• The Brainweighs 350 g in the newborn and 1400 g in the adult.
  • The brain is classified into six postembryonic divisions:
  • Telencephalon
  • Diencephalon
  • Mesencephalon
  • Pons
  • medulla oblongata
  • cerebellum.
  • Telencephalon
  • consists of the cerebral hemispheres and the basal ganglia
  • The cerebral hemispheres contain the lateral ventricles.
  • Cerebral hemispheres consist of six lobes and the olfactory structures
  • Frontal lobe contains the following gyri:
  • Precentralgyrus - consists of the motor area (area 4).(MCQ)
  • Superior frontal gyruscontains the supplementary motor cortex on the medial surface (area 6).
  • Middle frontal gyruscontains the frontal eye field (area 8) (MCQ)
  • Inferior frontal gyruscontains the Broca speech area in the dominant hemisphere (areas 44 and 45) (MCQ)
  • Gyrus rectus and orbital gyriare separated by the olfactory sulcus.
  • Anterior paracentral lobule
  • is found on the medial surface between the superior frontal gyrus (paracentral sulcus) and the central sulcus.
  • represents a continuation of the precentralgyrus on the medial hemispheric surface.
  • Parietal lobe contains the following lobules and gyri:
  • Postcentralgyrusis the primary somatosensory area of the cerebral cortex (areas 3, 1, and 2).
  • Superior parietal lobulecomprisesassociationareasinvolvedinsomatosensoryfunctions(areas5and7)
  • Supramarginalgyrusinterrelates somatosensory, auditory, and visual input (area 40)
  • Temporal lobecontains the following gyri:
  • Transverse temporal gyri of Heschl is the primary auditory areas of the cerebral cortex (areas 41 and 42).
  • Superior temporal gyruscontains the Wernicke speech area in the dominant hemisphere (area 22).
  • Occipital lobecontains two structures:
  • Cuneuscontains the visual cortex (areas 17, 18, and 19).
  • Lingual gyrus(medial occipitotemporalgyrus) contains the visual cortex (areas 17, 18, and 19).
  • Insular lobe (insula)
  • Limbic lobe
  • is a C-shaped structure of the medial hemispheric surface
  • includes the following structures:
  • Paraterminalgyrus and subcallosal area
  • Cingulate gyrus
  • Parahippocampalgyrus
  • Hippocampal formation
  • is connected to the hypothalamus and septal area via the fornix.
  • includes the following three structures:
  • Dentate gyrus
  • Hippocampus
  • Subiculum
  • Olfactory structures
  • are found on the orbital surface of the brain and include:
  • Olfactory bulb and tract
  • Olfactory bulbreceives the olfactory nerve (cranial nerve [CN] I).
  • Olfactory trigone and striae
  • Anterior perforated substanceis created by penetrating striate arteries
  • Diagonal band of Brocainterconnects the amygdaloid nucleus and the septal area.
  • Basal ganglia
  • are the subcortical nuclei of the telencephalon.
  • Caudate nucleus
  • Putamen
  • Globus pallidus
  • Amygdaloid nuclear complex (amygdala)
  • What is striatum and lentiform nucleus (MCQ)
  • Striatum = Caudate nucleus + Putamen
  • lentiform nucleus = Globus pallidus + Putamen
  • Lateral ventricles
  • areependyma-lined cavities of the cerebral hemispheres.
  • containCSF and choroid plexus.
  • communicate with the third ventricle via the two interventricular foramina of Monro
  • are separated from each other by the septa pellucida.
  • Cerebral cortex
  • consists of a thin layer or mantle of gray substance.
  • is folded into gyri that are separated by sulci.
  • White matterincludes the cerebral commissures and the internal capsule
  • Cerebral commissures
  • interconnect the cerebral hemispheres
  • Corpus callosum
  • is the largest commissure of the brain.
  • interconnects the two hemispheres.
  • has four parts: Rostrum, Genu, Body ,Splenium
  • Anterior commissure
  • interconnects the olfactory bulbs and the middle and inferior temporal lobes.
  • Hippocampal commissure (commissure of the fornix)
  • Internal capsule
  • consists of the white matter
  • located between the basal ganglia and the thalamus.
  • has three parts:
  • Anterior limb
  • located between the caudate nucleus and putamen.
  • Genu
  • located between the anterior and posterior limbs.
