NEUROLOGIC INTERVENTIONS FOR PHYSICAL THERAPY SUZANNE "TINK"MARTIN, PT,MACT Professor Department of PhysicalTherapy University of Evansville Evansville,Indiana MARY KESSLER,PT,MHS AssociateProfessorandChair Departmentof PhysicalTherapy University of Evansville Evansville,Indiana .. C~1':,f\1'{I SAUNDERS ELSEVIER 11830 WestlineIndustrialDrive St.Louis,Missouri63146 NEUROLOGICINTERVENTIONSFOR PHYSICAL THERAPY,ED 2 Copyright ,g2007,2000by Saunders,an imprint of Elsevier Inc. ISBN-13: ISBN-lO: 978-0-7216-0427-5 0-7216-0427-7 Allrightsreserved.Nopartof thispublicationmaybereproducedortransmittedinanyformorbyany means,electronicormechanical,including photocopying,recording,oranyinformation storageand retrieval system, withoutpermissioninwriting fromthepublisher. PermissionsmaybesoughtdirectlyfromElsevier'sHealthSciencesRightsDepartmentinPhiladelphia,PA, USA:phone:(+1)2152393804,fax:(+1)2152393805,e-mail:healthpermissions@elsevier.com.Youmay alsocompleteyourrequeston-lineviatheElsevierhomepage(http://www.elsevier.com).byselecting 'Customer Support'andthen 'Obtaining Permissions'. Notice Neither thePublishernortheAuthorsassumeanyresponsibilityforanylossor injury and/or damageto personsor property arisingout of or relatedtoanyuseof thematerialcontained in thisbook.It isthe responsibility of thetreatingpractitioner,relyingon independent expertiseandknowledgeof thepatient, todeterminethebesttreatment and methodof applicationforthepatient. ThePublisher Previousedition copyrighted2000 ISBN-13:978-0-7216-0427-5 ISBN-I0:0-7216-0427-7 Publishing Director:LindaDuncan Senior Editor:KathvFalk Senior Editor:ChristieHart Developmental Editor:SueBredensteiner Publishing Servias Manager: JulieEddy Project Manager:AndreaCampbell DesignDirection:TeresaMcBryan IWorking together togrow Ilibrariesindeveloping countries PrintedintheUnitedStatesof America www.elsevieLcomI www.bookaid.orgI www.sabre.org Lastdigitisthe print number:98762 ELSEVIERSabre FoundatIon j ,Contributors ! ," TerryChambliss,PT,MHS Chapter 9,PNF Assistant Professor Departmentof PhysicalTherapy University of Evansville Evansville,Indiana Cathy JeremiasonFinch,PT Chapter 9,PNF Faculty Member Department of HealthScience PhysicalTherapist AssistantProgram KirkwoodCommunity College Cedar Rapids,Iowa PamRitzline,PT,PhD EvolveSite Director PostprofessionalDoctorateProgram GraduateSchoolof PhysicalTherapy University of Indianapolis Indianaoplis,Indiana Mary KaySolon,PT,PhD EvolveSite Chairman PhysicalTherapist Assistant Program University of St.Francis Fort Wayne,Indiana v Preface Wearegratifi.edbytheverypositiveresponsegiventothe firsteditionof NeurologicIntervention forP1J)JsicalTherapist Assistants.Inan effortto make a goodreferenceevenbetter, wehavetakenthe adviceof reviewersandour physical therapyandphysicaltherapistassistantstudentstocompletea secondedition.Thesequenceof chaptersnowreflectsa developmentaltrendwithmotordevelopment,handling, andpositioningandinterventionsforchildrencoming beforethecontentonadults.Chaptersonproprioceptive neuromuscularfacilitation(PNF)andother neurologicdisorderswill,wehope,bewelcomeadditionstothisedition. PNFremainsavaluableadjuncttothetreatmentof individualswithneuromuscularimpairments;therefore,we soughtcontributorswithexpertiseandexperienceto developthischapter.Thechapteronotherneurologicdisorders hasbeen addedafter theexpected chapters on stroke, traumaticbraininjury,andspinalcordinjury.Thechronic and,insomecases,progressivenatureof theseother disordersmakesthemparticularlychallenging.Allpatientcases havebeenreworkedintoGuideformatforeaseof learning andconsistencyindocumentation. Thechangeinthetitleof thebookcameaboutaswe discoveredthatthetextwasbeingusedasalabmanualfor neurorehabilitationcoursesinphysicaltherapyprograms. Weseethisasagooduseof thetextbookandthename changeembracesitsbroaderappeal.However,thename changedoesnotmeanthat wehavedroppedtheemphasis ontheroleof thephysicaltherapistassistantintreating patients with neurologic deficits.On the contrary, the useof thetextbookbyphysicaltherapystudentsshouldincrease theunderstanding of and appreciationforthepsychomotor andcriticalthinkingskillsneededbyallmembersof the teamtomaximizethefunctionof patientswithneurologic deficits.WearethrilledtobeabletoaddtheEvolvesite because wethink itwillbeanexcellentresourceforfaculty andstudents. Themarkof sophisticationof anysocietyishowwellit treatstheyoungandold-themostvulnerablesegmentsof thepopulation.Wehopeinsomesmallmeasurethatour continuing efforts willmakeiteasier tounravelthemystery of directingmovement,guidinggrowthanddevelopment, andrelearninglostfunctionalskillstoimprovethequality of lifeof thepeopleweserve. TinkMartin Mary Kessler ix Preface tothe First Edition Physicaltherapist assistantsareproviding more andmoreof the physical therapy caretoindividuals with neurologic dysfunction.Therewasnotextbookthatwethoughtspecificallycoveredneurologicinterventionsforthephysical therapistassistant,sowetook on thechallenge.Becausewe havetaughtphysicaltherapistassistantsaboutneurologic treatmentinterventionsforadultsandchildrenformany years,itseemedalogicalsteptoputtheanatomy,pathology,andtreatment together ina textbook. Thistextbook providesa link betweenthepathophysiologyof neurologicconditionsandpossibleinterventionsto improvemovement outcomes. What startedasa techniques bookhas,wehope,transcendedacookbookapproach,to providebackgroundinformationregardinginterventions that can be usedin the rehabilitation of adultsand children. Wearehopefulthatthistextwillassiststudentphysical therapist assistantsin their acquisition of knowledgeregardingthetreatmentof adultsandchildrenwithneurologic dysfunction. Writing isnot theeasiestthingtodo,asTink hadpreviously experienced in authoring anentry-leveltext.However, wethoughtasecondbookwouldbemanageable. Colleaguesencouragedus,studentscritiquedit,reviewers reviewedit,andourspousestacitlysupportedalltheextra hours given to the writing.Although the task seemeddaunting,wethought theproject couldrealisticallybecompleted inthreeyears.Fiveyearslater,wefeeljoy,relief,happiness, andarealsenseofaccomplishmentthattheprojectis finallycompleted. One alwaysembarks hoping forclear sailing with a quick passagetothedestination.Aswithmostthings,lifeintervenes.Wehaveperseveredandhopethat theend result will meet itsintendedpurpose-to teachandprovidea basisfor physicaltherapistassistantstolearnhowtoimplement interventionswithintheirknowledgebaseandabilities.In addition,itisourhopethatacademiciansinvolvedinthe educationof physicaltherapistassistantswillfindthistext tobea usefulreference. Themarkof sophisticationof anysocietyishow wellit treatsthe young andtheold,themostvulnerablesegments of thepopulation. Wehope in some smallmeasurethat our effortswillmake it easier to unravelthe mystery of directing movement,guidinggrowthanddevelopment,andrelearning lost functionalskillsto improve thequality of lifeof the peopleweserve. Tink Martin MaryKessler xi Acknowledgments I againwanttoacknowledgethededication andhard work of my colleague,friend,andcoauthor, Mary Kessler.Specialthanksgoto PamRitzlineandMary KaySolonfortheir exemplary contributiontotheEvolvesite.Alsothanksto TerryChamblissandCathy Finchfortheir work on thePNF chapter.Donna Cechwaskindenoughtoprovidefeedbackonthepediatric casesasthey were updatedtoGuideformat.Thank youtothestudentsattheUniversityof Evansville.Youarereally thereasonthisbook happenedinthefirstplaceandthereasonit hasevolvedintoitspresentform. Lastbutnot least,Iwant toacknowledgethe work of SueBredensteiner,our development editor. Shekept usgoing inthecorrectdirectionandhelpeddiffusethefrustrationthat inevitablyoccurs in projectsof thisnature.Yourfeedbackwassuper. Tink Imust thank my goodfriend,mentor,colleague,andcoauthor, Tink Martin.Without Tink,neither of theseeditionswouldhavebeen completed.Shehascontinuedtotakecareof many of the details,alwayskeepingusfocusedon the endresult.Tink'songoing encouragementandsupport havebeen most appreciated. Aspecialthank youtoallof thestudentsattheUniversityof Evansville.Theyarethereasonthat weoriginallystartedthisproject.Additionalthanksmust beextendedtoDr.PamRitzline,Mary KaySolon, Janet Szczepanski,and TerryChambliss forallof thesuggestionstheyofferedto improvetheoverallexcellenceof themanuscript.Other recognitionisnecessary forSuzy Sims,a dear friendwho isthepatient model in the newchaptersandour twograduates,Beth Jankauski andAmandaFisher,whoseassignmentsappear inthistext. Mary xii Contents SECTION FOUNDATIONS C HAP T E R1 The Role of the Physical Therapist and PTAssistant in Neurologic Rehabilitation,3 Introduction,3 TheRoleof thePhysicalTherapist inPatientManagement,4 TheRoleof thePhysicalTherapist AssistantinTreating PatientswithNeurologicDeficits,5 ThePhysicalTherapist Assistantasa Member of theHealthCare Team,6 Chapter Summary,6 ReviewQuestions,7 CHAPTER2 Neuroanatomy,8 Introduction,8 Major Componentsof theNervousSystem,8 Reactionto Injury,25 Chapter Summary,27 Review Questions,27 CHAPTER3 Motor Control and Motor Learning,28 Introduction,28 Motor Control,28 Relationshipof Motor Controlwith Motor Development,39 Motor Learning,39 RelationshipofMotor Learningwith Motor Development,42 Chapter Summary,45 ReviewQuestions,45 C HAP TE R4 Motor Development,47 Introduction,47 Developmental TimePeriods,48 Influenceof CognitionandMotivation,49 DevelopmentalConcepts,51 DevelopmentalProcesses,54 Gross- andFine-Motor Milestones,54 TypicalMotor Development,59 Posture,Balance,andGait Changes withAging,77 Chapter Summary 79 ReviewQuestions,80 SECTION CHILDREN CHAPTER5 Positioning and Handling to Foster Motor Function,85 Introduction,85 ChildrenwithNeurologicDeficits,85 GeneralPhysicalTherapy Goals,85 FunctionRelatedtoPosture,86 PhysicalTherapyIntervention,87 PositioningandHandlingInterventions,88 PreparationforMovement,99 Interventions toFoster HeadandTrunkControl,101 AdaptiveEquipment