The a to Z of the Brain - BOOK

8/7/2019 The a to Z of the Brain - BOOK

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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

The A to Z of the Brain

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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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29 A. L. Neill

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

C


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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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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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3 2 4 5

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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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2

3 4

5

6

7

89

10

11

12

9

12 13 14 2p1

2L

4

3

5

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2a9

1011

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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


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

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3

2

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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

A. L. Neill38

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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39 A. L. Neill

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2

1

18

17

1615

1413

1211

109

8

7

6

5

2019

30

19

2

1

27

1816

25

14

272625

10

8

9

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23

6

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21


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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.

THE BRAIN

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Brain Development and Organization

foramen magnum

(exit from skull)


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41 A. L. Neill

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

THE BRAIN

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11 AM

12 PM13 Choroid plexus



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43 A. L. Neill

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

THE BRAIN

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10

7

3

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5

4

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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

THE BRAIN

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2

1

4

3

10

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9


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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


THE BRAIN

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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


THE BRAIN

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9v

16

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2v

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3

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5

6

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15


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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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5

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HEADACHE diagnoses = changes in

THE BRAIN

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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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55 A. L. Neill

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

NEUROLOGICAL ASSESSMENT

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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


57 A. L. Neill

SPONTANEOUS TO SPEECH TO PAIN via pressure

to the supraorbital N


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NEUROLOGICAL ASSESSMENT

A. L. Neill58

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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59 A. L. Neill

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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61 A. L. Neill

9v10 11 1 2 3p

4

5e

5m

3a

3

6

7R

8

12sp

3m

109v

11

15

5m

5e

7R5m

14

12sp

3

6

13

16

9

12s


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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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63 A. L. Neill

918

1920

21

22

2324-324-624-4

24-5

25s25i

7R

27

926

28

27e

7L

29

30

31

5e

9

9v

17

13

13

5m

5e

16

5e

4

3a

5m

13

6

3p

10

2

163332


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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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8

6

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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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7i

9

6

5

24

31i2

1s


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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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69 A. L. Neill

18

17M

20 2

122

1

a

1p

23

3n

1

2

4a

5

4m

9345

i

9-2

6

10

12

11

14

15

16

13

17e

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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See the website for more details on the Blood Vs and

CNs relationships.


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10 65i

9

9s 1-41-3 3

4

1-2

1-1

7

5i

6

5s4m

4e321-51-6

1-7,8

1-9,10

13

12

11

10e

101-11 1-12

14p15p16

7i

1-2

5s

17

8

1-L

1-2

1-31-4

1-61819204m9s

1-5

16

1-4

13

2122


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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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81 A. L. Neill

The a to Z of the Brain - BOOK

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