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The A to Z of
The Brain
Dr A. L. NeillBSc MSc MBBS PhD FACBS
Dr A. L. NeillBSc MSc MBBS PhD FACBS
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INTRODUCTION
This is the 6th in the series of the A to Zs.
It continues on where theA to Z of the Head & Neckleft off and
continues with some of the new features of the evolving series original.
It is the first book of an organ in that the Brain and CNs is a whole
with multiple parts. Clinical considerations are maintained. As usual
feedback plays an extremely important role in this, please feel free to
comment and contribute to any and all aspects of these publications
after all they are for you whoever you, the reader may be.
We have a website where you can view all images of the A to Zs and
other material and from which you make comments:
http://www.aspenpharma.com.au/atlas/student.htm
ACKNOWLEDGEMENT
Thank you ASPENpharmacare Australia for your support and assistance
in this valuable project, particularly Mr. Greg Lan CEO of
Aspenpharmacare Australia, Rob Koster, Richard Clements and Ante
Mihaljevic and everyone who provided valuable feedback.
DEDICATION
To those striving to understand.
HOW TO USE THIS BOOK
The structure of the A to Z books has by necessity changed slightly.
The principle of listing all the structures in an alphabetical manner and
hence making the book its own index for easy retrieval has been
maintained, but because of the complexity of this material, it has beennecessary to do this after first dividing the material into a number of
main topics as was the case in the A to Z of the Head & Neck.
Thank you
Amanda Neill
BSc MSc MBBS PhD FACBS
SBN 978-0-9806840-2-5
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Table of contentsIntroduction 3 Acknowledgement Dedication 3
How to use this book 3Table of contents 4
Abbreviations
Common Terms used in Neurology Neuroanatomy 10
Guide to Anatomical Planes and Relations 24
Anatomical movements
The Nervous system overview 28The Nerve Cells overview 30
The Brain and SC overview 32
Blood brain barrier 32
Blood supply 34
CSF 38
Development and Organization 40Macroscopic structure 42
Fibrous tracts 44
Meninges coverings 46
Dura Mater 46
Meninges and the Brain 48
Meninges and the SC 50
Neurological assessment 52
Headache 52
History 52
Examination - conscious patient 56unconscious patient 57
THE BRAINBlood supply overview
Blood Vessels and Meningeal layers of the Brain 60Brain Arteries - overview see also Cerebrum / arteries 64Brain Veins - overview 66Cranial Venous Sinuses 68Cavernous sinus 68Petrosal sinuses see Sagittal sinuses
Sagittal sinuses 70Straight sinus see Veins overview & Sagittal sinusesTransverse sinus see Veins overview & Sagittal sinuses
Brodmanns areas see Cerebrum
Circle of Willis = Cerebral arterial circle 72
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Topography
Macroscopic components of the Brain 74
Outer surfaces see also Gyri & Sulci
InferiorLateralPosteriorSagittal - Median = mid-sagittal
Superior see Cerebrum
Gyri + Sulci / Outer surfaces 78
Dissections Sectional Anatomy 84Coronal sectionsSagittal sections see also Median section 90Transverse sections see also Coronal sections 92
REGIONSAmygdala / Amygdaloid bodies see Fornix
Angula gyrus see Cerebrum/lobes
Anterior Commissure
Anterior Perforating substance see Brain outer surfaces / inferior
Basal ganglion/nuclei see also Brainstem and Diencephalon 96
Basis Pedunculi = Crus cerebri see Brainstem Midbrain
Brainstem = Midbrain + Pons + Medulla Oblongata 98 Arteries CN nuclei see Cranial Ns
Brocas area see Language centresBulb = Medulla Oblongata see Brainstem , Midbrain
Cerebrum - Arteries Brodmanns areas and maps of the cerebral cortex 106Examination of CH - cognitive skills 113Lobes Cerebrum Major anatomy 114
Sections coronal / transversesee Dissections/Coronal, Transverse
Caudate nucleus see Basal nuclei
Cerebellum 122
Choroid plexus see Basal Nuclei, CSF, Ventricles
Cingulate gyrus see Cerebrum/lobes
Claustrum see Anterior commissure
Colliculi - superior & inferior bodies see Brainstem
Corpus Callosum see also the Brain Dissections Sagittal 124
Corpus striatum = Caudate nucleus + Lentiform nucleus see Macroscopic structure, Basal Nuclei
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Crus Cerebri see Brainstem Midbrain
Cuneus see Lobes - Occipital, Brain sagittal
Dentate nuclei see Brainstem, Cerebellum, Limbic system
Dermatomes (of the Face) see Cranial Ns and Special senses / CN V Trigeminal N
Diencephalon = Epithalamus + Hypothalamus + Thalamus 126
Dura Mater see Meninges coverings
Ependyma see Ventricles
External Capsule see Brain/sections/coronal
Falx Cerebri see Meninges brain coverings
Fornix see also Septum Pellucidum 128Frontal lobe see Brain - Outer surfaces / Cerebrum Lobes
Geniculate bodies lateral / medial see Brainstem, Midbrain
Globus Pallidus see Anterior Commissure
Habenular nucleus see Basal nuclei, Hypothalamus
Hippocampus see Fornix, Limbic system
Hindbrain see Brainstem, MidbrainHypothalamus see Basal nuclei, Diencephalon
Inferior Colliculus see Brainstem
Infundibulum see Brain/outer surfaces/inferiorInsula see Cerebrum/lobes
Internal Capsule see Brain/sections/coronal
Language centres see also Pathology / Aphasia 130
Lateral Sulcus = Sylvian fissure see Cerebrum/lobes, Gyri + Sulci
Lentiform Nucleus = Globus Pallidus + Putamensee Basal nuclei, Hypothalamus
Limbic system see also Fornix 132
Mammillary bodies (AKA Mammilary) see Fornix, Limbic system
Medulla Oblongata = Medulla see Brainstem , Midbrain
Midbrain = Mesencephalon see also Brainstem 134Nucleus Accumbens = septal nuclei see Basal Nuclei, Fornix
Obex see Ventricles
Operculum see Cerebrum /lobes
Optic radiation see CN II
Paraterminal gyrus = Subcallosal gyrus
see Anterior commissure, Septum PellucidumPineal body/gland see Brain- Outer surfaces - Median
Pons see Brainstem, Midbrain
Precuneus see Cerebrum/lobes, Brain sagittal
Pulvinar (part of the Thalamus) see Thalamus
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Putamen see Basal Nuclei
Red Nucleus see Brainstem, Midbrain, Rubrospinal tract
Rhinencephalon = the Olfactory region of the brain see Septum Pellucidum, CN I
Septum Pellucidum 136
Striate body = Corpus Striatum
Substantia Nigra see Brainstem
Superior Colliculus see Brainstem
Sylvian fissure = Lateral Sulcus see Cerebrum
Tela Choroidea see, Hypothalamus, Ventricles
Thalamus see also Basal ganglia & Diencephalon 138Uncinate Fasciculus see Anterior Commissure
Vallecula see Cerebellum
Ventricles 142
Vermis see Cerebellum
Wernickes area see Language centres
THE CRANIAL NERVES & SPECIAL SENSESOverview and summary 148
BS to the CNs and Relations see the Brain veins
CN I see also Special senses / Smell & Taste 152
CN II see Brain outer surfaces /inferior; Special senses / Sight
CN III see also Special senses / Sight 153
CN IV see also Special senses / Sight 156CN V 158
CN VI see also Special senses / Sight 172
CN VII see also Brainstem CN nuclei / Special senses / Taste 174
CN VIII see Special senses / Sound and Balance 182
CN IX see also Special senses / Taste 186
CN X see also Special senses / Taste 188CN X special anatomy Larynx 192CN X +ANS 194
CN XI see also CN IX X & XI 200
CN IX, X & XI neural pathways & interrelationships 202
CN XII 206
SPECIAL SENSESSight = Vision + Focus and eye movement -Vision- CN II 210Visual field defects 214Control of eye movement and focus - CN III, IV & VI 216
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see also Venous sinuses/Cavernous sinus
Smell & Taste - 222Smell - CN I see RhinencephalonTaste CN VII, IX & X
Sound + Balance 228CN VIII
Examination of the CNs - 230
Reflexes of the CNs - 238
THE SPINAL CORD Ascending = Sensory tracts 250
Anterolateral system = Spinothalamic +Spinoreticular tracts (pain & temperature) see Pain pathwaysDorsal columns = Fasciculi Cuneatus + Gracilis(touch, proprioception & vibration)Spinocerebellar tracts = anterior + posterior spinocerebellartracts see Dorsal ColumnsSpinothalamic tracts = anterior + lateral spinothalamic tracts 252see also Pain pathways
Descending = Motor tracts 254Anterior corticospinal tracts = uncrossed pyramidal tractssee Corticospinal tractsCorticobulbar = Rubrospinal see Pyramidal tractsCorticospinal = anterior + lateral corticospinalExtrapyramidal tracts = Tectospinal + Vestibulospinal +Spinocerebellar tracts see Tracts of the SC