forPositioningandMobility,113 FunctionalMovement inthe Contextof the Child'sWorld,119 Chapter Summary,120 ReviewQuestions,121 CaseStudies:ReviewingPositioningandHandling Care:Josh,Angie,andKelly,122 xiii xivCONTENTS CHAPTER6 Cerebral Palsy,124 Introduction,124 Incidence,124 Etiology,124 Classification,126 Diagnosis,129 Pathophysiology,129 AssociatedDeficits,129 PhysicalTherapyExamination,132 PhysicalTherapy Intervention,135 Chapter Summary,150 ReviewQuestions,150 CaseStudies:RehabilitationUnitInitialExamination andEvaluation:Jennifer,151 Questions to Think About,152 C HAPT E R7 Myelomeningocele,155 Introduction,155 Incidence,155 Etiology,155 PrenatalDiagnosis,157 ClinicalFeatures,157 PhysicalTherapyIntervention,162 Chapter Summary,180 ReviewQuestions,180 RehabilitationUnitInitialExamination andEvaluation:Paul,181 Questions to Think About,182 CHAPTER8 Genetic Disorders,184 Introduction,184 Genetic Transmission,184 Categories,184 DownSyndrome,185 Cri-du-ChatSyndrome,188 Prader-WilliSyndrome,188 ArthrogryposisMultiplexCongenita,190 OsteogenesisImperfecta,193 CysticFibrosis,197 SpinalMuscular Atrophy,202 Phenylketonuria,205 DuchenneMuscular Dystrophy,205 BeckerMuscular Dystrophy,210 FragileX Syndrome,210 RettSyndrome,212 GeneticDisordersandMentalRetardation,213 Chapter Summary,221 ReviewQuestions,221 CaseStudies:RehabilitationUnitInitialExamination, andEvaluation:Ann,222 CaseStudies:RehabilitationUnitInitialExamination andEvaluation:John,224 Questions to Think About,226 SECTION ADULTS CHAPTER9 Proprioceptive Neuromuscular Facilitation,231 Introduction,231 History of Pr'\IF,231 BasicPrinciples of PNF,231 BiomechanicalConsiderations,234 Patterns,234 PI\JFTechniques,253 DevelopmentalSequence,261 Pr'\IFandMotor Learning,280 Chapter Summary,280 ReviewQuestions,281 CHAPTER10 Cerebrovascular Accidents,282 Introduction,282 Etiology,282 MedicalIntervention,283 Recovery fromStroke,283 Preventionof Cerebrovascular Accidents,284 StrokeSyndromes,284 ClinicalFindings:PatientImpairments,286 TreatmentPlanning,291 ComplicationsSeenFollowingStroke,291 AcuteCareSetting,292 DirectingInterventions toa Physical TherapistAssistant,292 xv EarlyPhysicalTherapyIntervention,293 Midrecovery toLateRecovery,336 Chapter Summary,344 ReviewQuestions,344 CaseStudies:RehabilitationUnitInitialExaminationand Evaluation:Ben,345 Questions to Think About,348 CHAPTER11 Traumatic Brain Injuries,350 Introduction,350 Classificationsof BrainInjuries,350 Secondary Problems,352 PatientExaminationandEvaluation,353 PatientProblemAreas,354 PhysicalTherapyIntervention:Acute Care,355 PhysicalTherapyInterventionsDuringInpatient Rehabilitation,361 IntegratingPhysicalandCognitiveComponents of a Taskinto TreatmentInterventions,367 DischargePlanning,372 Chapter Summary,373 ReviewQuestions,373 Case Studies:RehabilitationUnitInitialExamination andEvaluation:Rick,374 Questions to Think About,376 CHAPTER12 Spinal Cord Injuries,378 Introduction,378 Etiology,378 Naming theLevelofInjury,378 MechanismsofInjury,380 MedicalIntervention,380 Contents PathologicChanges That OccurFollowingInjury,382 TypesofLesions,382 ClinicalManifestationsof SpinalCordInjuries,385 Resolutionof SpinalShock,385 Complications,385 FunctionalOutcomes,389 PhysicalTherapyIntervention:Acute Care,392 PhysicalTherapyInterventionsDuring InpatientRehabilitation,397 Body WeightSupport TreadmillAmbulation,433 DischargePlanning,435 Chapter Summary,437 ReviewQuestions,437 Case Studies:RehabilitationUnitInitialExamination andEvaluation:Bill,439 Questions to Think About,441 CHAPTER13 Other Neurologic Disorders,443 Introduction,443 ParkinsonDisease,443 Multiple Sclerosis,451 Guillain-BarreSyndrome,460 PostpolioSyndrome,464 Chapter Summary,468 ReviewQuestions,469 CaseStudies:RehabilitationUnitInitialExamination, andEvaluation:Joshua,469 Questions to Think About,471 Answers to the Review Questions,475 Index,481

CHAPTER 1TheRoles ofthe Physical Therapist andPTAssistant in Neurologic Rehabilitation oBJ ECTIVESAfter readingthischapter,thestudent will beableto 1.UnderstandtheNagiDisablementModel. 2.Explaintheroleof thephysicaltherapistinpatientmanagement. 3.Describetheroleofthephysicaltherapistassistantinthetreatmentofadultsandcrlildren withneurologicdeficits. INTRODUCTION The practice of physical therapy in the United States continues tochangetomeettheincreaseddemandsplacedonservice provision by managedcareandfederalregulations.The professionhasseenanincreasednumberof physicaltherapist assistants(PTAs)providingphysicaltherapyinterventions foradultsandchildrenwithneurologicdeficits.PTAsare employedinoutpatient clinics,inpatientrehabilitationcenters,extendedcareandpediatricfacilities,schoolsystems, andhomehealthcareagencies.Traditionally,therehabilitationmanagementof adultsandchildrenwithneurologic deficitsconsistedof treatmentderivedfromtheknowledge of diseaseandinterventionsdirectedattheameliorationof patient signsand symptoms.The current viewof healthand diseasehasevolvedfroma traditional model basedsolely on pathology and clinical course toa health status model based on thedisablementprocess. Sociologist SaadNagidevelopeda modelof health status thatisusedtodescribetherelationshipbetweenhealthand function(Nagi,1991).Thefourcomponentsof theNagi DisablementModel(disease,impairments,functionallimitations,anddisability)evolveastheindividualloseshealth. Diseaseisdefinedasapathologicstatemanifestedbythe presenceof signsandsymptomsthat disruptanindividual's homeostasisorinternalbalance.Impairmentsarealterations inanatomic,physiologic,orpsychologicstructuresor functions.Functional limitationsoccurasaresultof impairments and become evident when an individual isunable toperform everydayactivitiesthatareconsideredpartof theperson's dailyroutine.Examplesof physicalimpairmentsincludea lossof strengthintheanteriortibialismuscleoralossof 15degreesof activeshoulder flexion.Thesephysicalimpairmentsmayor maynotlimittheindividual'sabilitytoperformfunctionaltasks.Inabilitytodorsiflextheanldemay prohibitthepatientfromachievingtoeclearanceandheelstrikeduringambulation,whereasaIS-degreelimitationin shoulder rangemay havelittleimpact on the person's ability toperform self-careor dressing tasks. Accordingtothedisablementmodel,adisabilityresults when functional limitations become so great that the person isunabletomeetage-specificexpectations withinthesocial orphysicalenvironment(VerbruggeandJette,1994). Societycanerectphysicalandsocialbarriersthatinterfere with a person's abilitytoperform expectedroles.Thesocietalattitudesencounteredbyapersonwithadisabilitycan resultinthecommunity'sperceptionthattheindividualis handicapped.Figure1-1depictstheNagiclassificationsystemof health status. TheGuide toPhysical Therapist Practicehasincorporatedthe NagiDisablementModelintoitsconceptualframeworkof physicaltherapy practice.Theuseof thismodel directsphysicaltherapists(PIs)tofocusontherelationshipbetween impairment and functionallimitation and thepatient's ability toperform everyday activities.Increasedindependenceinthe homeandcommunityandimprovementintheindividual's qualityof lifearetheexpectedoutcomesof ourtherapeutic interventions.Itisimportanttonote,however,thatprogressionfromastateof healthtooneof diseaseanddisabilityis not aninevitablepart of thedisablement model.PIs may preventimpairments,functionallimitations,ordisabilitiesby identifYingdisablementriskfactorsthatmayimpedepatient functioningand"bybufferingthedisablementprocess" (APIA, 2001).Moreover,"physical therapists arealso involved in promoting health, wellness,andfitnessinitiatives including 3 4SECTION1FOUNDATIONS Disease~__D_i_sa_b_il_ity_...... Handicap ~[ lFunctionallimitation PathologyAlterationDifficulty performingSignificant ofstructureroutine tasksfunctionallimitation; andfunctioncannot perform expected tasks FIGURE1-1.Nagiclassificationsystem of healthstatus. Societal disadvantage ofdisability educationandserviceprovision,thatstimulatethepublicto engageinhealthy behaviors"(APIA,2001). TheGuidetoP ~ y s i c a l TherapistPractice(APIA,2001) defines functionas"those activitiesidentifiedby an individualasessential tosupport physical,socialand psychological well-being andtocreatea personalsenseof meaningfulliving." Functionisrelatedto age-specificrolesin a givensocial contextandphysicalenvironment.Functionisdefineddifferentlyforachildof 6months,anadolescentof 15years, anda65-year-oldadult.Factorsthatdefineanindividual's functional performance include personal characteristics suchas physicalability,emotionalstatus,andcognitiveability;the environmentinwhichthepersonfunctions,suchasthe home,school,orcommunity;andthesocialexpectations placedon theperson'sperformanceby family,the community,or societyin general(Fig.1-2). Variousfunctionalskillsareneededindomestic,vocational,andcommunity environments.Performanceof these skillsenhances the individual's physical and psychologic wellbeing.Individuals define themselvesby what they areableto accomplish and how they areableto participate inthe world. FIGURE1-2.Factorsdefininganindividual'sfunctionalperformance.