  • containscorticobulbar fibers
  • Posterior limb
  • located between the thalamus and lentiform nucleus
  • Contains corticospinal fibers.
  • Diencephalon
  • is located between interventricular foramen and the posterior commissure.
  • receives the optic nerve (CN II).
  • consists of the epithalamus, thalamus, hypothalamus, subthalamus, and the third ventricleand associated structures.
  • Epithalamus
  • Pineal body (epiphysis cerebri)
  • Habenulartrigone
  • Medullary stria of the thalamus
  • Posterior commissure
  • mediates the consensual reaction of the pupillary light reflex.
  • Telachoroidea and choroid plexus of the third ventricle
  • Thalamus
  • consists of the following surface structures:
  • Pulvinar
  • Metathalamus
  • Medial geniculate body (auditory system)
  • Lateral geniculate body (visual system)
  • Hypothalamus
  • Optic chiasm
  • Mamillary body
  • Infundibulum
  • Tuber cinereum
  • Subthalamus (ventral thalamus)
  • Subthalamic nucleus
  • Zonaincerta and fields of Forel
  • Third ventricle and associated structures
  • Lamina terminalisresults from closure of the anterior neuropore.
  • Telachoroidea
  • Choroid plexus
  • Interventricular foramen of Monro
  • interconnects the lateral ventricle and the third ventricle.
  • Optic recess
  • Infundibular recess g. Suprapineal recess
  • Pineal recess
  • Mesencephalon (midbrain)
  • contains the cerebral aqueduct, which interconnects the third and fourth ventricles.
  • Ventral surface
  • Cerebral peduncle
  • Interpeduncular fossa
  • Oculomotor nerve (CN III)
  • Posterior perforated substanceis created by penetrating branches of the posterior cerebral and posterior communicating arteries.
  • Dorsal surface
  • Superior colliculus (visual system)(MCQ)
  • Brachium of the superior colliculus
  • Inferior colliculus (auditory system)(MCQ)
  • Brachium of the inferior colliculus
  • Trochlear nerve (CN IV)
  • is the only cranial nerve to exit the brainstem from the dorsal aspect.
  • Pons
  • Ventral surface
  • Base of the pons
  • Cranial nerves (MCQ)
  • Trigeminal nerve (CN V)
  • Abducent nerve (CN VI)
  • Facial nerve (CN VII)
  • Vestibulocochlear nerve (CN VIII)
  • Dorsal surface (rhomboid fossa)
  • Locus ceruleus
  • contains the largest collection of norepinephrinergic neurons in the CNS. (MCQ)
  • Facial colliculus
  • contains the abducent nucleus and internal genu of the facial nerve.
  • Sulcus limitans(MCQ)
  • separates the alar plate from the basal plate.
  • Striaemedullares of the rhomboid fossa
  • divide the rhomboid fossa into the superior pontine portion and the inferior medullary portion.
  • Medulla oblongata (myelencephalon)
  • Ventral surface
  • Pyramidcontains the corticospinal tract.
  • Olive contains the inferior olivary nucleus.(MCQ)
  • Cranial nerves
  • Glossopharyngeal nerve (CN IX)
  • Vagal nerve (CN X)
  • Accessory nerve (CN XI)
  • Hypoglossal nerve (CN XII)
  • Dorsal surface
  • Gracile tubercle
  • Cuneate tubercle
  • Rhomboid fossa
  • Striaemedullares of the rhomboid fossa
  • Vagal trigone
  • Hypoglossal trigone
  • Sulcus limitans
  • Area postrema (vomiting center) (MCQ)
  • Cerebellum
  • is located in the posterior cranial fossa.
  • is attached to the brainstem by three cerebellar peduncles.
  • forms the roof of the fourth ventricle.
  • is separated from the occipital and temporal lobes by the tentorium cerebelli.
  • consists of folia and fissures on its surface.
  • contains the following surface structures
  • Hemispheresmade up of two lateral lobes.
  • Vermisis a midline structure.
  • Tonsil
  • may herniate, with increased intracranial pressure, through the foramen magnum.
  • Superior cerebellar peduncle connects the cerebellum to the pons and midbrain.
  • Middle cerebellar peduncleconnects the cerebellum to the pons.
  • Inferior cerebellar peduncleconnects the cerebellum to the medulla.
  • Anterior lobe
  • Posterior lobe
  • Flocculonodular lobe