Lateral corticospinal tracts = crossed pyramidal tractssee Pyramidal tractsPyramidal = corticobulbar tracts + corticospinal tracts 256Rubrospinal = Corticobulbar see Pyramidal tracts
Nociceptive information see Pain pathways
Pain pathways 258Overview of tracts of the SC 260
Points of immobility 262
Relations with the ANS 264
Sensory modalities eg pressure, proprioception, temperature, touch,vibration see Tracts of the SC for description of individual modalities
Structure overview see The Brain and SC - overview
Tracts of the SC
Examination of the SC, Spinal N roots and PNssee the A to Z of the Bones, Joints & Ligaments and the Back &The A to Z of the Peripheral Nerves
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Abbreviations A = actions /movements
of a joint A = anteriorACF = anterior cranial fossaaka = also known asalt. = alternative
AM = arachnoid materANS = autonomic nervous systemant = anteriorart = articulation (joint w/o the
additional support structures) AS = Alternative Spelling,generally referring to the diff.b/n British &
American spellingassoc. = associated withBBB = blood brain barrierbc = because
BP = brachial plexusBS = blood supplyBS = brain stemb/n = betweenC = cervical / carpalCC = cerebral cortexc.f. = compared toCF = cranial fossa(e)
CH = cerebral hemispheresCN = cranial nerveCNS = central nervous systemCO = cardiac outputCo = coccygealCoP = coccygeal plexuscollat.= collateralCr = cranial
CSF = Cerebrospinal fluidCT = connective tissueDH = dorsal horn (of the spinal cord)dist. = distalDM = dura matere.g. = exampleEC = extracellular (outside the cell)Gk. = GreekGM = grey matterHp = HippocampusIC = intracellular / intercostalIC = intercarpalIMC = intermetacarpal
jt(s) = joints = articulations
L = lateralL = left / lumbarLL = lower limbLt. = Latinlig = ligamentM = materMB = midbrainMC = metacarpalMCF = middle cranial fossamed = medialMO = medulla oblongata (medulla)MN = myelinated nerve
nMN = non-myelinated nerveN = nerveNS = nervous system/nerve
supplyNT = nervous tissueNTr = nerve tract / trunkP = posteriorPaNS = parasympathetic nervous
systemPCF = posterior cranial fossapl. = pluralPM = pia materPN = peripheral nervepost. = posteriorproc. = processprox. = proximal
R = RightRC = radiocarpalS = sacralsing. = singularSc = spinal canalSC = spinal cordSN = spinal nerveSP = spinous process
SyNS = sympathetic nervous systemT = thoracicTP = transverse processUL = upper limb, arm
V = vertebra VB = vertebral body VC = vertebral column VH = ventral horn (of the spinalcord)
Ven = ventricle (of the brain)WM = white matterw/n = withinw/o = without
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Neuro-anatomical and Neurological terms Action potential the generation of a N impulse through stimulation and
depolarizing of the N cell membrane
Acusis hearingAdiadochokinesia inability to rapidly perform rapidly alternating movements
Afferent incoming - as with sensory fibressee Sensory
Agnosia w/o knowledgeinability to recognize sensory stimuli
(auditory, tactile, visual)
Agraphia w/o writing- inability to write coherently due to a
cerebral lesion
Ala cinerea ashen hued wing - triangular region on the floor of the4thVen one of the Vagal nuclei
Alexia w/o words- inability to grasp the meaning of words
Allocortex the older cerebral cortex = archicortex + paleocortex
Alveus trough thin WM layer covering the ventricular
surface of the Hp
Amacrine long- the N cell type with long fibrous processes in
the retina
Ammons horn Ammonis = Egyption god with a rams head used for
the Hp which sagittally has a curl like a rams horn
Amygdala almond- almond shaped body in the Temporal lobe
involved in memory & emotion
Anasthesia w/o feeling- loss of sensation
Angular gyrus part of the Temporal lobe involved in languageprocessing, letter shape and word recognition,
connects occipital cortex with Wernickes area
Anopsia w/o sight- defect of vision
Ansa - loop- a loop like structure eg Ansa Cervicalis
Ant. Cingulate gyrus part of the limbic system - assoc. with cognitive processing
of pain perception and emotional response (see cingulum)
Antidromic N impulse running up the axon or down the dendritein the opposite direction
Aperture an opening or space b/n bones or w/n a bone.
Aphasia w/o speech- loss of speech or comprehension of the
written and spoken word
Apraxia w/o being able to do- inability to move purposefully
w/o paralysis
Arachnoid spidery weblikeeg AM
Archeocortex AS Archiocortex part of the 3 layered Allocortex in the
Limbic system mainly in the Hp and Dentate gyrus
Archicerebellum AS Archeocerebellum old part of the little brain to do
with balance
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Area postrema caudal area on the floor of the 4thVen
Articulation joint, which is a point of contact b/n 2 bones / relating
to a joint. - hence articular branches of a N supply the
joint described.
Association fibres those N fibres which connect cortical areas of thebrain ipsilaterally (as opposed to commissural fibres)
Astereognosis w/o solid shape- inability to recognise basic shapes
by feeling them
Astrocytes star- one of the supportive cell types in the CNS (see Glia)
Asynergy w/o work- disturbance in the muscle contraction
sequence in doing a coordinated act
Ataxia w/o orderinability to contract muscles in order and
hence weakness in contraction
Athetosis w/o positioninability to keep fingers or toes in a still
position continually writhing of the extremities due
to degeneration in the CC and Corpus Striatum
Autonomic automatic motor innervation of the viscera
Axial axis- refers to the head and trunk (vertebrae, ribs andsternum) of the body.
Axolemma plasma membrane of the axon
Axon N process carrying material away from the cell body
to the target organ, each N has only one axon
Axon collaterals branches of the axon
Axon hillock part of the N where the axon rises and has no Nissl bodies
Axoplasm cytoplasm of the axon
Baroreceptor weight receiversensory N fibre which responds to
pressure changes as in the carotid canal
Basal ganglia incorrect term for cluster of Ns buried in the WM of the
brain and involved in movement includes: CAUDATE
NUCLEUS + PUTAMEN + GLOBUS PALLIDUS +
SUBSTANTIA NIGRA
Basilar relating to the base or bottom of structures
Basiocranium bones of the base of the skull
Basis pedunculi (see crus cerebri)
Bipolar neurons with 1 dendrite + 1 axon (see unipolar, multipolar)
Blood brain barrier = BBB the barrier protecting the brain from certain
substances found in the BS
Brachium arm- large bundle of N fibres joining one region to anotherBradykinesia abnormally slow movements
Brainstem MO + Pons + Midbrain
Brocas area central region of the L frontal lobe of the CC - involved
in the production of speech: - word perception,
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production, sound and memory
Brodmanns areas areas of the CC which have been designated by their
histology cytoarchetecture - and later analysed and
found to have specific functions (after Korbinian
Brodmann 1909)Bulb old term for MO / in the corticobulbar tract refers to
the that part of the brain stem containing the motor
nuclei of the CNs
Calamus Scriptorius reed / pen- caudal part on the floor of the 4thVen
which looks like a pen
Calcar spuras in the Calacarine sulcus of the Occipital lobe
Canal tunnel / extended foramen as in the carotid canal, at
the base of the skull adj canular (canicular - small canal)
Caput relating to the skull
Carotid to put to sleep; compression of the common or
internal carotid artery causes coma. This refers to
bony points related to the carotid vessels
CAT scan = computerized axial tomography scan computer
mediated Xray image depicting a crossection of the
body see also CT scan
Cauda equina horses tail- lumbar and sacral N roots of the SC
resembling a horses tail
Caudate nucleus tailnucleus in the Corpus Striatum, having a long tail
Cavity an open areahence an open area or sinus w/in a bone
or formed by 2 or more bones (adj. cavernous), maybe used interchangeably with fossa. Cavity tends to
be more enclosed fossa a shallower bowl like space
(Orbital fossa-Orbital cavity).