(FromCechD,MartinS.Functional Movement Development AcrosstheLifeSpan,2ndedition.Philadelphia,WBSaunders, 2002,Figure 1-3, p.8.) Performance of functional tasksnot only dependson anindividual's physical abilities but isalsoaffectedby emotional status,cognitiveabilities(intellect,motivation,concentration, problem-solving skills),andanindividual'sabilitytointeract withpeopleandmeetsocialandculturalexpectations(Cech andMartin,2002).Furthermore,individualfactorssuchas congenitaldisordersandgeneticpredispositiontodisease, demographics(age,sex,levelofeducationandincome), comorbidities,lifestylechoices,healthhabits,andenvironmental factors(including accessto medical and rehabilitation careandthephysicalandsocialenvironments)mayalso affectthedisablementprocess(APIA, 2001). THEROLEOF THEPHYSICALTHERAPIST INPATIENTMANAGEMENT PIs"provideservicestopatients/clientswhohaveimpairments,functionallimitations,disabilities,orchangesin physicalfunctionandhealthstatusresultingfrominjury, disease,or other causes" (APIA, 2001).Ultimately,the PI is responsible for examining the patient and developing a plan of carethatmeetsthegoalsandfunctionalexpectationsof thepatient (O'Sullivan,2001). ThestepsthePI utilizesinpatient managementareoutlinedintheGuidetoPhysicalTherapistPracticeandinclude examination,evaluation,diagnosis,prognosis,intervention,and outcomes.Figure1-3identifiestheseelements.Intheexamination,the PI collectsdatathrougha reviewof the patient's historyandbodysystemsandcompletesappropriatetests and measures. The PI then evaluates the data and makesclinicaljudgmentsrelativetotheseverityof thepatient'sproblems.Establishmentof a physical therapydiagnosisbasedon thepatient'slevelof impairment andfunctionallimitations isthenextstepinthisprocess.Oncethediagnosisiscompleted,thePI developsa prognosisandthepatient's planof careincludingshort- andlong-termgoals.Information regardinganticipateddischargeplansshouldalsobe includedintheplanof care.Interventionistheelementof patientmanagementinwhichthePI orthePIAinteracts withthepatientthroughtheadministrationof"various physicaltherapyproceduresandtechniquestoproduce changesinthe[patient's]conditionthatisconsistentwith thediagnosisandprognosis"(APIA,2001).Reexamination of thepatient isalsoconsideredapartof intervention.The finalcomponentrelatedtopatientmanagementisoutcomes assessment.The PI must determinethe impact selected interventionshavehadonthepatient'sfunctionalstatusand quality of life(APIA,2001). TheRolesofthePhysicalTherapistandPTAssistantinNeurologicalRehabilitationCHAPTER15 DIAGNOSIS Interpret evaluationexaminationdata Organize data into defined clusters, syndromes,or categories Determineprognosis andplanof care ? Planthemost appropriate intervention strategies ~EVALUATION PROGNOSIS(IncludesPlanof Care) judgments based ondata gatheredduring Utilize this dynamic process tomake clinical Determinelevelof optimalimprovement thepatient/client examinationexpected frominterventions Recognize andidentify problems thatrequireAssess amount of timerequiredtoreach consultation withor referraltoanotheroptimalimprovement level providerDocument planof care specifying the interventions tobeused,timing,and r frequency.. EXAMINATION Obtaina history Perform a systemsreview INTERVENTIONSelect andadminister tests andmeasures to Apply purposefuland skilledinteractionwith gather data about the patient/client the patient/client and,if appropriate,with Utilize theinitialexaminationasa comprehensive other individuals involved inthepatient/ screening andspecific testingprocess to client's care leadtoa diagnostic classification Utilize various physical therapymethods and Identify problems thatrequireconsultationwith techniques toproduce changesintheorreferraltoanother provider patient/client's conditionconsistent with diagnosis andprognosis Assess thepatient/client fornew clinical OUTCOMESfindingsor lack of progress Reexaminepatienllclient status todetermine Resultsof patient/client management,whichinclude theimpact changesinstatusandtomodify orredirect of physical therapy interventions inthe followingdomains intervention Pathology/pathophysiology (disease,disorder or condition)Identify thepossibleneedfor consultation Impairments, functionallimitations,anddisabilitieswithor referraltoanother provider Risk reduction/prevention Health,wellness,andfitness Societalresources Patient/client satisfaction FIGURE 1-3.The elements of patient/client management leadingto optimaloutcomes.(From AmericanPhysicalTherapy Association(APTA).Guide to Physical Therapist Practice,2ndedition. Alexandria,VA,APTA,2001,Figure1,p.S35.) THEROLEOFTHEPHYSICALTHERAPIST ASSISTANTINTREATINGPATIENTSWITH NEUROLOGICDEFICITS LittleornodebateexistsonwhetherPTAshavearolein treatingadultswithneurologicdeficits,aslongastheindividual needs of the patient aretaken into consideration. The primary PTisstillultimately responsiblefor the patient and theactionsofthePTArelativetopatientmanagement (APTA,2003a).ThePTsupervisesthePTAwhenthePTA providesinterventionsselectedbythePT.TheAmerican PhysicalTherapy Association(APTA)hasidentifiedthefollowingresponsibilitiesasthosethatmustbeperformed exclusivelybythePT(APTA,2003a): 1.Interpretationof thereferralwhen available 2.Initial examination, evaluation, diagnosis, and prognosis 3.Development andmodificationof theplanof care 4.Determinationof whentheexpertiseanddecisionmakingcapabilitiesofthePTareneededinthe provisionof patientcareandwhenitmaybeappropriatetoutilizeaPTA 5.Reexaminationof the patient and revisionof the plan of careif indicated 6.Establishmentof thedischargeplananddocumentationof thedischargesummary 7.Oversightof alldocumentation APTApolicydocumentsalsostatethatinterventionsthat requireimmediateandcontinuousexaminationandevaluation are to be performed exclusively by the PT (APTA,20mb). Prior todirecting thePTAto performspecificcomponents oftheintervention,thePTmustcriticallyevaluatethe patient'scondition(stability,acuity,criticality,andcomplexity) andconsiderthepracticesetting,thetypeof interventionto beprovided,andthepatient'sprobableoutcome(APTA, 2003a).In addition, the knowledgebaseof the PTA and hisor her levelof experienceandtraining must beconsidered when determiningwhichtaskscanbedirectedtothePTA.Inthe current health careclimate,therearetimes when the decision asto whether a patient may betreated by a PTA isdetermined bythepatient's insurance coverage.Some insurance plans will notpayforservicesprovidedbyaPTA.Consequently, SECTION1FOUNDATIONS 6 decisions regarding the utilization ofPTAs may be determined byfinancialremuneration andnot theneedsof thepatient. AlthoughPTAswork withadultswhohavehadcerebrovascularaccidents,spinalcordinjuries,andtraumaticbrain injuries,somePTsstillviewpediatricsasaspecialtyareaof practice.ThisnarrowperspectiveisheldeventhoughPTAs workwithchildreninhospitals,schools,andthecommunity.Althoughsomeareasof pediatricphysicaltherapyare specialized,many areasarewellwithinthescopeof practice of thegeneralistPTandPTA(MillerandRatliffe,1998).To assistinresolvingthiscontroversy,thePediatricSectionof theAmericanPhysicalTherapyAssociation(APTA)developed a draft position statement outlining theuseofPTAsin variouspediatricsettings.Theoriginalpositionpaper stated that "physicaltherapist assistantscould beappropriately utilized in pediatric settings with the exception of the medically unstable,suchasneonatesintheleu"(Sectionon Pediatrics,APTA,1995).Thisdocument wasrevisedin1997 andisavailablefromtheSectiononPediatrics.Themost recentpositionpapernowstatesthat"the physicaltherapist assistantisqualifiedtoassistintheprovisionof pediatric physicaltherapy servicesunder the direction and supervision of a physicaltherapist.ItisrecommendedthatPTAsshould notprovideservicestochildrenwhoarephysiologically unstable(SectiononPediatrics,APTA,1997).Inaddition, thispositionpaperalsostatesthat"delegationof physical therapy procedures to a PTA should not occur when a child's conditionrequiresmultipleadjustmentsof sequencesand proceduresduetorapidlychangingphysiologicstatus and/or responsetotreatment"(Section on Pediatrics, APTA, 1997).Theguidelinesproposedinthisdocumentfollow thosesuggestedbyNancyWattsinher1971articleontask analysisanddivisionof responsibilityinphysicaltherapy (Watts,1971). This article waswritten to assist PTs with guidelinesfordelegating patient careactivitiestosupportpersonnel.Althoughthetermdelegationisnotusedtodaybecause of theimplicationsof turningoverpatientcaretoanother practitioner,theprinciplesof patientor clientmanagement asdefmedby Wattscanbeappliedtotheprovision of present-dayphysicaltherapyservices.PTsandPTAsunfamiliar withthisarticleareencouragedtoreviewitbecausethe guidelinesset fortharestill appropriate for today'sclinicians. THEPHYSICAL THERAPISTASSISTANTAS AMEMBEROFTHEHEALTHCARETEAM The PTAfunctionsasa member of therehabilitation teamin alltreatmentsettings.Membersof thisteamincludetheprimaryPT;thephysician;speech,occupational, andrecreation therapists; nursing personnel; the psychologist; and thesocial worker.However,thetwomostimportantmembersof this team arethe patient and family.In a rehabilitation setting, the PTAisexpectedto provide therapeutic interventionsto improve thepatient'sfunctionalindependence.Relearningmotor activitiessuchasbedmobility,transfers,ambulationskills, andwheelchairnegotiation,if appropriate,isemphasizedto enhancethepatient'sfunctionalmobility.Inaddition,the PTAparticipatesinpatientandfamilyeducationandis expectedtoprovideinputintothepatient'sdischargeplan. Patientandfamilyinstructionincludesprovidinginformation,education,andtheactualtrainingof patients,families, significantothers,or caregivers(APTA,2001).Asisthecase inallteamactivities,openandhonestcommunication amongallteammembersiscrucialtoachieveanoptimal functionaloutcome forthepatient. Therehabilitationteam working witha childwithaneurologic deficit usually consists of the child, hisor her parents, thevariousphysiciansinvolvedinthechild'smanagement, andotherhealthcareprofessionalssuchasanaudiologist, physicalandoccupationaltherapists,aspeechlanguage pathologist,andthechild'sclassroomteacher.ThePTAis expectedtobring certainskillstotheteamandtothechild, includingknowledgeof positioningandhandling,useof adaptiveequipment,managementofabnormalmuscle tone,andtheknowledgeof developmentalactivitiesthat fosteracquisitionof functionalmotor skillsandmovement transitions.Familyteachingandinstructionareexpected withina family-centeredapproachtothedelivery of various interventions. Because the PTA may be providing servicesto thechildinherhomeorschool,theassistantmaybethe fmttoobserveadditional problemsor betoldof aparent's concern.Theseobservationsorconcernsshouldbecommunicatedtothesupervising PTinatimely manner. PTsandPTAsarevaluablemembersof a patient'shealth careteam.Tooptimizetherelationshipbetweenthetwo