissure
calcarine sulcus internal capsule
vermis
pons 3. Caudate Removed anterior commissure splenium of cingulum cingulate gyrus corpus substantia cerebral callosum nigra peduncle uncus
body of corpus callosum internal capsule
anterior commissure
vermis pons uncus substantia cerebral peduncle nigra TOPOGRAPHY OF THE CNS T12
Ventral View of Brain
frontal pole
olfactory bulb and olfactory tract orbital gyri
lateral sulcus
FRONTAL LOBE
optic nerve, optic chiasm and optic tract temporal pole
inferior temporal gyrus collateral sulcus
TEMPORAL LOBE floor of hypothalamus lateral and medial (tuber cinereum) occipitotemporal gyri mammillary body of hypothalamus BASE OF cerebral PONS peduncle parahippocampal gyrus trigeminal nerve flocculus MEDULLA (part of cerebellum) olive
CEREBELLUM tonsil pyramid (part of cerebellum)
occipital pole
Comment: The ventral surface of the brain is especially important. It is here that the blood supply to the brain enters. The brain stem and many of the cranial nerves are visible. In addition, one can see the cerebellum, portions of the frontal, temporal and occipital lobes, and the floor of the diencephalon. And it is also here that the pituitary gland (not shown) is attached to the hypothalamus by the small infundibulum (posterior to the optic chiasm). TOPOGRAPHY T13
Cranial Nerves: Numbers and Names
orbital gyri I . Olfactory bulb: olfactory nerves (in the nasal epithelium) terminate in the bulb. Olfactory tract straight (rectus) gyrus II. Optic nerve: The cell bodies of origin are in the retina. Half the axons cross (optic chiasm) to the opposite optic tract, half continuing to help form the optic tract of the same side. infundibulum and Optic chiasm and optic tract tuber cinereum
mammillary III. Oculomotor nerve body (nucleus)
cerebral IV. Trochlear nerve peduncle
pons middle cerebellar V. Trigeminal nerve peduncle VI. Abducens nerve VII. Facial nerve nerve
VIII. Vestibulocochlear nerve
pyramid
XII. Hypoglossal nerve rootlets olive
X. Vagus nerve rootlets
IX. Glossopharyngeal and XI. Accessory (cranial) nerve rootlets are too small to see here: position is rostral and caudal to the vagus in the same line TOPOGRAPHY T14
Ventral View Dissections olfactory tract frontal pole optic chiasm
hypothalamus temporal pole mammillary nucleus (body)
amygdala optic tract hippocampus uncus cerebral peduncle
parahippocampal gyrus substantia cerebral aqueduct nigra
splenium of corpus callosum occipital pole olfactory bulb infundibulum
amygdala optic tract inferior horn of lateral uncus ventricle
hippocampus parahippocampal gyrus
mammillary body
cerebral peduncle
midbrain
posterior horn splenium of of lateral ventricle corpus callosum TOPOGRAPHY T15
Ventral Dissection: Optic Radiation
RIGHT LEFT optic nerve, chiasm and tract olfactory bulb and tract middle cerebral artery infundibulum and hypothalamus hypothalamus dura
oculomotor cerebral peduncle nerve optic radiation: substantia temporal (Meyer’s) nigra loop
lateral geniculate
medial geniculate parahippocampal gyrus pulvinar
optic radiation splenium of corpus callosum midbrain dissected lower bank of calcarine fissure TOPOGRAPHY T16
BRAINSTEM
1. Medial view of right hemisphere corpus callosum
septum fornix pellucidum pineal anterior thalamus commissure superior & midbrain cerebellar inferior vermis colliculus
hypothalamus pons cerebral aqueduct optic medulla chiasm mammillary body fourth ventricle
3. Posterior view: cerebellum removed 2. Anterior view superior colliculus internal capsule inferior colliculus optic chiasm striatum and tract cerebral peduncle superior cerebellar hypothalamus cerebral peduncle peduncle pons cerebellar middle cerebellar hemisphere peduncle VIII flocculus inferior floor of inferior cerebellar olive tonsil medulla 4th ventricle peduncle pyramid
4. Lateral view from left side
cerebral peduncle cerebellar hemisphere optic trigeminal tract nerve (V)
flocculus hypothalamus pons tonsil pyramid inferior olive medulla