Central sulcus major groove in the coronal plane dividing the frontal
and parietal lobes
Cephalic pertaining to the head
Cerebellum little brain the brain situtated in the PCF - to do withmotor coordination, balance and posture same
structure as the Cerebrum 2 hemispheres cortex
and medulla - only smaller
Cerebrospinal fluid = CSF fluid - fluid surrounding the brain and SC formed
by the ependymal cells from filtered blood. It is part of
the BBB, and contains sugar, urea and protein - approx
125mls and flows around the brain and SC at any time.Cerebral cortex GM interconnection b/n the 2 sides via the
Corpus Callosum
Cerebral hemispheres = CH L mainly to do with: speech, writing, language
& calculation R mainly to do with spatial abilites, face
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recognition, music perception and production
- see Cerebrum
Cerebro-spinal fluid = CSF , fluid surrounding the Brain + SC providing
insulation, nutrition and pressure
Cerebrum Brain the major 2 hemispheres of the brain consisting of an outer cortex of Ns = GREY MATTER
GM) + inner medulla of N fibres WHITE MATTER (WM)
Chiasma (Gk = ) used for the crossing of the Optic fibres
Chorea dance irregular, involuntary, movements of the limbs
and face due to degen. of the neostriatum
Choroid AS Chorioid delicate membrane as in the choroid
plexus in the brain or the retina
Cinerea ashes / ashen colour / grey as in Tuber Cinereum -
ventral portion of the Hypothalamus
Cingulate gyrus part of the Limbic System, directly above the corpus
callosum on the medical surface of the CH to do with
emotion and attention
Cingulum girdleas in a bundle of association fibres in the WM of
the Cingulate gyrus of the CH, medial surface
Claustrum barrier - thin sheet of GM b/n Lentiform nucleus and
the Insula
Cochlea a snail hence snail-like shape relating to the Organ of
Corti in the middle ear (adj. cochlear)
Cognition to know a processing of knowledge for use in higher
functions as in recognition and recall for use inproblem solving etc
Colliculus small elelvation / mound e.g. superior and inf.
colliculi forming the tectum of the MB Facial
colliculus on the floor of the 4thVen
Commissural fibres those N fibres crossing the Median plane in the brain
or SC (e.g. anterior commisure)
Commissure joining together- a decussation or crossing of largegroups of fibres from one side of the median plane to
the other in the brain or SC
Cordotomy AS Chordotomy sectioning of spinothalamic tract for
intractable pain (also tractotomy)
Contra opposite(as opposed to ipsi the same)
Contralateral on the opposite side (as opposed to ipslateral on the
same side)
Corona crown fibres radiating from an inner point outwards
- as in the Corona Radiata fibres from the internal
capsule to the CC
Corpus Callosum hard body the main neocortical commissure of the
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CH connects the 2 CH via large mass of axons
crossing from one side to the other
Corpus Striatum striped body- mass of GM with motor functions at the
base of each CH
Cortex outer rind / bark outer GM of the cerebrum andcerebellum
Cortical plasticity ability of connections b/n Ns of the CC to change
Cranial Nerve (CN) N coming directly from the brain not the SC
Cranium the cranium of the skull comprises all of the bones of
the skull except for the mandible.
Crest prominent sharp thin ridge of bone formed by the
attachment of muscles particularly powerful ones e.g.
Temporalis/Sagittal crest
Crus leg e.g. Crus Cerebri - the ventral part of the
Cerebral Peduncle of the MB
CT scan = computerized axial tomography scan computer
mediated Xray image depicting a cross-section of the
body see also CAT scan
Cuneus wedge e.g. gyrus on the medial surface of the CH
Fasciculus Cuneatus of the MB & SC
Cutus skin- hence cutaneous branches refer to the Ns
supplying the skin & adnexae
Declarative memory memory of words which can be recalled
Decussation X - a crossing of paired N fibres inside the CNS e.g. in
the pyramids, medial leminisici and superiorcerebellar peduncles
Dendrite(s) tree- N process(es) bringing communication to the
cell body
Dentate toothed e.g. Dentate nucleus in cerebellum
Dentate gyrus in the Temporal lobe
Depolarization the loss of the potential across the cell membrane of a
N due to stimulation and formation of a N impulse(see repolarization)
Dermatome the cutaneous innervation of a SN
Diencephalon through the brain= Epithalamus + Thalamus +
Subthalamus + Hypothalamus
Diplopia double vision
Distal further away from the axial skeleton
(opposite of Proximal)
Dura hard as in DM thick external layer of the meninges
Dyskinesis disordered movement abnormal motor function with
involuntary purposeless movements
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Dysmetria disordered measure abnormal reach or control of
muscle action
Efferent outgoing as in Motor nerves - see Motor
Emboliform plug e.g. emboliform nucleus of the cerebellum
Endocranium w/in the skull- refers to the interior of the braincaseadj. endocranial divided into the 3 major fossae
anterior (for the Frontal lobes) middle (containing
Temporal lobes) and posterior (for the containment of
the Cerebellum).
Endoneurium w/in the N- innermost of the CT coverings of a PN
fibre (see neurium, perineurium and epineurium)
Engram mark a lasting memory memory picture from a
past experience
Entorhinal w/in the nose the entorhinal area lies in the ant. of
the parahippocampal gyrus in the lateral olfactory area
Ependyma/
Ependymal cells line the ventricles and the central canal of the SC
(see Glia)form the CSF
Epineurium upon the N - outermost of the CT coverings of a PN
fibre (see neurium, perineurium and endoeurium)
Epithalamus upon the inner chamber region of the diencephalons
above the thalamus includes the pineal body
Extradural space space external to the Dura mater but w/n the skull or
boney canal of the SC
Extrapyramidal system all the motor parts of the CNS except thepyramidal system
Extrastriate visual areas of the CC assoc with higher order visual
recognition eg face recognition
Falx sickleas in falx cerebri, falx cerebelli
Fascis bundle
Fasciculus small bundle used for a bundle of N fibres
Fastigial gabled roof top eg the Fastigial nucleus at the top ofthe cerebellum
Fimbria fringe band of N fibres along the edge of Hp
continues as the fornix
Forceps paired tongs as in the U shaped fibres of the Corpus
Callosum - Forceps frontalis and Forceps occipitalis
Foramen a natural hole in a bone usually for the transmission of
BVs &/or nerves.(pl. foramina).
Fornix an arch as in the efferent N tract of the Hp which
arches over the Thalamus and teminates in the
Mammillary body
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Fovea pit as in the Fovea Centralis at the centre of the retina
Funiculus little cord as in the cords of WM in the SC which
consist of a number of different fasiculi all running
together in the Lateral Funiculus of the SC
Funis cordGanglion knot- collection of N cell bodies outside the SC (also
incorrectly used for isolated islands of N cells w/n in
the WM of the brain eg Basal Ganglia of the brain - see
Basal Ganglion), pl ganglia an abnormal collection of
neural tissue found subcutaneously
Gemmule small bud swellings on the ends of some dendrites
in the CNS
Genu knee anterior end of the Corpus Callosum = the
genu of the Corpus Callosum; geniculate ganglion of
the Facial N; geniculate nuclei of the Thalamus
Glia / Glial cells glueassociated supporting cells of the CNS connective
tissue and immune functions, types: astrocytes,
oligodendrocytes, ependymal cells and microglia
Globus pallidus pale ball medial part of the Lentiform nucleus of the
Corpus Striatum - part of the basal ganglia
Glomerulus small knot, tangle synaptic glomeruli of the
olfactory bulb
Grey Matter (AS Gray) N tissue in the brain and SC which contains mainly N
cells, dendrites unmyleinated axons & glial cells
(opposite to WM which contains mainly
myelinated axons)
Gracilis slender Fasiculus Gracilis of the SC; Nucleus Gracilis
of the of the Medulla
Groove long pit or furrow
Gyrus a circle, hence a coil of brain cortex generally the CC.
Hemiplegia half stroke paralysis down one side of the body
Hippocampus sea horse a neural gyrus in the Limbic system (in theTemporal lobe) producing an elevation on the floor of the
temporal horn of the lateral Ven. - involved in the
conversion of short term memory to long term memory
Homunculus little human -any representation of a human being, in
this context - the homunculus maps of the motor and
somatosensory cortex show how many neurons are
devoted to various regions of the bodyHorn projection of GM in the SC (ant. & post. horns are for
motor & sensory Ns respectively)
Hydrocephalus water in the head swelling in the cranium due to
CSF accumulation
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Hypothalamus under the inner chamber region in the Diencephalon
which controls the ANS and the Pituitary gland
Impulse a depolarization of the N membrane resulting in the
promulgation of a signal along the N process.
Inferotemporal cortex lower part of the Temporal lobe involved in numberand object recognition
Infundibulum funnel / stem stalk of the ant. pituitary =
neurohypophysis
Insula island CC concealed from the surface at the bottom
of the Lateral Sulcus = Island of Reil
Inter between
Interneurons act b/n motor and sensory Ns in a reflex - transferring
the signal from the sensory to the motor w/o higher imput
Intra within
Introitus an orifice or point of entry to a cavity or space.
Ipsi- same as opposed to contra- opposite
Ipsilateral on the same sideas opposed to contralateral
Isocortex equal bark the CC which has 6 layers = neocortexKinesthesia movement sensation the perception of moving
and movement
Lacerum something lacerated, mangled or torn- eg Foramen
Lacerum, small sharp hole at the base of the skull
often ripping tissue in trauma.
Lacrimal related to tears and tear drops. (noun lacrima)
Lateral sulcus groove running across the cerebrum in the coronal
plane separating the frontal & parietal lobes
Lambda from the Greek letter a capital 'L' and written as an
inverted V.(adj. lambdoid) and used to name the point
of connection between the 3 skull bones Occipital
and Temporals.