andtomaximizepatientoutcomes,eachpractitioner must understandtheeducationalpreparationandexperiential background of the other. The preferred relationship between PTsandPTAsisone characterizedby "trust,mutual respect, and anappreciationforindividualandcultural differences" (APTA,2000).Thisrelationshipinvolvesdirection,includingdeterminationof thetasksthatcanbedirectedtothe PTA,supervisionbecausethePTisresponsibleforsupervisingtheassistanttowhomtasksorinterventionshavebeen directedand accepted,communication, and the demonstration of ethical and legalbehaviors.Positive benefitsthat can bederivedfromthispreferredrelationshipincludemore clearly defmedidentitiesforboth PTsandPTAsand amore unified approach to the delivery of high-quality, cost-effective physicaltherapyservices(APTA,2000). CHAPTERSUMMARY Changesinphysicaltherapypracticehaveledtoanincrease inthenumberofPTAsandgreatervarietyinthetypesof patients treatedby these clinicians.PTAs are actively involved in the treatment of adults and children with neurologic deficits. Afterathoroughexaminationandevaluationofthepatient's status,theprimaryPTmay determine that thepatient'sinterventionoraportionoftheinterventionmaybesafelyperformed by anassistant. The PTA functions as a member of the patient's rehabilitation team and works with the patient to minimize the effects of physical impairments and functionallimitations.Improvedfunctioninthehome,school,orcommunity remains theprimary goalof physicaltherapy interventions._ 7TheRolesofthePhysicalTherapistandPTAssistantinNeurologicalRehabilitationCHAPTER1 REVIEWQUESTIONS 1.Define the termimpairment according to theNagi Disablement Model. 2.List the factorsthataffect anindividual's performance of functionalactivities. 3.Identify the factors that the PTmust consider prior to utilizingaPTA. 4.Discuss therolesof thePTAwhenworkingwithadults or childrenwithneurologic deficits. REFERENCES American Physical Therapy Association(APTA).Guideto physical therapistpractice.PhysTher77: 1177-1187,1625-1636,1997. AmericanPhysicalTherapyAssociation(APTA).GuidetoPhysical TherapistPractice,2ndedition,Alexandria,VA,APTA,2001, ppS13-S42. AmericanPhysicalTherapyAssociation(APTA).Directionand supervisionof thephysicaltherapistassistant,HOD 06-00-16-27. Houseof Delegates:Standards,Policies,PositionsandGuidelines. Alexandria, VA,APTA,2003a. AmericanPhysicalTherapyAssociation(APTA).Procedural InterventionsExclusivelyPerformedbyPhysicalTherapists, HOD06-00-30-36.Houseof Delegates:Standards,Policies, Positionsand Guidelines.Alexandria,VA,APTA,2003b. AmericanPhysicalTherapyAssociationEducationDivision.A NormativeModelof PhysicalTherapistProfessionalEducation, Version2000.Alexandria,VA,APTA,2000,pp122-127. CechD,MartinS.Functional MovementDevelopment AcrosstheLife Span,2nd edition.Philadelphia, WBSaunders, 2002,pp3-18. Miller ME, Ratliffe KT.The emerging roleof thephysical therapist assistantinpediatrics.InRatliffeKT(ed).ClinicalPediatric Physical Therapy.StLouis,Mosby,1998,pp15-22. NagiS2.Disabilityconceptsrevisited:Implicationsforprevention.InPope AM, Tarlox AR (eds).Disability in America:Toward aNationalAgenda forPrevention.Washington,DC,National AcademyPress,1991,pp 309-327. O'SullivanSB.Clinicaldecisionmakingplanningeffectivetreatments.InO'SullivanSB,SchmitzTJ(eds).Pkysical Rehabilitation Assessment and Treatment,4th ed.Philadelphia,PA, Davis,2001,pp1-7. SectionofPediatrics,AmericanPhysicalTherapyAssociation. Draftpositionstatementonutilizationof physicaltherapist assistantsintheprovision of pediatric physical therapy.Section on Pediatrics Newsletter5: 14-1 7,1995. SectiononPediatrics,AmericanPhysicalTherapyAssociation. Utilizationof PhysicalTherapistAssistantsintheProvisionof Pediatric Pkysical Therapy.Alexandria,VA,APTA,1997. VerbruggeL,JetteA.Thedisablementprocess.SocSciMed 38:1-14,1994. WattsNT.Taskanalysisanddivisionof responsibilityinphysical therapy.PhysTher51 :23-35,1971. CHAPTER 2Neuroanatomy OBJECTIVESAfter readingthischapter,thestudentwill beableto 1.Differentiatebetweenthecentralandperipheralnervoussystems. 2.Identify significant structureswithinthenervoussystem. 3.Understandprimary functionsofstructureswithintilenervoussystem. 4.Describethevascularsupply tothebrain. 5.Discusscomponentsofthecervical,bracrlial,andlumbosacralplexuses. INTRODUCTION Thepurposeof thischapter istoprovidethestudent witha reviewof neuroanatomy.Basicstructureswithinthenervous system aredescribed and their functionsdiscussed.This information isimportant to physicaltherapistsand physical therapistassistantswhotreatpatientswithneurologicdysfunctionbecause it assistsclinicians with identifYing clinical signsand symptoms.In addition, it allowsthephysicaltherapistassistanttodevelopanappreciationof thepatient's prognosisandpotentialfunctionaloutcome.Itis,however, outsidethescopeof thistexttoprovideacomprehensive discussionof neuroanatomy.Thereaderisencouragedto reviewtheworksof Cohen(1999),Curtis(1990),Farber (1982),fitzGerald(1996),GilmanandNewman(2003), Littell(1990),Lundy-Ekman(2002),andothersforamore in-depthreviewof theseconcepts. MAJORCOMPONENTSOFTHENERVOUS SYSTEM Thenervoussystemisdividedintotwoparts,thecentral nervous system(CNS) andthe peripheral nervous system(PNS). TheCNSiscomposedof thebrain,thecerebellum,the brain stem,andthe spinal cord, whereasthePNScomprises allthecomponentsoutsidethecraniumandspinalcord. Physiologically, the PNS isdivided into the somatic nervous systemand the autonomic nervoussystem(ANS).Figure2-1 illustratesthemajor componentsof theCNS. Thenervoussystemisahighlyorganizedcommunication systemthat servesthebody.Nervecellswithinthenervoussystemreceive,transmit,analyze,and communicateinformation tootherareasthroughoutthebody.Forexample,sensations such astouch, proprioception, pain, and temperature aretransmittedfromtheperipheryaselectrochemicalimpulsestothe CNSthroughsensorytracts.Onceinformationisprocessed withinthebrain,it isrelayedasnew electrochemicalimpulses 8 to peripheral structures through motor tracts. This transmission process isresponsible foran individual's ability to interact with the environment. Individuals areable to perceive sensory experiences, to initiate movement, and to perform cognitive tasksas a resultof a functioningnervoussystem. TypesofNerveCells Thebrain,brainstem,andspinalcordarecomposedof two basictypesof nervecellscalledneuronsandneuroglia.Three differentsubtypesof neuronshavebeenidentifiedbasedon their function:(1)afferentneurons,(2)interneurons,and(3) efferentneurons.Afferentorsensoryneuronsareresponsible forreceivingsensoryinputfromtheperipheryof thebody andtransportingitintotheCNS.lnterneuronsconnectneuronstoother neurons.Their primaryfunctionistoorganize informationreceivedtrommanydifferentsourcesforlater interpretation. Efferent or motor neurons transmit information totheextremitiestosignalmusclestoproduce movement. Neurogliaarenon-neuronalsupportingcellsthatprovide critical services for neurons. Three different types of neuroglia (astrocytes,oligodendrocytes, and microglia) havebeen identified.Astrocytesareresponsibleformaintainingthecapillary endotheliumandassuchprovidea vascularlink toneurons. Additionally,astrocytescontributetothemetabolismof the CNSand regulateextracellular concentrations of neurotransmitters(GilmanandNewman,2003).Oligodendrocyteswrap myelinsheathsaroundaxonsinthewhitematterandproducesatellitecellsinthegraymatterthatparticipateinion exchangebetweenneurons.Microgliacellsareknownasthe phagocytesof theCNS.Theyengulf anddigestpathogens andassistwithnervoussystemrepair afterinjury. NeuronStructures Asdepictedin Figure2-2,aneuronconsistsof acellbody, dendrites,andanaxon.Thedendriteisresponsiblefor 9 CerebralCerebrum -- hemispheres Diencephalon Brainstem

andcerebellum - Pons Spinalregion Peripheralregion;\ FIGURE 2-1.Regions of the nervous system. Regions are listed onthe left,andsubdivisions arelistedontheright.(FromLundyEkmanL.Neuroscience:FundamentalsforRehabilitation,2nd edition.Philadelphia,WBSaunders, 2002.) receivinginformationandtransferringittothecellbody, whereit isprocessed.Dendritesbring impulses into thecell body fromother neurons.Thenumber andarrangementof dendrites present in a neuron vary.The cell body or soma is composedof anucleusandanumberof differentcellular organelles.Thecellbodyisresponsibleforsynthesizing proteins andsupporting functionalactivitiesof theneuron, suchastransmitting electrochemical impulsesandrepairing cells.CellbodiesthataregroupedtogetherintheCNS appeargrayandthusarecalledgraymatter.Groupsof cell bodieswithsimilarfunctionsareassembledtogetherto form nuclei. The axon isthe message-sending component of thenervecell.It extendsfromthecellbody andisresponsiblefortransmittingimpulsesfromthecellbodytotarget cells that can include muscle cells,glands,or other neurons. Synapses The space between the axon of one neuron and the dendrite of thenextneuroniscalledthesynapse.Synapsesarethe NeuroanatomyCHAPTER2 /I.'Myelinsheath FIGURE2-2.Diagramofaneuron. connectionsbetweenneuronsthatallowdifferentpartsof thenervoussystemtocommunicatewithandinfluence eachother.Anaxontransportselectricalimpulsesor chemicalscalledneurotransmitterstoandacrosssynapses.The relayingof informationfromoneneurontothenexttakes placeatthesynapse. Neurotransmitters Neurotransmittersarechemicalsthattransmitinformation acrossthesynapse.Anin-depthdiscussionof neurotransmittersisbeyondthescopeof thistext.Wewill,however, discusssomecommonneurotransmittersbecauseof their relationshiptoCNSdisease.Furthermore,manyof the pharmacologicinterventionsavailabletopatientswith CNSpathologyactbyfacilitatingorinhibitingneurotransmitteractivity.Commonneurotransmittersinclude acetylcholine,glutamate,y-aminobutyricacid(GABA), dopamine,andnorepinephrine."Acetylcholineistheneurotransmitter usedby allneurons that synapse withmuscle 10SECTION1FOUNDATIONS fibers(lowermotorneurons)"(Lundy-Ekman,2002). Acetylcholinealsoplaysaroleinregulating heartrateand otherautonomicfunctions.Glutamateisanexcitatory neurotransmitterandfacilitatesneuronalchangeduring development.Glutamateisalsothoughttocontributeto neurondestructionafteraninjurytotheCNS.GABAis aninhibitoryneurotransmitterandexertsitsinfluence over interneurons within thespinalcord.Dopamine influencesmotoractivity,motivation,andcognition. NorepinephrineisusedbytheANSandproducesthe "fight-or-flightresponse"tostress(Lundy-Ekman,2002). Axons Once information isprocessed, it isconducted to other neurons,musclecells,orglandsbytheaxon.Axonscanbe myelinatedorunmyelinated.Myelinisalipid/proteinthat encasesandinsulatestheaxon.Thepresenceof amyelin sheathincreasesthespeedofimpulseconduction,thus allowing for increased responsivenessof the nervous system. Themyelinsheathsurroundingtheneuronisnotcontinuous;itcontainsinterruptionsorspaceswithinthemyelin calledthenodesof Ranvier.Saltatoryconductionisthe process whereby electricalimpulsesareconductedalong an axon by jumping fromonenodetothenext(Fig.2-3).This processincreasesthevelocityof nervoussystemimpulse conduction.Unmyelinatedaxonssendmessagesmore slowlythan myelinatedones. WhiteMatter Areasof thenervoussystemwithahighconcentrationof myelinappearwhitebecauseof thefatpresentwithinthe myelin.Consequently,whitematteriscomposedofaxons thatcarryinformation awayfromcellbodies.Whitematter isfoundin thebrain andspinalcord.Myelinatedaxonsare bundledtogether withintheCNStoformfibertracts. GrayMatter Graymatterreferstoareasthatcontainlargenumbersof nervecellbodies and dendrites.Collectively,thesecell bod-MyelinsheathAxoplasmNodeofir-----J;i-ti::i:: '.~ ' . \~ ' . ~............................ .. .. .................... 1 2 3 FIGURE2-3.Saltatoryconductionalongamyelinatedaxon. (RedrawnfromGuytonAC,HallJE.TextbookofMedical Physiology,9thedition.Philadelphia,WBSaunders,1996.) iesgivethe region itsgrayishcoloration.Gray matter covers theentiresurfaceof thecerebrumandiscalledthecerebral cortex. The cortex isestimated to contain 14billion neurons (GilmanandNewman,2003).Graymatterisalsopresent deepwithinthespinalcordandisdiscussedinmoredetail later inthischapter. FibersandPathways MajorsensoryorajJerenttractscarryinformationtothe brain,andmajormotororefferenttractsrelaytransmissionsfromthebraintosmoothandskeletalmuscles. SensoryinformationenterstheCNSthroughthespinal cordorbythecranialnervesasthesensesof smell,sight, hearing,touch, taste,heat,cold, pressure, pain, and movement.Informationtravelsinfibertractscomposedof axonsthatascendinaparticularpathfromthesensory receptortothecortexforinterpretation.Motorsignals descendfromthecortextothespinalcordthroughefferent fibertractsformuscleactivation.Fibertractsaredesignatedbytheirpointof originandbytheareainwhich theyterminate.Thus,thecorticospinaltract,theprimary motor tract,originatesinthecortex andterminatesinthe spinalcord.Thelateralspinothalamictract,asensory tract,beginsinthelateralwhitematter of thespinalcord andterminatesinthethalamus.Amorethoroughdiscussionof motor andsensorytractsispresentedlaterinthis chapter. Brain Thebrainconsistsof thecerebrum,whichisdividedinto twocerebralhemispheres(therightandtheleft),thecerebellum,andthebrainstem.Thesurfaceof thecerebrumor cerebralcortex iscomposed of depressions(sulci)andridges (gyri).Theseconvolutionsincreasethesurfaceareaof the cerebrumwithoutrequiringanincreaseinthesizeof the brain.Theoutersurfaceof thecerebrumiscomposedof graymatterandisestimatedtobe1.3to4.5mmthick, whereastheinner surfaceiscomposed of whitematter fiber tracts(GilmanandNewman,2003).Therefore,information isconveyedbythewhitematter andisprocessedandintegratedwithinthegraymatter. Supportiveand Protective Structures Thebrainisprotectedbyanumber of differentstructures andsubstancestominimizethepossibilityof injury.First, thebrain issurroundedby a bony structurecalledtheskull orcranium.Thebrainisalsocoveredbythreelayersof membranescalledmeninges,whichprovideadditionalprotection.Theoutermost layer istheduramater.Theduraisa thick,fibrousconnectivetissuemembranethatadheresto thecranium.Theareabetween thedura mater andtheskull isknown asthe epiduralspace.The next or middle layer isthe arachnoid.Thespacebetweentheduraandthearachnoidis calledthesubdural space.Thethird protective layer isthe pia mater.Thisistheinnermostlayerandadherestothebrain 11 itselfThepiamateralsocontainsthecerebralcirculation. Thecranialmeningesarecontinuouswiththemembranes thatcoverandprotectthespinalcord.Cerebrospinalfluid bathesthebrainandcirculateswithinthesubarachnoid space.Figure 2-4showstherelationship of the skull with the cerebralmeninges. Lobesof theCerebrum Thecerebrumisdividedintofourlobes-frontal,parietal, temporal,andoccipital-eachhavinguniquefunctions,as showninFigure2-5,A.Thehemispheresofthebrain, althoughapparentmirror imagesof oneanother,havespecializedfunctionsaswell.Thissidednessof brainfunction iscalledhemisphericspecializationor lateralization. FrontalLobe.Thefrontallobeisfrequentlyreferredto astheprimary motor cortex.The frontallobeisresponsible forvoluntarycontrolof complexmotoractivities.Inadditiontoitsmotorresponsibilities,thefrontallobealso exhibitsa strong influenceover cognitivefunctions,includingjudgment,attention,awareness,abstractthinking, mood, andaggression.The principalmotor region responsibleforspeech(Broca'sarea)islocatedwithinthefrontal lobe.Inthelefthemisphere,Broca'sareaplansmovements ofthemouthtoproducespeech.Intheoppositehemisphere,thissameareaisresponsiblefornonverbal communication,includinggesturesandadjustmentsofthe individual'stoneof voice. Arachnoid Subarachnoid space Pia mater FIGURE 2-4.A coronal section through the skull,meninges, and cerebralhemispheres.Thesectionshowsthemidlinestructures near thetopof theskull.Thethreelayersofmeningesareindicated.(FromLundy-EkmanL.Neuroscience:Fundamentalsfor Rehabilitation,2ndedition.Philadelphia,WBSaunders,2002.) NeuroanatomyCHAPTER2 ParietalLobe.Theparietallobeistheprimarysensory cortex.Incomingsensoryinformationisprocessedand meaning isprovidedtostimuli withinthislobe.Perception istheprocessof attaching meaning tosensory information. Muchofourperceptuallearningrequiresafunctioning parietallobe.Specificbodyregionsareassignedlocations withintheparietallobeforthisinterpretation.Thismapping isknownasthesensory homunculus (Fig.2-5,B).The parietallobealsoplaysaroleinshort-termmemoryfunctions. TemporalLobe.Thetemporallobeistheprimaryauditorycortex.Wernicke'sareaof thetemporallobeallowsan individual tohear and comprehend spoken language. Visual perception,musicaldiscrimination,andlong-termmemory capabilitiesareallfunctionsof thetemporallobe. OccipitalLobe.Theoccipitallobeistheprimary visual cortex providing for the organization, integration, and interpretationof visualinformation.Theeyestakeinvisual informationandthensendittotheoccipitalcortexfor interpretation. AssociationCortex Associationareasareregionswithintheparietal,temporal, andoccipitallobesthathorizontally linkdifferentpartsof thecortex.For example,thesensory associationcortex integratesandinterpretsinformationfromallthelobesreceivingsensoryinputandallowsindividualstoperceiveand attachmeaning to sensory experiences. Additional functions of theassociationareasincludepersonality,memory,intelligence (problem solving and comprehension of spatialrelationships),andthegenerationof emotions(Lundy-Ekman, 2002).Figure2-5,C,depictsassociationareaswithinthe cerebralhemispheres. Motor Areasof theCerebralCortex The primary motor cortex, located in thefrontallobe, isprimarilyresponsibleforcontralateralvoluntarycontrolof upperextremityandfacialmovements.Thus,a greaterproportionof thetotalsurfaceareaof thisregionisdevotedto neuronsthatcontrolthesebodyparts.Othermotorareas includethepremotorarea,whichcontrolsmusclesof the trunkandanticipatoryposturaladjustments,andthesupplementarymotorarea,whichcontrolsinitiationof movement,orientationoftheeyesandhead,andbilateral, sequentialmovements(Lundy-Ekman,2002). HemisphericSpecialization The cerebrum can be further divided into theright and left cerebral hemi5phere5.Grossanatomicdifferenceshavebeendemonstratedwithinthehemispheres.Thehemispherethatis responsibleforlanguageisconsideredthedominanthemisphere. Approximately 95percent of the population, including allright-handedindividuals,arelefthemispheredominant. Eveninindividualswhoareleft-handdominant,theleft hemisphere isthe primary speech center in about 50 percent of B Lateral fissure Temporallobe c ,---=-__12SECTION1FOUNDATIONS Cerebrum Parietallobe Occipital lobe Centralsulcus Temporallobe Frontallobe Sylvian fissure A Sensory association areas Visualassociation areas FIGURE 2-5.The brain. A,Left lateral view of the brain,showing theprincipaldivisions of the brainandthe four major lobes of the cerebrum.B,Sensoryhomunculus.C,Primary andassociationsensoryandmotorareasofthebrain.