Lamina a plate- the lamina of the vertebra is a plate of bone
connecting the vertical and transverse spines (pl. laminae)
Leminiscus ribbon-ribbonlike, flat band of N fibres in the CNS -
e.g. Lateral & Medial Leminisci
Lentiform lenslike Lentiform nucleus of the Corpus Striatum
Limbic System group of brain structures to regulate emotion
and memory
Limbus border as in the Limbic System which has a borderof CC on the medical surface of the CH consisting of:
septal areas, cingulate and parahippocampl gyri,
mammillary bodies and ant. thalamic nuclei
Linea a line- as in the Nuchal lines of the Occitipum
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Locus a place-c.f. location, locate, dislocate.
Longitudinal sulcus deep sulcus or groove along the mid-sagittal plane of
the brain separating the R & L CH
Macula spot as in the Macula Lutea of the retina = yellow spot
Magnetic Resonance Imaging = MRI used to see soft tissues other formsare fMRI which allows for images of soft tissues as
they change see MRI
Magnum large pl magna
Mammillary -
AS Mamillary little nipple mammillary body in the ventral
surface of the Thalamus
Medulla marrow middle Medulla Oblongata the caudal
portion of the brain stem , spinal medulla
Meninges coverings of the brain and SC made up of 3 layers -
Dura (hard) mater on the outer to protect the NT;
Arachnoid (spidery) mater in the middle to support the
BS and Pia (soft) mater, the inner coating to coat the
NT and act as a barrier to foreign substances. CSF
flows b/n the inner 2 coverings.
Macroglia large supportive cells of the CNS (see Glia)
Microglia phagocytic cells of the CNS (see Glia)
Miosis excessive contraction of the pupil due to drugs or disease
Mixed N a N containing both sensory & motor components,
most peripheral Ns are mixed
Mnemonic memoryMotor / motor N causes muscle contraction. these Ns are efferentor
moving away from the SC
Motor cortex part of the brain cerebral motor cortex - responsible
for executing bodily movements
Motor program a sequence of muscle contractions needed for a
complex movement
MRI technique to see images of soft tissues eg. the brainusing magnets
Multipolar referring to a N which has many dendrites + 1 axon
(see unipolar, bipolar)
Myelin marrow- the phospholipids produced by Schwann
cells to insulate the axons of PNs and allow impulses
to travel for longer and faster to the target organ
Myotome the muscular innervation of a SN
Nerve (N) N cell (neuron) capable of transmitting or firing off a
signal caused by ion transfer - excitable cell N process
- generally Axon carrying the impulse to the skeletal
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muscle site general term meaning either the neuron(s),
process(es) or part of a bundle of neurons, either
cranial, spinal or peripheral
Neurilemma layers of Schwan cell membranes coating axon
processesNeurium general term for the CT covering of a PN fibre
(see endoneurium, perineurium and epineurium)
Neurocranium refers only to the braincase of the skull.
Neuroglia see Glia
Neuron Nerve cell
Neurotransmitter substances in vacuoles at the foot of the nerve
process which are released to induce a N impulses or
in response to a N impulse
Nociceptive injury nociceptors respond to injurious stimuli
Nucha The nape or back of the neckadj.- nuchal
Nystagmus sleepy involuntary oscillations of the eyes
Occiput The prominent convexity of the back of the head
Occipitum = Occipital bone adj. occipitalOligodendrocytes in the CNS only, become Schwann cells in the PNS and
SC, act as a barrier and insulator of axons and neurons
Osmatic to do with the sense of smell
Pars a part of
Pathway general term indicating a path of defined N fibres
Perineurium middle of the 3 CT coverings of a PN fibre
(see neurium, perineurium and epineurium)
Peripheral N (PN) coming from the SC, - often the combination of 1 or
more SNs or part thereof and not the brain directly
(cranial N) see Spinal N
Peroneal pertaining to the lower leg
Pia soft pia mater PM soft covering of the brain
Pineal pine cone shaped pineal body = pineal glandPlexus plait / knot an interlaced network of Ns
brachial plexus
Polarization the maintenance of an unequal charge across the
membrane of the N, allowing the cell to be stimulated
- all excitable cells have a polarized membrane
Pons bridge part of the brainstem which lies b/n the
medull and the midbrainPosterior - part of the CC which transforms visual information
Parietal cortex into motor commands
Precentral gyrus site of the primary motor cortex
Prefrontal cortex involved in complex decision making, behavioural
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inhibition and judgement
Premotor cortex involved in sensory guidance of movement
Primary motor cortex area directly involved in producing muscle contraction
Primary visual cortex receives the first visual information = Brodmanns
area 17, V1 see Striate cortex
Procedural memory unconscious memory such as recall to catch a ball
Process A general term describing any marked projection or
prominence as in the mandibular process, in
neurology the nerve process either Dendrite or Axon
depending upon the direction of the NI.
Projection fibres axons which connect the Cerebral cortex with the
Brainstem or SC
Proprioception sense of position of body parts
Prosencephalon = forebrain
Proximal closer to the axial skeleton (opposite of distal)
Ptosis drooping- describing a dropping upper eyelid
Pulvinar a cushioned seat posterior projection of the Thalamus
over the medial and lateral geniculate bodiesPutamen shell larger lateral part of the lentiform nucleus
one of the basal ganglia
Pure N a N which is either only sensory or motor not both
(as in mixed N)
Pyramidal system corticospinal and corticobulbar tracts which form a
pyramid shape on the ventral surface of the MO
Pyramidal tract corticospinal tract only
Pyriform pear shaped pyriform area of the olfactory cortex
Quadriplegia = Tetraplegia, paralysis of all 4 limbs
Ramus branch pl. rami/branches- 2 main branches Ventral
supplying all structures in front of the SC and Dorsal
| supplying all structures behind the SC - the Rami are
mixed NsRaphe seam an anatomical seam in the midline raphe
nuclei of the reticular formation, in midline of the MO,
Pons & MB
Reflex referring to the Reflex arc of sensory impulse - going
to the SC and causing a motor or efferent response
w/o imput from the brain
Refractory period time b/n depolarization and repolarization, where theN cannot be restimulated in part to stop the impulse
from traveling in both directions
Repolarization restoration of the resting potential after transmission
of a N impulse (see depolarization, polarization)
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Resting potential the charge difference across the cell membrane of the
N created by ionic imbalance
Reticular a net as in the reticular formation of the brainstem
Rhinal pertaining to the nose
Rhinencephalon part of the components of the olfactory system
Ridge Elevated bony growth often roughened.
Root the segment(s) of origin of the PN from the SN
Rostral towards the nose
Rostrum beak recurved process of the Corpus Callosum
Rubro redas in the red nucleus rubrospinal tract
Saccadic to jerk as in quick jerky movements of the eyeswhen changing focus
Sagittal an arrow, the sagittal suture is notched posteriorly,
making it look like an arrow by the lambdoid sutures;
the anatomical plane from anterior to posterior.
Satellite attendant satellite cells form a capsule around Ns
in ganglia
Schwann cells cells supplying phospholipid coat - insulation to theaxons to preserve the N impulse in the PNS - role of
the oligodendrocytes in the CNS
Secondary -
visual cortex = V2 perceives colour and form
Sensory to feelpertaining to imput - which goes to the SC and
then brain &/or reflex
Short term memory that memory limited to several minutes of recall only
Soma body- the main part of the neuron
Somatic bodily denotes the viscera in neurology
Somatosensory relating to information perveived through sensory
receptors in the skin and muscles
Spinal Cord (SC) Extension of the brain protected by the VC, PN
come from hereSpinal Nerve (SN) N coming directly from the SC not the brain
Spine a thorn (adj. spinous)descriptive of a sharp,
slender process/protrusion.
Splanchocranium the splanchocranium refers to the facial bones of the skull
Splenium bandage thickened post. extremity of the
Corpus Callosum
Stimulation events which lead to the formation of a N impulse
Stimulus something in the environment which will cause a N
impulse to be generated from the receptor
Strabismus a squinting constant lack of parallelism in the visual
axes ie crossed eye(s)
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Stratum layer as in stratum zonal on the dorsal surface of
the Thalamus
Striate striped
Striate cortex striped rind = Brodmanns area 17
= primary visual cortex
= V1;
CC on the Occipital lobe which receives 1s visual
information from the eyes via the Thalamus (has a
white stripe w/in the cellular layer)
Subcortical anything deep to or beneath the CC
Subdural space space beneath the DM external to the AM
Subiculum little layer- as in the thin layer of GM b/n Hp and
parahippocampal gyrus
Substantia gelatinosa a column of GM at the apex of the dorsal horn of the SC
Substantia nigra dark substance- large nucleus in the MB with a high
number of pigmented cells loss of cells in this area is
related to Parkinsons disease
Sulcus long wide groove often due to a BV indentation spaceb/n the gyri of the GM in the brain (pl sulci)
Superior temporal gyrus refines language interpretation such as
recognizing s as a plural etc
Supplementary motor area = SMA involved in complex motor functions such
as 2 handed functions
Supramarginal gyrus forms words form letters
Sural pertaining to the lower leg
Suture The saw-like edge of a cranial bone that serves as
joint between bones of the skull.