(A,FromGuytonAC.BasicNeuroscience: Anatomy and Physiology,2ndedition.Philadelphia,WBSaunders,1991; Band C,fromCech D,MartinS.FunctionalMovementDevelopmentAcrosstheLifeSpan,2ndedition. Philadelphia,WBSaunders,2002.) thesepeople(GeschwindandLevitsky,1968;GilmanandLeftHemisphereFunctions.Thelefthemispherehas Newman,2003;Guyton,1991;Lundy-Ekman,2002).Table2-1beendescribedastheverbaloranalyticsideof thebrain. listsprimary functionsof both theleft and right cerebralhemi Thelefthemisphereallowsfortheprocessingof informaspheres.tioninasequential,organized,logical,andlinearmanner. NeuroanatomyCHAPTER213 Ii1D:DIBehaviors Attributed to theLeft andRightBrainHemispheres Behaviorleft HemisphereRightHemisphere Cognitivestyle Perception/cognition Academicskills Motor Emotions Processinginformationina sequential,linear manner Observingandanalyzingdetails Processingandproducinglanguage Reading:sound-symbolrelationships,word recognition,readingcomprehension Performingmathematicalcalculations Sequencingmovements Performingmovements andgestures tocommand Expressingpositiveemotions Processinginformationina simultaneous,holistic, or gestaltmanner Graspingoverallorganizationorpattern Processingnonverbalstimuli(environmental sounds, speechintonation,complex shapes, anddesigns) Visual-spatialperception Drawinginferences,synthesizinginformation Mathematicalreasoningandjudgment Alignmentofnumeralsincalculations Sustaininga movement orposture Expressingnegative emotions Perceivingemotion FromO'Sullivan SB.Stroke.InO'SullivanSB,Schmitz TJ(eds).Physical Rehabilitation Assessment and Treatment,4thedition.Philadelphia,FADavis, 2001,P 536. Theprocessingof informationinastep-by-stepor detailed fashionallowsforthoroughanalysis.Forthemajorityof people,languageisproducedandprocessedintheleft hemisphere,specifically the frontaland temporal lobes.The leftparietallobeallowsanindividualtorecognizewords andtocomprehend whathasbeen read.In addition,mathematical calculations areperformed intheleftparietal lobe. Anindividualisabletosequenceandperformmovements andgesturesasa resultof afunctioningleftfrontallobe.A finalbehavior assignedto the left cerebralhemisphereisthe expressionof positiveemotions suchashappinessand love. Commonimpairmentsseeninpatientswithlefthemisphericinjuryincludeaninabilitytoplanmotortasks (apraxia);difficulty in initiating,sequencing,and processing atask;difficultyinproducingorcomprehendingspeech; perseverationof speechormotorbehaviors;andanxiousness(O'Sullivan,2001). RightHemisphereFunctions.Therightcerebralhemisphere isresponsiblefor an individual's nonverbal and artisticabilities.Therightsideof the brain allowsindividualsto processinformationinacompleteor holisticfashionwithoutspecificallyreviewingallthedetails.Theindividualis abletograsporcomprehendgeneralconcepts.Visual-perceptualfunctionsincludingeye-handcoordination,spatial relationships,andperceptionof one'spositioninspaceare carriedout in therighthemisphere.Theabilitytocommunicatenonverballyandtocomprehendwhatisbeing expressedisalsoassignedtotherightparietallobe. Nonverbalskillsincludingunderstandingfacialgestures, recognizing visual-spatialrelationships,andbeingawareof bodyimageareprocessedintherightsideof thebrain. Otherfunctionsincludemathematicalreasoningandjudgment,sustainingamovementorposture,andperceiving negativeemotionssuchasangerandunhappiness (O'Sullivan,2001).Specificdeficitsthat canbeobservedin patientswithrighthemispheredamageincludepoorjudgment,unrealisticexpectations,denialofdisabilityor deficits,disturbancesinbodyimage,irritability,and lethargy. HemisphericConnections Even though the twohemispheres of the brainhavediscrete functionalcapabilities,theyperformmanyofthesame actions.Communicationbetweenthetwohemispheresis constant,soindividualscanbeanalyticandyetstillgrasp broadgeneralconcepts.Itispossiblefortherighthandto know what the lefthand isdoing and viceversa.The corpus callosum isa large group ofaxons that connect the right and leftcerebralhemispheresandallowcommunication betweenthetwocortices. Deeper BrainStructures Subcorticalstructuresliedeep withinthebrainand include theinternalcapsule,thediencephalon,andthebasalganglia.Thesestructuresarebrieflydiscussedbecauseof their functionalsignificancetomotor function. InternalCapsule.Alldescendingfibersleavingthe motorareasof thefrontallobetravelthroughtheinternal capsule, a deep structure within the cerebral hemisphere. The internalcapsuleismadeupofaxonsthatprojectfromthe cortextothewhitematterfibers(subcorticalstructures) located below and fromsubcortical structures to the cerebral cortex.Thecapsuleisshapedlikealess-thansign), with ananterior and a posterior limb.The corticospinal tract travelsintheposteriorpartof thecapsuleandallowsinformation to betransmittedfromthecortex tothe brainstemand spinalcord.Alesion withinthisareacancausecontralateral loss ofvoluntary movement and conscious somatosensation, whichistheabilitytoperceivetactileandproprioceptive input. TheinternalcapsuleispicturedinFigure2-6. Diencephalon.Thediencephalonissituateddeep withinthecerebrumandiscomposedof thethalamusand CoronaradiataWhitematterCerebralcortex Corpus\.j.....1:; Putamen

Internal Globus capsule pallidus 14SECTION1FOUNDATIONS j7i Amygdala Mamillary bodySubthalamic AnucleusSubstantianigra R. oculomotor nerve BPonsMedullaPyramidOliveCerebellum FIGURE 2-6.The cerebrum. A,Diencephalon andcerebral hemispheres. B,A deep dissection of the cerebrumshowingtheradiatingnerve fibers,the corona radiata,that conduct signalsin bothdirections between the cerebralcortex andthelower portions of the centralnervous system.(A,FromLundy-EkmanL.Neuroscience:FundamentalsforRehabilitation,2ndedition. Philadelphia,WBSaunders,2002;B,fromGuytonAC.BasicNeuroscience:Anatomyand Physiology,2ndedition.Philadelphia,WBSaunders,1991.) hypothalamus.Thediencephalonistheareawherethe majorsensorytracts(dorsalcolumnsandlateralspinothalamic)andthevisualandauditorypathwayssynapse.The thalamusconsistsofalargecollectionofnucleiand synapses.Inthisway,thethalamusservesasacentralrelay stationforsensoryimpulsestravelingupwardfromother partsof thebodyandbraintothecerebrum.Itreceivesall sensoryimpulsesexceptthoseassociatedwiththesenseof smellandchannelsthemtoappropriateregionsof thecortex forinterpretation.Moreover,thethalamus relays sensory informationtotheappropriateassociationareaswithinthe cortex.Motorinformationreceivedfromthebasalganglia andcerebellumistransmittedtothecorrectmotorregion throughthethalamus.Sensationsof painandperipheral numbness can alsobe identified at the levelof the thalamus. Hypothalamus.Thehypothalamusisagroupof nuclei thatlieatthebaseof thebrain,underneaththethalamus. Thehypothalamusregulateshomeostasis,whichisthe maintenanceofabalancedinternalenvironment.This structureisprimarilyinvolvedinautomaticfunctions, includingtheregulationof hunger,thirst,digestion,body temperature,bloodpressure,sexualactivity,andsleep-wake cycles.Thehypothalamusisresponsibleforintegratingthe functionsofboththeendocrinesystemandtheANS throughitsregulationof thepituitaryglandanditsrelease of hormones. BasalGanglia.Anothergroupof nucleilocatedatthe baseof thecerebrumcomprisethebasalganglia.Thebasal ganglia form a subcortical structure made upof the caudate, putamen, globuspallidus,substantia nigra,and subthalamic nuclei. The globus pallidus and putamen formthe lentiform nucleus,andthecaudateandputamenareknownasthe striatum.Thenucleiofthebasalgangliainfluencethe motor planning areasof the cerebral cortex through various motorcircuits.Primaryresponsibilitiesof thebasalganglia includetheregulationof postureandmuscletoneandthe controlof volitionalandautomaticmovement.Inaddition totheirroleinmotorcontrol,thecaudatenucleusis involvedincognitivefunctions.Themostcommonconditionthatresultsfromdysfunctionwithinthebasalganglia isParkinsondisease.Patients withParkinsondiseaseexhibit bradykinesia (slownessinitiating movement),akinesia(difficultyininitiatingmovement),tremors,rigidity,andposturalinstability.Deathof thecellsinthesubstantianigra, which producesdopamine,hasbeen identifiedasthecause of thisdisease. LimbicSystem.Thelimbicsystemisagroupof deep brain structures in the diencephalon and cortex that includes parts of the thalamus and hypothalamus and a portion of the frontalandtemporallobes.Thehypothalamuscontrols primitiveemotionalreactions,includingrageandfear.The limbicsystemguidestheemotionsthatregulatebehavior andisinvolvedinlearningandmemory.Morespecifically, thelimbic system appears to control memory, pain, pleasure, rage,affection,sexualinterest,fear,and sorrow. Cerebellum Thecerebellumcontrolsbalanceandcomplexmuscular movements.Itislocatedbelowtheoccipitallobeof the cerebrumandisposterior tothebrainstem.It fillstheposteriorfossaof thecranium.Likethecerebrum,italsoconsistsoftwosymmetrichemispheres.Thecerebellumis responsible for theintegration, coordination, and execution of multijointmovements.Thecerebellumregulatestheinitiation,timing,sequencing,and forcegenerationof muscle contractions. It sequencestheorder of musclefiringwhena groupof musclesworktogethertoperformamovement suchassteppingorreaching.Thecerebellumalsoassists withbalanceand posturemaintenance and hasbeen identifiedasacomparatorof actualmotorperformancetothat whichisanticipated.Thecerebellummonitorsandcomparesthemovementrequested,forinstance,thestep,with themovement actuallyperformed (Horak,1991). BrainStem Thebrainstemislocatedbetweenthebaseof thecerebrum andthespinalcordandisdividedintothreesections (Fig.2-7).Movingcephalocaudally,thethreeareasarethe midbrain,pons,andmedulla.Eachof thedifferentareasis responsible for specific functions.The midbrainconnectsthe diencephalon to the pons and actsasa relay station for tracts passingbetweenthecerebrumandthespinalcordor cerebellum.Themidbrainalsohousesreflexcentersforvisual, auditory,andtactileresponses.The ponscontains bundles of axonsthat travelbetweenthecerebellumandtherestof the CNS andfunctionswiththemedulla to regulatethebreath-NeuroanatomyCHAPTER215 ing rate.Italsocontainsreflexcentersthatassistwithorientationof theheadinresponsetovisualandauditorystimulation.Cranialnervenucleicanalsobefoundwithinthe pons, specifically,cranialnerves V through VIII, whichcarry motorandsensoryinformationtoandfromtheface.The medullaisanextensionof thespinalcordandcontainsthe fibertractsthat runthroughthespinal cord.Motor and sensory nuclei forthe neck and mouth regionarelocated within themedulla,aswellasthecontrolcentersforheartandrespirationrates.Reflexcentersforvomiting,sneezing,and swallowingarealsolocated withinthemedulla. Thereticularactivating~ y s t e m isalsosituatedwithinthe brainstem and extends vertically throughout itslength. The systemmaintainsandadjustsanindividual'slevelof arousal,including sleep-wakecycles.Inaddition,thereticular activating system facilitatesthe voluntary and autonomic motor responsesnecessaryforcertainself-regulating,homeostatic functionsandisinvolvedinthemodulation of muscletonethroughoutthebody. SpinalCord Thespinal cordhastwoprimaryfunctions:coordinationof motor informationandmovementpatternsandcommunicationofsensoryinformation.Subconsciousreflexes, includingwithdrawalandstretchreflexes,areintegrated withinthespinalcord.Additionally,thespinalcordprovidesa means of communication betweenthebrainand the peripheral nerves. The spinal cord isa direct continuation of thebrainstem,specificallythemedulla.Thespinalcordis housedwithinthevertebralcolumnandextendsapproximatelytothelevelof thefirstlumbar vertebra.Thespinal cordhastwoenlargements,one that extendsfromthethird cervicalsegmenttothesecondthoracicsegmentand another that extends from the first lumbar to the third sacral Spinal cord ---..... / ( UMldbraln Pons - - - - - ~ /Medulla -----_Brainstem --.Cerebellum FIGURE2-7.Midsagittalviewof thebrain.(RedrawnfromFarberSO.Neurorehabilitation: A Multisensory Approach.Philadelphia,WBSaunders,1982.) 16SECTION1FOUNDATIONS segment.Theseenlargementsaccommodatethegreatnumberof neuronsneededtoinnervatetheupperandlower extremitieslocatedintheseregions.Atapproximatelythe L1level,thespinalcordbecomesacone-shapedstructure calledtheconusmedullaris.Theconusmedullarisiscomposed of sacralspinalsegments.Below thislevel,thespinal cordbecomesamassof spinalnerverootscalledthecauda equina.Thecaudaequinaconsistsof thenerverootsfor spinalnervesL2through55.Figure2-8depictsthespinal cord anditsrelationtothe brain.A thin filament,thefilum terminale,extendsfromthecaudalendof thespinalcord andattachestothe coccyx.Inadditiontothebony protection offeredby the vertebrae,the spinal cord isalsocovered by thesameprotectivemeningealcoveringsasinthebrain. Internal Anatomy Theinternalanatomyof thespinalcordcanbevisualizedin cross-sections and is viewedastwodistinct areas.Figure 2-9, A, illustratestheinternalanatomyof thespinalcord.Likethe brain,thespinalcordiscomposedof grayandwhitematter. Thecenterofthespinalcord,thegraymatter,isdistinguishedby itsH-shapedor butterfly-shapedpattern.Thegray THEBRAIN ~ ~ - - ~Frontallobe ""1'""''''''''''''-_ Motor area Parietallobe Frontallobe Sensory area Occipitallobe ~ Temporallobe M'd,lI,VD; ; ; ~ ; " b , " , mThoracic THESPINAL CORD segment Conus medullaris Lumbar segment QSacral segment Duralsac containing cauda equina and filum terminale FIGURE2-8.Theprincipalanatomicpartsof thenervoussystem.(FromGuytonAC.BasicNeuroscience:Anatomyand Physiology,2nd edition.Philadelphia,WBSaunders,1991.) matter contains cell bodies of motor and sensory neurons and synapses.Theupperportionisknownasthedorsalor posteriorhornandisresponsiblefortransmittingsensorystimuli. The lower portion isreferredtoasthe anterior or ventralhorn (Fig.2-9,B).Itcontainscellbodiesof lowermotorneurons, anditsprimaryfunctionistotransmitmotor impulses.The lateralhom ispresent attheT1toL2levelsandcontainscell bodies of preganglionic sympathetic neurons. It isresponsible forprocessingautonomicinformation.Theperipheryof the spinalcordiscomposedof whitematter.Thewhitematter is composedofsensory(ascending)andmotor(descending) fiber tracts.A tract isa group of nerve fibersthat aresimilar in origin,destination,andfunction.Thesefibertractscarry impulses to and from various areas within the nervous system. Inaddition,thesefibertractscrossover fromone sideof the body to theother at various points within the spinal cord and brain.Therefore,an injurytotherightsideof thespinalcord mayproducea lossof motor or sensory functionon thecontralateralside. Major Afferent (Sensory)Tracts Twoprimaryascendingsensorytractsarepresentinthe whitematterof thespinalcord.Thedorsalorposterior columnscarryinformationaboutpositionsense(proprioception),vibration,two-pointdiscrimination,anddeep touch.Figure2-10showsthelocationof thistract.The fibersof thedorsalcolumnscrossinthebrainstem.Pain and temperature sensations aretransmitted in the spinothalamictractlocatedanterolaterallyinthespinalcord(see Fig.2-10).Fibersfromthistractenterthespinalcord, synapse,andcrosswithinthreesegments.Sensory informationmustberelayedtothethalamus.Touchinformation has tobeprocessed by the cerebral cortex for discrimination tooccur.Lighttouchandpressuresensationsenterthe spinalcord,synapse,andarecarriedinthedorsalandventralcolumns. Major Efferent(Motor)Tract Thecorticospinaltractistheprimarymotorpathwayand controlsskilledmovementsof theextremities.Thistract originatesinthefrontallobefromtheprimaryandpremotorcorticesandcontinuesthroughinterconnectionsand various synapses, finally to synapse on anterior horn cellsin thespinalcord.Thistract alsocrossesfromone sidetothe otherinthebrainstem.AcommonindicatorofcorticospinaltractdamageistheBabinskisign.Totestforthis sign,thecliniciantakesa bluntobjectsuchasthe back of a pen andrunsit along thelateralborder of the patient's foot (Fig.2-11).Thesignispresentwhenthegreattoeextends andtheothertoessplay.Thepresenceof aBabinskisign indicatesthatdamagetothecorticospinaltracthas occurred. Other DescendingTracts Otherdescendingmotorpathwaysthataffectmuscletone aretherubrospinal,lateralandmedialvestibulospinal, 17NeuroanatomyCHAPTER2 Dorsal grayDorsalwhite horncolumns Lateralwhitecolumn\.... POSTERIOR ./..c",("l.X'8;:;;i:[I,'/Ventralgrayhorn ---__..-_ Dorsalroot filaments Ventralwhite column Spinalpiamater Subarachnoid space Spinalarachnoid Spinalnerve Spinalduramater AANTERIOR GRAY MATTERWHITEMATTER Dorsalhorn/{'.Dorsalcolumn LateralhornI (\ - r"/)ILateralcolumn Ventralhorn.......,,\\?'{lPiocJ::,!-;b0Anterior column B FIGURE2-9.Thespinalcord.A,Structuresof thespinalcordanditsconnectionswiththe spinalnerve by way of the dorsalandventralspinalroots.Note also thecoverings of the spinal cord, the meninges. B,Cross-sectionof thespinalcord.The central gray matter isdividedinto horns anda commissure.The white matter is divided into columns.(A,From Guyton AC.Basic Neuroscience: Anatomy and Physiology,2ndedition.Philadelphia,WBSaunders,1991.) tectospinal,and medialand lateralreticulospinaltracts.Themal extensor muscles.Regulation ofmuscle tone in the neck rubrospinaltractoriginatesintherednucleusof themid andupperbackisafunctionof themedialvestibulospinal brain andterminatesin theanterior horn, whereitsynapsestract.Themedialreticulospinaltractfacilitateslimbextenwithlowermotorneuronsthatprimarilyinnervatethesors, whereasthe lateral reticulospinal tract facilitatesflexors upperextremities.Fibersfromthistractfacilitateflexorandinhibitsextensormuscleactivity.Thetectospinaltract motorneuronsandinhibitextensormotorneurons.providesfororientationof theheadtowardasoundora Proximalmusclesareprimarilyaffected,althoughthetractmoving object. does exhibit some influence over more distal muscle groups. Anterior HornCellTherubrospinaltracthasbeensaidtoassistinthecorrectionof movementerrors.ThelateralvestibulospinaltractAn anterior horn cell isa large neuron located in the gray matassistsinposturaladjustmentsthroughfacilitationof proxi- ter of thespinal cord.Ananterior horn cellsends out axons 18SECTION1FOUNDATIONS Dorsalcolumns / \ LateralFasciculus gracilisPosterior fissure Anterior corticospinal tract temperature(fibers scattered) painandReticulospinaltract Tectospinal tract Anterior median fissure FIGURE2-10.Cross-sectionofthespinalcordshowingtracts.(FromGouldBE. Pathophysiology for theHealth-Related Professions.Philadelphia,WB Saunders,1997.) corticospinal tract descending toskeletal muscle for voluntary movement Rubrospinaltract descending for posture and muscle coordination Lateral spinothalamic tract ascending for A B FIGURE2-11.A,Strokingfromtheheelto theballof the foot alongthelateralsole,thenacrosstheballof the foot,normally causes the toes to flex. B,Babinskisign inresponse to the same stimulus.Incorticospinaltractlesions,orininfantslessthan 6monthsold,thebigtoeextends,andtheother toesfanoutward.(FromLundy-EkmanL.Neuroscience:Fundamentalsfor Rehabilitation,2nd edition.Philadelphia,WB Saunders,2002.) Fasciculus cuneatus Posterior spinocerebellar tract Anterior spinocerebellar tract ascending from proprioceptors inmuscle andtendons for position sense Vestibulospinal tract throughtheventraloranteriorspinalroot;theseaxons eventuallybecomeperipheralnervesandinnervatemuscle fibers.Thus,activationof ananteriorhorncellstimulates skeletal muscle contraction. Alpha motor neurons area type of anterior horn cellthat innervates skeletal muscle.Because of axonal branching, severalmuscle fiberscan be innervated byoneneuron.Amotorunitconsistsof analphamotor neuronandthemusclefibersitinnervates.Gammamotor neuronsarealsolocatedwithintheanteriorhorn.These motor neuronstransmitimpulsestotheintrafusalfibersof themusclespindle. MuscleSpindle Themusclespindleisthesensoryorganfoundinskeletal muscleand iscomposed of motor andsensory endingsand musclefibers.Thesefibersrespondtostretchandtherefore providefeedbacktotheeNS regardingthemuscle's length. Theeasiestwaytoconceptualizehowthemusclespindlefunctionswithinthenervoussystemistoreviewthe stretchreflexmechanism.Stretchordeeptendonreflexes caneasilybefacilitatedinthebiceps,triceps,quadriceps, andgastrocnemiusmuscles.If a sensory stimulussuch asa taponthepatellar tendonisappliedto themuscleandits spindle,theinput willenter through thedorsalroot of the spinalcordtosynapseontheanteriorhorncell(alpha motor neurons).Stimulation of theanterior horn cellelicitsamotorresponse,reflexcontractionof thequadriceps (extensionof theknee),asinformationiscarriedthrough theanterior root totheskeletal muscle.An important note aboutstretchordeeptendonreflexesisthattheiractivationandsubsequentmotorresponsecanoccurwithout highercorticalinfluence.Thesensoryinputcominginto thespinalcorddoesnothavetobetransmittedtothe : : forinterpretation.Thishasclinicalimplications : : :auseitmeansthatapatientwithacervicalspinalcord :-,''';ITcancontinuetoexhibitlowerextremitydeepten:::-:reHexesdespitelowerextremity paralysis. =eripheralNervousSystem -:-:-,0'peripheralnervoussystem(PNS)consistsof thenerves :ding toandtromtheCNS,includingthecranialnerves :'cmg thebrain stem and thespinal rootsexiting the spinal ::manyof whichcombinetoformperipheralnerves. -:-:-:O'senervesconnect theCNS functionally withthe restof =.