Synapse to join- the gap at the joining of N and nerve process,
N and N, process to process or N and muscle for trans-
mission or inhibition of an impulse via neurotransmitters
- presynaptic before the synapse (where the
neurotransmitter is released) / post synaptic after thesynapse (where the neurotransmitter is received).
Tapetum carpet fibres from the corpus callosum over the
lateral wall of the lat. Ven.
Tectum roof as in the roof of the MB
Tegmentum cover dorsal portion of the Pons
Tela choroidea web membrane vascular CT continuous with the PMwhich continues to the Choroid plexus
Telodendria axon terminal branches
Temporal refers to time and the fact that grey hair (marking the
passage of time) often appears first at the site of the
temporal bone.
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Tetraplegia see Quadriplegia
Thalamus inner chamber functions are sensory and integrative
2 egg-shaped masses of Ns key relay station and
filter of information to go to and not to go to the CC
Tract vertical columns of axons, generally myelinated in theSC &/or brain
Tractotomy see Cordotomy
Trunk when SNs join together as large combined large Ns to
supply specific anatomical regions (e.g. BP) but again
must re-organize to become PNs
Uncus hook adj. Uncinate -
Uvula little grape as in dorsal part of the cerebellum
Vallecula little valley as in the fold on the inferior aspect of
the cerebellum
Velate sail
Ventral chest- to the front, used interchangeably with
anterior, relating to the chest
Ventricle little belly as in ventricles of the brain filled with CSFVermis worm as in the vermis of the cerebellum
midline structure
Wernickes area located in the Temporal lobe crucial for language
and comprehension
White matter N tissue which consists mainly of myelinated axons
(see Grey matter)
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Guide to Anatomical Planes and Relations
This is the anatomical position.
A= Anterior Aspect from the front Posterior Aspect from the backused interchangeably with ventral and dorsal respectively
B= Lateral Aspect from either side
C= Transverse / Horizontal plane
D= Midsagittal plane = Median plane; trunk moving away from this
plane = lateral flexion or lateral movement moving into this plane
medial movement; limbs moving away from this direction =
abduction; limbs moving closer to this plane = adduction
E = Coronal plane
F = Median
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Anatomical Movements
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Hip flexion Hip extension
Hip abduction Hip adduction
Hip lateral andmedial rotation Hip circumduction
Knee flexion Knee extension
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Foot dorsiflexion Foot plantar flexion
Foot inversion
Fingers extension
Forearm pronation
Fingers abduction Thumb opposition
Fingers flexion
Forearm supination
Fingers adduction
Foot eversion
Foot normal position
Hand deviationradial/laterallyulna/medially
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The Nervous system
The nervous system is made up of: the CNS = Brain + SC, the PNS =
Ns exiting from the CNS - CRANIAL directly from the brain (12 PAIRS)
and from the SC (31 PAIRS), the protective coverings of the tissue aremade up of - connective tissue - the MENINGES of which there are 3
layers, the outer or DURA MATER and the inner often fused 2 layers
THE ARACHNOID & PIA MATERS for the diffusions of CSF and blood
around the Brain and SC, and boney coverings, the Skull around the
brain and the vertebral column (VC) around the SC.
In the PNS the Ns form 2 separate divisions the voluntary and theautonomic (ANS). The ANS is made up of the Sympathetic exiting from
the thoracic region and Parasympathetic Ns, depending upon the
region of the SC, and these nerves may travel with the PNs.
THE NERVOUS SYSTEM
A. L. Neill28
SPINAL
CORD = SC
CENTRAL NERVOUS
SYSTEM = CNSPERIPHERAL NERVOUS
SYSTEM = PNS
BRAINBONEY = SKULL
CONNECTIVE
TISSUE
= MENINGES
PROTECTIVE
COVERINGS
BONEY = VC
CONNECTIVE
TISSUE
= MENINGES
CRANIAL
NERVES (1-12)
SPINALNERVES = SNs
ANS
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This brain is stripped of its normal meningeal
coverings, showing cerebral cortex - grey matter.
A = superior view
B = L lateral view
C = R lateral view
D = inferior view
E = sagittal view
A
B
D E
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The Nerve Cells
The basic functioning cell of the NS is the NEURON = NERVE CELL =
N. Most are multipolar meaning that they have multiple dendritic (2)
processes, which feed impulses into the nerve cell body (7). All Ns onlyhave one axon (6), taking an impulse away from the cell body.
There are 2 basic types of Ns: - MOTOR Ns, which stimulate target organs
and SENSORY Ns, which provide feedback about the target organs.
Nerve cells when grouped together have a grey appearance and when
seen in large collections are called GREY MATTER = GM, while their
processes are often myelinated and appear white so neural tracts are
called WHITE MATTER = WM.
In the brain the Ns are on the surface or cortex, except for some areas
where collections of Ns may be seen deep in the brain tissue nuclei (or
ganglia). In the SC, the Ns are placed deep in the tissue in long columns.
1 nucleus and nucleolus2 dendrites
3 neurilemma - protective myelin sheath from Schwann cells
4 axon terminal branches / telodendria
5 nodes of Ranvier
6 axon and base of axon - axon hillock
7 N cell body plasma with neurofibrils, Nissl bodies,
mitochondria, Golgi & ribosomes
8 presynaptic membrane
9 synaptic vesicles
10 neurotransmitter
11 synaptic cleft
12 postsynaptic membrane on dendrite or N cell body
13 myofibril of skeletal muscle
14 sarcolemma - cell membrane
of the skeletal muscle cell
15 sarcoplasm - plasma of theskeletal muscle cell
16 subneural clefts
17 mitochondria
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15 16
4
13
14
3
17
4
18
5
6
7
1
2
4
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9
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7
12
10
13, 14
3 4
2
1
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Blood Brain Barrier BBB
Schema of Blood Vessel
BBB in the neuroaxis of capillaryBBB in the choroid plexus in ventricle
The Blood Brain Barrier BBB prevents brain tissue from being
exposed to various blood borne substances. This is achieved by a
number of factors: the glial foot processes on capillaries , the unique
properties of the endothelial lining and components of the basement
membrane. The filter also alters the components of the CSF fluid viathe vessels in the choroid plexus and the choroid epithelium.
Clinically this may prevent the neural tissue from the effects of oral and
iv medications and toxins, requiring intrathecal injections. In certain
pathologies particularly inflammatory ones the barrier can be
compromised, causing oedema and other complications.
1 Medium sized cerebral BV
2 Pia Mater layer
3 Glia limiting membrane
4 Perivascular space
5 Foot processes of astroglia on capillaries6 Neural tissue
7 BV lumen
8 Endothelial cell f = fenestration
9 Basement membrane
10 Glial tissue
11 Choroid epithelium
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1
3 2 4 5
7
6
5
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8
7
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910
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Blood Supply overview
Brain Schema of the brain coronal
1 Skull = boney covering
2 Meningeal vein
3 DM around the venous sinuses + communicating vessel
4 External cerebral vein
5 Brain nervous tissue
6 Choroid plexus
7 Deep cerebral vein
8 Extracranial vein
9 Extracranial artery
10 Meningeal artery
11 Superficial cerebral artery
Spinal Cord Schema of the SC transverse
1 Posterior spinal artery
2 Radicular branches a = anterior / L = lateral / p = posterior
3 Arterial vasocorona
4 Lateral artery5 Anterior radicular artery
6 Branches of the superficial arterial network
7 Anterior spinal artery
8 Sucal artery = ant. spinal art. (lies in the sulcus of the SC)
9 Marginal zone (of Lissauer) - ALM tracts before synapse
10 Anterior horn = ventral motor horn
11 Deep spinal artery
12 Substantia gelatinosa - ALM Ns synapse point
13 Mediobasal column (of Clarke) - for sensory interneurons
14 Posterior horn = dorsal sensory horn
15 Skull = boney covering
16 Meningeal vein
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1
2
3 4
5
6
7
89
10
11
12
9
12 13 14 2p1
2L
4
3
5
6
2a9
1011
8
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Blood Supply overview
Spinal Cord
Schema of the SC anterior surfaceC = cerebral region
T= thoracic region
L= lumbar region
1 Basilar artery
2 Vertebral artery3 Radial artery of C5
4 Radial artery of C7
5 Anterior spinal artery
6 Lateral thoracic arteries
7 Artery of the lumbar enlargement
Expanded on the one side at the level of T10 L2
Spinal Cord
Schema of the SC deep and superficial arterial networksNote there are minimal anastomoses b/n these 2 different circulations
This circulation as with the brain has end arteries and distally the
tissue may be compromised.
A deep arterial network neural tissue supplied by anterior spinal artery
B superficial arterial network
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T1
T
T12
7
5
4
3
2
1
6
L
C
A B
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CEREBROSPINAL FLUID = CSF - circulation of
fluid in and around the Brain & SC
Lateral overview of ventriclesSagittal view of CSF circulation
Definition CSF bathes the Brain and SC, filtered from arterial blood by the
Choroid plexus (27). Removing the blood proteins and cellular elements, it
circulates through the ventricular system and subarachnoid space of the
brain and SC and then is removed by the Arachnoid granulations (20) to
the venous sinus systems around the brain. Blood in the perforating BVs(21) surrounding the neural tissue is also filtered via the BBB.
THE BRAIN
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1 Frontal lobe
2 Anterior horn of lateral
ventricles
3 Body of the lateral
ventricles -
4 Cerebral cortex
5 Parietal lobe
6 Posterior horn of the
lateral ventricles
7 Occipital lobe
8 Cerebellum
9 Cerebral aqueduct
(aqueduct of Sylvius)
10 4th ventricle with
lateral aperture
11 Median aperture
(foramen of Magendie)
12 SC
13 Lateral recess of
4th ventricle
(foramen of Lushka)
14 Pons
15 Temporal lobe
16 3rd ventricle
17 Lateral fissure
(Sylvian fissure)
18 Interventricular foramen
19 Subarachnoid space
20 Arachnoid granulations
21 Perforating veins
22 Pia/arachnoid mater
23 Transverse sinus
24 Cistern of the great
cerebral vein*25 Cerebral artery
26 Cerebral vein
27 Choroid plexus
28 Pituitary gland + stalk
29 Dura mater
30 Superior sagittal sinus
*may sample CSF here
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1
18
17
1615
1413
1211
109
8
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2
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27
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25
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The Brain develops from
ectoderm the top
germinal layer cellsform a tube the neural
tube which develops 3
bulges as shown and
develop into the
CNS. Additional
cells excluded fromthe tube become the
neural crest and form
the components of the
PNS.
The brain continues to
develop throughoutadolescence and may do
so throughout life,
although neural tissue
has a limited capacity to
repair.
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Brain Development and Organization
foramen magnum
(exit from skull)
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PRIMARY SECONDARY DERIVATIVES
BRAIN VESICLES BRAIN VESICLES
Cerebral Cortex
Basal NucleiTelencephalon
Diencephalon
Metencephalon
Myelencephalon
Spinal cord
Midbrain
Superior colliculus
Pons
Cerebellum
Medulla Oblongata
dorsal horn = sensory
ventral horn = motor
Retina of the eyeThalamusHypothalamus
Neurohypophysis
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The Brain and SC macroscopic structure
The Brain places most of its neurons on the outer surface cortex -
which gives the brain surface a grey colour hence it is the grey matter
GM. The Ns are connected by their processes underneath mostlymyelinated and hence white coloured fibre tracts the white matter WM.
The Ns of the brain are layed down in multiple laminae/layers in
particular patterns which can be recognized and identified histologically
with the NISSL stain. Particular cytoarchitechtural patterns have thus
been identified and regionalized the commonest scheme being the
BRODMANN mapping of the CC.
In many cases the structure has been found to relate to the function of
these areas and so as well as naming the structure, a Brodmann
number may also be listed. The Brodmann area is related to the
arrangement of the Ns in the region but this may not always be directly
related to the macroscopic appearance of the brain.
The SC has its nerve cells on the inside, which are in long columns 2 in
the front ventral horns and 2 in the back dorsal horns.
Connecting processes b/n the SC and the brain run up and down the
SC outside the GM forming tracts of WM, and neurons are also found
posteriorly sitting outside the main mass of the SC in small groups at
each outlet dorsal root ganglia.
1 GM b = basal ganglia- deep GM - part of the Corpus
Striatum / c = cerebrum / k = cerebellum / s = SC
2 WM c = cerebrum / k = cerebellum / s = SC
3 Space in the CNS filled with CSF in the c = cerebrum
k = cerebellum s = SC (spinal canal)
4 Subarachnoid space
5 Sagittal sinus s = superior / i = inferior
6 Lateral ventricle
7 Third ventricle
8 Cerebral aqueduct9 Fourth ventricle
10 DM
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11 AM
12 PM13 Choroid plexus
14 Arachnoid granulations
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2C145S5i
4C6
7
8
3K
4
9
4
10
11
12
2S
1S
1S
2K3S
1K
1B
13
3C
1C
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The Brain fibrous tracts
coronal- view looking at the face
sagittal view looking from the sideThe Brain places most of its neurons on the outer surface cortex -
which gives the brain surface a grey colour hence it is the grey matter
GM. The Ns are connected by their processes underneath mostly
myelinated and hence white coloured fibre tracts the white matter WM.
The fibrous tracts of the WM in the brain are of several types
Association fibres = N tracts connecting one area to another of the
same specialty of increasing complexity e.g. area primary visual cortex
V1 to the secondary visual area V2 e.g. the perpendicular and uncinate
fasciculi and the short fibres
Commissural fibres = N tracts which cross from one side to the other
in the cerebrum the largest of these is the Corpus Callosum (+ ant. &
post. commissures)
Projection fibres = N tracts which send fibres of one modality to an
area of an other i.e. from the visual areas to the frontal areas for
decision making processes to begin based on the visual information
e.g. superior & inf. longitudinal fasciculi.
1 GM of the cerebrum = cerebral cortex2 Association fibres of the cerebrum WM short fibres
3 Commissural fibres of the cerebrum - WM (Corpus Callosum)
4 Projection fibres of the cerebrum - WM4i inferior longitudinal fasciculus /
4s superior longitudinal fasciculus5 Gyrus
6 Sulcus
7 Longitudinal fissure
8 Lateral fissure / sulcus
9 Insula GM of cerebrum deep to the lateral fissure10 Thalamus
11 uncinate fasciculus
12 perpendicular fasciculus
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10
7
3
6
5
4
9
8
21
3
12 4i5
11
14S
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Dura Mater - DM = Hard Mother
Outer layer of the Meninges
Fixes the brain and limits movements supports the 2 inner coverings
which contain the BS of the Brain.
Continues down the SC to protect the neural tissue in this region as well.
Composed of thick connective tissue
Space b/n Skull and DM = EXTRADURAL SPACE (hence extra-dural
haemorrhage)
Space b/n DM and Pia Arachnoid maters = SUBDURAL SPACE
(hence sub-dural haemorrhage)
The DM is pain sensitive and may be the cause of local headache or
spinal pain or referred pain to structures associated with the exiting Ns.
1 Falx Cerebri contains and prevents movement of the main
cerebral hemispheres supports the superior sagittal sinus
2 Tentorium Cerebelli separates the Cerebrum and the
Cerebellum forming a roof over the cerebellum - supports
the straight and transverse sinuses
3 Dura Mater covering the SC lumbar region
4 Zygapophyseal jt
5 Spinous process
6 Intervertebral disc
7 PLL (at the back of the VB)
8 Sinuvertebral N9 SN
10 Sinuvertebral artery
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The Meninges and the Brain
1 Bone - Skull
2 Frontal sinus
3 DM
4 AM + Subarachnoid space
5 PM
6 SC
7 Dural sac of the SC (continuing on from the cranial cavity)8 Subarachnoid space (b/n Cerebrum and Cerebellum)
9 CC GM
10 Corpus Callosum
11 WM of the brain
12 Sagittal sinus i = inferior / s = superior
13 Falx cerebri
14 Arachnoid granulations
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The Meninges and the Spinal Cord (SC)
Transverse view of the SC and coverings cross-section
Coronal view cutting down the VC showing the SC andcoverings.
1 SN
2 Nerve root (mixed N)
d = dorsal root (pure sensory)
v = ventral root (pure motor)
3 Denticulate lig. (from the PM)
4 DM
5 Outer layer of the AM
6 Subarachnoid space (b/n the intermediate layers of
the AM)7 Dorsal lig (from the AM)
8 PM
9 SC GM
d = dorsal horn
v = ventral horn10 Central canal
11 Filum terminale (PM)
12 Thoracic enlargement of the SC
13 Lumbar enlargement of the SC
14 SC termination at L1/2 in adults15 Spinal canal termination at S2
16 Anterior spinal artery
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Neurological Assessment HEADACHE
DEFINITION: pain or discomfort b/n the orbits and Occiput
arising from pain sensitive structures via
Extracranial pain sensitive structures:
The ear inner & middle - also refers pain to C2 (2)
The eye orbit - also refers pain to C2/3 (3)
The mouth teeth & gums also refers pain to C4 (4)
The nose - nasal mucosa, paranasal spaces also refers pain to C3 (3)
The scalp BVs & muscles also refers pain to C1 (1)
Intracranial pain sensitive structures :
Basal arteries
Cortical veins & venous sinuses
DM of the ACF and MCF innervated by CN V1 (5) pain also referred
to the forehead and temple & PCF - innervated by CN IX, X (6) pain
also referred to the back of the head and neck (suboccipital and upper
cervical regions)
Note other structures e.g. the cervical VB and neck muscles may refer
pain to the head and cause a headache
HISTORY:
Associated features visual disturbances, vomiting + other
Character aching dull / sharp, throbbing stabbing
Duration & timing hours / days / morning / evening
Frequency acute single, chronic daily / wkly / mnthly
intermittent - seasonal
Mode of onset gradual, rapidPrecipitating factors coughing / exercising, hunger,
medications / foods, menstruation / menopause
noise / stress, posture changes / stooping
Relieving factors analgesics, lying down / sleeping
Severity scale 1-5, bearable able to read / unbearable
unable to do anything
Site front / band around the head / back
specific region above the eye / around the
temple
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HEADACHE diagnoses = changes in
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pain type
consci-
ousness
progressivedeterior-
ation
Headinjury
infect-ion
onsetlimb
weak-
ness
eyemove-
ments
throbbing - - - quick - -
severethrobbing
- - - quick - +
severe - - - - quick - -
dullintermittant
- + - - slow - -
acute sharp - + - - varies - -
severe + + + - rapid
variesrecedes
- - - - quick - -
severe + + - v quick + +
severe + + ++ rapid + +
dull + + - slow + +
dullconstant
+ + - - slow
dull
constant
+ + - - slow
severethrobbing
- - - - slow - -
increasesthroughthe day
- - - - varies - -
dull - - - slow -
sharppositional
- - varies + -
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neckstiffness
visionrecurr-ence
nausea vomitting
headachelocation
other DX
++ -face
foreheadsinusitis
+ + + ++ global migraine
+ + + globalcluster
headaches
- + + - frontalhalos around
objectsglaucoma
- + - - orbitalunilateralvision loss
retrobulbarneuritis
- + globalpost-
traumatic
- - - global drugs/toxinsvasodilators
+ - ++ globalhaemorr-
hage
+ - ++ globalfocal
neurologicalsigns
meningitisencephalitis
acute /
subacute
+ - + globalimpaired
upward gazehydroce-phalus
- - + globalpapilloe-
demaintracranial
Tm
- - + globalpapilloe-
dema
benignintracranial
hypertension
+ - + - templestiff tender
scalparteries
temporalarteritis
- - ++ -frontalband
pattern
situationprecipitates
onset
tensionheadaches
- + - -need ocularaids/glasses
impairedvision
+ - + -back and
neckupper limb
paincervical
spondylosis
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NEUROLOGICAL SYMPTOMS
changes in site of control
balance CN VIII / middle ear
conscious levels global brain/ metabolic
headache global brain / DM / neck / multiple sources
hearing CN VIII middle ear
mental frontal lobe /
endocrine
motor SC / Brainstem / Cerebellum
sensory SC /sensory CC
smell CN I
speech / swallowing CN IX-XII
upper cervical Ns
sphincters / continence Sacral Ns
lumbar SCtaste CN X, XII ``
visual CN II-VI
voice change CN X
NEUROLOGICAL EXAMINATION
From head to toe
CNs see CN section
Conscious level & higher functions emotional state, memory, reasoning
MOTOR
Upper limbs
Trunk and lower limbs -Sphincters -
Examine: power, tone, symmetry, reflexes, ROM
SENSORY
Upper limbs
Trunk and lower limbs -
Examine pain, touch, pressure, proprioception, temperature
see the A to Z of Peripheral Nerves for details
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The UNCONSCIOUS PATIENT
HISTORY
Ask those around: Alcohol or drugs preceding the event ? medications ?
Illness preceding the event
Epilepsy
Sudden collapse
Head injury ?
Limb twitching
Assessment of conscious level (Glasgow coma scale)Assess EYE OPENING
NON-RESPONSIVE
AssessVERBAL RESPONSE
ORIENTATED knows where they are
CONFUSED talks in sentences
WORDS cannot form sentences but
can form words
SOUNDS can only make sounds
NONE no response to questions
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SPONTANEOUS TO SPEECH TO PAIN via pressure
to the supraorbital N
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LOCALISING
MOVEMENT TOWARDS
PAIN directional
response to pain
OBEYS COMMANDS
EXTENDING TO PAINextension of the elbow &
spastic flexion of the
wrist non-directional
Record assessments as 1-5 for each modalityAlways record the best result if there is variation
Always record the upper limb result as this is more consistent
FLEXING TO PAIN
elbow flexing but no movement
towards pain
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type areaaffected
ability to
repeat
speech
auditory
comprehensionfluency
Brocas =expressive
aphasia
frontalcortex
++++ +++++ nonfluent labouredspeech, slow disjointed
sentences agrammatism
Wernickes*= sensoryaphasia =
receptiveaphasia
sup. temporalgyrus of thedominant CH
+ - but can learnand sing songscorrectly (fromthe non. dom.CH)
fluent - nonsensicaljargon paraphasic(substituting wordswhich sounds the same)poor self correction
Conduction =associativedysphasia
arcuatefasciculusconnectingBrocas toWernickesarea
+ ++++ often the result of astroke, fluent paraphasicbut with self correction
mixedtranscortical
++ + non-fluent
transcorticalmotor
++ ++++ non-fluent
transcorticalsensory
supramarginal + angulargyri
+++++ + fluent self correction ofgrammar + syntax only
global + + non-fluent
anomic =amnesicdysphasia
global -parietal +temporallobes & theirconnections
++ +++++ often the result of headinjury or tumour, fluent circumlocution becausecannot recall the names ofthings
APHASIA
acquired deficiency in language processing incorporating
both production and comprehension, due to brain damage.
* note is not Wernickes encephalopathy
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Blood Vessels and the Meningeal layers
of the Brain
1 scalp vein
2 scalp skin covering
the skull
3 middle meningeal vessels
a=anterior / m=middle /
p=posterior branches
4 Frontal bone
5 dura mater e= endostial /
m= meningeal layers
6 Parietal bone
7 transverse sinus (R/L)
8 Occipital bone
9 superior sagittal sinus /
v= venous lacuna
10 arachnoid granulations
11 emmisary veins12 cerebral veins s=superior
/sp=superficial branches
13 arachnoid mater p with
pia mater (often fused)
14 cerebellum15 diploic vein
16 frontal sinus
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9v10 11 1 2 3p
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Venous sinuses the Meningeal layers
of the Brain
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1 scalp vein
2 scalp skin covering
the skull
3 middle meningeal vessels
a=anterior /m=middle
/ p = posterior branches
4 Frontal bone
5 DM e = endostial /
m = meningeal layers
6 Parietal bone
7 transverse sinus (R/L)
8 Occipital bone
9 superior sagittal sinus /
v = venous lacuna
10 arachnoid granulations
11 emmisary veins12 cerebral veins s=superior
/sp=superficial branches
13 arachnoid mater with pia
mater (often fused)
14 cerebellum15 diploic vein
16 frontal sinus
17 cerebrum
postcentral gyrus
18 falx cerebri19 olfactory bulb and tract
20 optic chiasma
21 carotid artery
22 sphenoparietal sinus
23 hypophysis and stalk
(infundibulum)
24 CNs 24-3 CN III /24-6CN VI / 24-4 CN IV/
24-5 CN V
25 petrosal sinus
s=superior/ i=inferior
26 straight sinus
27 tentorum cerebelli
e=edge inserted b/n
cerebrum & cerebellum
28 great cerebral vein
29 basilar plexus
30 dorsum sella
(DM removed)
31 cavernous sinus
32 orbital plate
(of the frontal bone) ACF
33 crista galli
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1920
21
22
2324-324-624-4
24-5
25s25i
7R
27
926
28
27e
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29
30
31
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9
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3p
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Brain arteries - Overview
The brain is an end organ in that once past a central anastomotic ring
of vessels, the circle of Willis all supply to the distal tissue is a single
supply. Any blockage of the BV distal to that arterial circle will die,making the Brain a great energy consumer sensitive to any regional
deprivation of blood. Overall the brain as a whole cannot be deprived of
arterial blood for longer than 10 sec to any partic. area - 20% of the
CO goes to the brain brain is 2.5kg or
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The Veins and Venous drainage of the
BRAIN Overview
On the surface of the brain there are many BVs which drain into aseries of sinuses endothelial lined channels b/n the 2 layers of the
DM. They anastomose extensively and have no valves relying on
gravity, cranial pressure and head movements for drainage. Superficial
vessels drain to the superior sagittal sinus (1s) and deeper vessels
drain to the straight sinus (4). The eyeball and facial areas drain to the
cavernous sinus (8) and may bring infection into the cranial cavity.
1 Sagittal sinus i=inferior / s = superior
2 Connecting anastomosing veins
3 Deep posterior cerebral veins
4 Straight sinus
5 Transverse sinus6 Sigmoid sinus (s-shaped)
7 Petrosal sinus i =inferior / s = superior
8 Cavernous sinus
9 Internal jugular vein
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Cranial Venous Sinuses
The venous supply of the brain consists of a number of sinuses - or
lakes of blood protected from the brain tissue by the DM. Unlike other
veins in the body, they have no muscle or valves in their walls.Arachnoid granulations feed CSF into this system, which then drains to
the jugular veins. Flow is determined by pressure w/in the cranial cavity
a closed box. CSF, gravity and arterial pressure affect this and flow
may be very slow and on occasions is bidirectional.
Cavernous Sinus
Coronal section, Looking into the sinus posteriorly
One of the most complex sinuses is the Cavernous sinus. Through this
lake of slow moving venous blood, air, arteries, brain and glandular
tissue and CNs traverse, making this site particularly dangerous for
infection and/or neoplastic spread.
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1 pituitary gland =hypophysis
1a anterior lobe
1i infundibulum = stalk
1p posterior lobe
2 third ventricle3 Optic N = CNII
3c chiasma
3n nerve
4 cerebral arteries branches
4a anterior4m middle
4p posterior
5 internal carotid artery
6 communicating arteries
6a anterior6p posterior
7 Occulomotor N = CN III
8 Trochlear N = CN IV
9 Trigeminal N =CN V
9-1CN V1
9-2CN V2
10 foramen ovale
11 Abducens N = CN VI
12 internal carotid artery13 carotid sympathetic
nerve plexus
14 opening to nasal cavity
15 sphenoidal air sinuses
16 body of the sphenoid
17 DM dura matere = endostial layerm = meningeal layer
18 cavernous sinus =filled with venous blood
19 cerebral cortex
20 AM -arachnoid mater
21 subarachnoid space
22 PM = pia mater
23 diaphragma sella
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17M
20 2
122
1
a
1p
23
3n
1
2
4a
5
4m
9345
i
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6
10
12
11
14
15
16
13
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17m
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Sagittal venous sinuses
Superior and Inferior
Superio-laterallooking into the head from above and laterally
1 CNs 1-3 CN III /1-6CNVI / 1-4 CNIV/ 1-5 CNV
2 emmisary vein
3 scalp skin covering the skull
4 DM e= endostial / m = meningeal layers5 sagittal sinus / s = superior / i = inferior
6 falx cerebri
7 hypophysis i = infundibulum (stalk)
8 crista galli
9 petrosal sinus s = superior/ i = inferior10 tentorum cerebelli e=edge
11 transverse sinus
12 straight sinus
13 great cerebral vein
14 cerebral artery a=anterior /m= middle /p= posterior branches
15 communicating artery a = anterior /p = posterior branches
16 internal carotid artery
17 frontal air sinus18 trigeminal ganglion (from CNV)
19 middle meningeal vessels a = anterior /m = middle /p = posterior branches
20 greater superficial petrosal N
21 cerebral aqueduct (aqueduct of Sylvius)22 midbrain
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CNs relationships.
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10 65i
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9s 1-41-3 3
4
1-2
1-1
7
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5s4m
4e321-51-6
1-7,8
1-9,10
13
12
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101-11 1-12
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8
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1-31-4
1-61819204m9s
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Circle of Willis = Cerebral arterial circle
Arterial vessels to supply the cerebrum arise from the inferior surface
of the brain via the internal carotid arteries which enter the cranium via
the carotid canal and the anterior surface of the SC via the Basilarartery from the fusion of the 2 Vertebral arteries. These 3 BVs form an
anastomotic arterial ring the circle of Willis - from which branches
arise to supply the cerebrum. Because of its structure, supply can be
continued despite the blockage of any 1 or 2 of the individual
contributors, provided it is not acute. However distal to the ring this is
not the case.
1 Anterior cerebral
2 Anterior communicating
3 Ophthalmic
4 Internal carotid
5 Medial striate (branches)
6 Midfdle cerebral
7 Lateral striate (branches)
8 Anterior choroid
9 Posterior communicating10 Posterior cerebral
11 Superior cerebellar
12 Posterior choroid
13 Basilar
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The Brain Macroscopic Components
The brain lies in the cranial cavity the skull - consists of the CEREBRUM,
CEREBELLUM, MIDBRAIN, and HIND BRAIN which leads to the SC.
The CEREBRUM overlies most of the brain and consists of 5 lobes
named according to the bones which they underly, see theA to Z of
the Head & Neck, and the hidden grey matter the INSULA.
B/n the brain and the skull are the meninges which act as protective
coverings, limit the movement of the brain w/n the skull, support the
BS and CSF and filter material to and from the brain. The outer GM isarranged as a series of folds to maximize the surface area: the GYRI
the convex folds and grooves SULCI (may also be called fissures),
named according to their anatomical position on the brain.
Brodmann numbers have also been assigned to these areas, particularly
on the CC which relate the grey matter to brain functions, they often span
gyri and do not directly correlate to the anatomical divisions of the brain.Generally information flows from the back of the brain primarily the
sensory areas via a series of tracts of WM nerve processes - to the
front where it is integrated and processed, resulting in decisions,
planning or other higher functions.
FRONTAL LOBE for thinking, planning, decision making & motor execution
II PARIETAL LOBE for somatosensory perception - integration of visual,
proprioceptive and spatial information.
III TEMPORAL LOBE for language, auditory perception, memory & emotion
IV OCCIPITAL LOBE for vision 1 CN V1 opthalmic division
Inferior
Lateral
Posterior
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The Brain Macroscopic Components cont
1 Frontal lobe
2 Central Sulcus = Rolandic fissure3 Parietal lobe
4 Parietal occipital sulcus
5 Occipital lobe
6 Cerebellum
7 SC coming from the Brainstem
8 Temporal lobe
9 Lateral fissure = Sylvian fissure
10 Central Sulcus = Central fissure
11 Cerebral hemisphere = CH12 Cerebellar hemisphere
13 Posterior lobe of the cerebellum
14 Vermis
15 Folia = small gyri and sulci of the cerebellum
16 Pons
17 Infundibulum (of the pituitary removed)
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1
1011
5
6
12
13
7
14
15
98
7
6
5
4
3lateral
posterior
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Cerebral gyri and sulci
Inferior view looking up at the cerebrum
Lateral looking at the side of the cerebrumMedian = Midsagittal - looking at the middle plane
The labeling of the fissures, gyri and sulci are often duplicated. The
most common duplications are listed here. Gyri can also be labeled
using a Capital letter to designate the lobe and a number to show its
position in the lobe. Sulci are labeled the same way only with a small
letter e.g. T1 = first or superior temporal gyrus the correspondingsulcus = t1. However several of these large folds may cross the lobe or
may have different names along their length.
The commonest names and duplications are listed below.
1g-5g = orbital gyri 1s-3s = orbital sulci
1g gyrus rectus, straightgyrus F4
2g medial orbital gyrus F5
3g anterior orbital gyrus F3
4g posterior orbital gyrus F3
5g lateral orbital gyrus F3
1s medial orbital sulcus f4
2s H-shaped orbital sulcus f3
3s lateral orbital sulcus f3
6f rhinal fissure (b/nfrontal & temporal lobes)
7g gyrus ambiens T5
7s collateral sulcus t4
8g lunate gyrus = uncus T5
8s sulcus semilunaris t5
9g medial occipitotemporal gyrus
= parahippocampal
gyrus O5/T5
10g lingual gyrus 0510l hippocampal lobule T5
10s hippocampal sulcus t5
11g occipitotemporal gyrus
inferiotemporal gyrus T3
12g lateral occipitotemporal
gyrus fusiform gyrus
occipitotemporal gyrus T4
13g inferior-occipital gyrus O3
14g cingulate gyrus F5/P5
15f Sylvian fissure =
lateral sulcus
16g precentral gyrus 1o
motor area F3
16s central sulcus
17g postcentral sulcus 1o
sensory area P1
18g paramarginal gyrus P3
19g angular gyrus
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1g=F4
3g4g
6f5g
7g
8s
8g
12g
10s9g
10g13g14g
11g
7s
10L11s
3s
2s
1s=f42g
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Cerebral gyri and sulci cont
20g superior temporal gyrus T1
21g middle temporal gyrus T2
22s Occipitotemporal sulcus b/n Occipital &
Temporal lobes
23s Calacarine sulcus (meets 22s)
24g Hippocampal gyrus T5
25 Cuneus O126 Precuneus O2
27g Cingulate gyrus
27s Cingulate sulcus
28 Corpus callosum
28s Corpus callosum sulcus
superior-anterior projection of the CC = frontal pole
posterior part of the CC = occipital pole
inferior anterior projection of CC temporal pole
cingular gyrus = small GM just above corpus callosumdentate gyrus = posterior layered part of the hippocampal gyrus
undergoes neogenesis in the adult for new memories ?
fornicate gyrus = cingulate + parahippocampal gyri (fornix)
note there are also 5 gyri in the Insula I1-5
i = pars operculus
ii = pars triangularus
iii = pars orbicularis all parts of F3 = inferior frontal gyrus
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