-,0'bodythroughsensory andmotor impulses.Figure2-12 =-: 2\'idesa schematic representation of thePNSand itstranc::ontotheCNS. TI1ePNSisdividedintotwoprimarycomponents:the :: :natic(body)nervoussystemandtheANS.Thesomatic :\-oluntarynervoussystemisconcerned withreactionsto : stimulation.Thissystemisunder consciouscontrol NeuroanatomyCHAPTER219 and isresponsibleforskeletalmusclecontraction by wayof the31pairsof spinalnerves.Bycontrast,theANSisan involuntary systemthat innervates glands,smooth (visceral) muscle,andthemyocardium.Theprimaryfunctionof the ANSistomaintainhomeostasis,anoptimalinternalenvironment.Specific functionsincludetheregulationof digestion,circulation,andcardiacmusclecontraction. SomaticNervousSystem WithinthePNSare12pairsof cranialnerves,31pairsof spinalnerves,andthegangliaor cellbodiesassociatedwith thecranialandspinalnerves.Thecranialnervesarelocated in thebrain stem and can beeither sensory or motor nerves. Primaryfunctionsof thecranialnervesincludeeyemovement,smell,sensationperceivedbythefaceandtongue, andinnervationof thesternocleidomastoidandtrapezius muscles.SeeTable2-2foramoredetailedlistof cranial nervesandtheir major functions. eNS Brain Sympathetic chainganglion Pain receptors Sensory neuron Nerve bundle (fascicle) Motor neuron Motor endplate FIGURE2-12.Schematicrepresentationof theperipheralnervoussystemandthetransition to the centralnervoussystem. 20SECTION1FOUNDATIONS ~CranialNerves NumberNameFunctionConnectiontoBrain IOlfactorySmellInferior frontallobe IIOpticVisionDiencephalon IIIOculomotorMoveseyeup,down,medially;Midbrain(anterior) IVTrochlear raisesupper eyelid;constricts Moves eyemedially anddown pupil Midbrain(posterior) VTrigeminalFacialsensation,chewing,sensationPons (lateral) VIAbducens fromtemporomandibular joint Abducts eye VIIFacialFacialexpression,closes eye,tears, VIIIVestibulocochlear salivation,taste Sensationof headpositionrelativeto IXGlossopharyngeal gravity andheadmovement; Swallowing,salivation,taste hearing Medulla XVagusRegulates viscera,swallowing,speech,tasteMedulla XIAccessoryElevates shoulders,turnsheadSpinalcordandmedulla XIIHypoglossalMoves tongueMedulla Betweenponsandmedulla Betweenpons andmedulla Betweenpons andmedulla FromLundy-EkmanL.Neuroscience:Fundamentalsfor Rehabilitation,2ndedition.Philadelphia,WBSaunders,2002,p 299. Thespinalnervesconsistof 8cervical,12thoracic,5 lumbar,and5 sacralnervesand1 coccygealnerve.Cervical spinalnervesC 1 throughC7exitabovethecorresponding vertebrae.Becausethereareonly7cervicalvertebrae,the C8 spinal nerve exits above the Tl vertebra.From that point on,eachsucceedingspinalnerveexitsbelowitsrespective vertebra.Figure 2-13showsthe distributionandinnervation of theperipheralnerves. Spinalnerves,consistingof sensory(posteriorordorsal root)and motor (anterioror ventralroot)components,exit the intervertebral foramen. The region of skin innervated by sensoryafferentfibersfromanindividualspinalnerveis calledadermatome.Myotomesareagroupof musclesinnervatedbyaspinalnerve.Oncethroughtheforamen,the spinalnervedividesintotwoprimaryrami.Thisdivision represents the beginning of the PNS. The dorsal or posterior ramiinnervatetheparavertebralmuscles,theposterior aspectsof thevertebrae,and the overlying skin.The ventral oranteriorprimaryramiinnervatetheintercostalmuscles, the musclesand skin inthe extremities, and the anterior and lateraltrunk. The12pairsof thoracicnervesdonotjoinwithother nervesand maintaintheir segmental relationship.However, theanteriorprimaryramiof theotherspinalnervesjoin togethertoformlocalnetworksknownasthecervical, brachial,andlumbosacralplexuses(Guyton,1991).The readerisgivenonlyabriefdescriptionofthesenerve plexuses,because a detailed description of thesestructures is beyondthescopeof thistext. CervicalPlexus.The cervicalplexusiscomposedof the C 1 throughC4 spinal nerves.Thesenervesprimarily innervatethedeepmusclesof theneck,thesuperficialanterior neckmuscles,thelevatorscapulae,andportionsofthe trapeziusandsternocleidomastoid.Thephrenicnerve,one of thespecificnerveswithinthecervicalplexus,isformed frombranchesof C3through C5.Thisnerveinnervatesthe diaphragm,theprimarymuscleof respiration,andisthe onlymotorandmainsensorynerveforthismuscle (Guyton,1991).Figure2-14identifiescomponentsof the cervicalplexus. BrachialPlexus.TheanteriorprimaryramiofC5 through Tl formthe brachial plexus.The plexusdividesand comestogether severaltimes,providing muscleswithmotor andsensoryinnervationfrommorethanonespinalnerve root level.Thefiveprimary nervesof thebrachialplexusare themusculocutaneous,axillary,radial,median,andulnar nerves.Figure2-15depictstheconstituencyof thebrachial plexus. These fiveperipheral nervesinnervate the majority of theupperextremitymusculature,withtheexceptionof the medialpectoralnerve(C8),whichinnervatesthepectoralis muscles;thesubscapularnerve(C5andC6),whichinnervatesthesubscapularis;andthethoracodorsalnerve(C7), whichsuppliesthelatissimusdorsimuscle (Guyton,1991). The musculocutaneous nerve innervates the forearmflexors.Theelbow, wrist,and fingerextensorsareinnervatedby theradialnerve.Themediannervesuppliestheforearm pronatorsandthewristandfingerflexors,anditallows thumbabductionandopposition.Theulnarnerveassists the median nervewithwrist and fingerflexion,abductsand adductsthefingers,andallowsforoppositionof thefifth finger(Guyton,1991). Lumbosacral Plexus.Although some authors discussthe lumbar and sacral plexuses separately, they arediscussed here asoneunitbecausetogetherthey innervatelower extremity musculature.Theanteriorprimaryramiof L1through53 formthelumbosacralplexus.Thisplexusinnervatesthe musclesof thethigh,lowerleg,andfoot.Thisplexusdoes notundergothesameseparationandreunitingasdoesthe brachialplexus.Thelumbosacralplexushaseightroots, whicheventually formsix primary peripheral nerves:obturator,femoral,superiorgluteal,inferiorgluteal,common peroneal,andtibial.Thesciaticnerve,whichisfiequently 21NeuroanatomyCHAPTER2 DERMATOMESPERIPHERAL NERVESDERMATOMES Pos:erior ramiof cervical 'XCervical cutaneous--\. l' _/"""'>Supraclavicular ------, -'T,' " \Axillary----____, IX-" Intercostobrachial cutaneous l:rt+r-- Lateralbrachialcutaneous III t-t-- Medialbrachialcutaneous ,/,JI\Anterior thoracicrami II YI \Posterior brachial cutaneous --I"IJ \Lateralthoracicrami---,II Posterior thoracicrami1\\1\ II\y!Medial antebrachialI \ \iii! I' Posterior lumbar rami I,"\'Musculocutaneous; II,/\\ \\ Posterior antebrachial cutaneous' .-Y,I}1 /,:\\,,iliOingUinal/r1 J 'II' >:UlnarV/r'NiI \ \ Radial,JI I I!I,\ldtf)Lumboinguinal't[ufl\ "\ , ,I\ \ ,'\ \\IPosterior sacralramiI" \\Lateralfemoralcutaneous!IV'. Anterior femoralcutaneousI / \ObturatorI I r! k)1Posterior femoral cutaneous/\I 1\/'f.."\1I ' . IC!, )I, \/:ommonperoneal!I V'I\;\f\/1\\(1I!'J S'Ph"o","\s, II(i )Deep peroneal/",j\J.J\ FIGURE2-13.Dermatomesandcutaneousdistributionofperipheralnerves.(FromLundyEkmanL.Neuroscience:FundamentalsforRehabilitation,2ndedition.Philadelphia,WB Saunders,2002.) discussedinphysicaltherapy practice,isactuallycomposedbecomespartof aperipheralnerveandinnervatesamotor ofthecommonperonealandtibialnervesencasedinaendplateinamuscle.Thesensoryneuron,ontheother sheath.Thisnerveinnervatesthehamstringsandcauseshiphand, hasadendritethat originatesintheskin,muscletenextensionandkneeflexion.Thesciaticnerveseparatesintodon, or Golgitendon organ andtravelsallthe way to itscell itscomponentsjustabovetheknee(Guyton,1991).Thebody, which islocated in the dorsal root ganglion within the lumbosacralplexusisshown inFigures2-16and2-17.intervertebralforamen(Fig.2-18).Golgitendonorgansare PeripheralNerves.Twomajortypesof nervefibersareencapsulatednerveendingsfoundatthemusculotendinous contained in peripheral nerves:motor (efferent)and sensoryjunction.Theyaresensitivetotensionwithinmuscleten(afferent)fibers.Motorfibershavealargecellbodywithdonsandtransmitthisinformationtothespinalcord.The multiple brancheddendrites and a long axon.The cell bodyaxontravelsthroughthedorsal(posterior)rootof aspinal and the dendrites arelocated within the anterior horn of thenerveandinto thespinalcordthrough thedorsalhorn. The spinalcord.Theaxonexitstheanteriorhornthroughaxonmayterminateatthispoint,or itmay enter thewhite thewhitematterandislocatedwithother similaraxonsinmatterfibertractsandascendtoadifferentlevelinthe theanteriorroot,whichislocatedoutsidethespinalcordspinalcordorbrainstem.Thus,asensoryneuronsends intheintervertebralforamen.Theaxontheneventuallyinformationfromtheperiphery tothespinalcord. 22SECTION1FOUNDATIONS Lesseroccipital-ToGreat auricular-To sternocleidomastoid To levator scapulaeTransversecutaneous nerveof neck To levator scapulae-----r--7''-,/ To scalenusmedius -------;h"'---,/ Tolongus capitis and longus colli To longus capitis,longus colli, andscalenusmedius To geniohyoid _____ To thyrohyoid To longuscolli Phrenic nerve Supraclavicular FIGURE2-14.Thecervicalplexusanditsbranches.(FromGuytonAC.Basic Neuroscience: Anatomy and Physiology,2ndedition.Philadelphia,WBSaunders,1991.) Dorsalscapularnerve To phrenicnerve Suprascapularnerve Nerveto subclavius Lateralpectoralnerve Lateralcord----,< Museu locutaneous nerve Radialnerve nerve Lower {f----FromC.4 C.5 To scaleni C.6 To scaleni To scaleni ,,"--_-- Long thoracic nerve C.B To scaleni T.1 FromT.2 Firstintercostal nerve Medial pectoralnerve subscapularnerveMedial MedialcutaneousMedialcutaneous cord Upper subscapular nerveof forearmnerveof armnerve FIGURE2-15.Thebrachialplexusanditsbranches.(FromGuytonAC.BasicNeuroscience: Anatomy and Physiology,2ndedition.Philadelphia,WBSaunders,1991.) Neuroanatomy CHAPTER2 23 L.l From12th thoracic L.2 L.3 Lateralcutaneous of thigh LA To sacralplexus ::"e"""',oralnerve FIGURE 2-16.The lumbar plexus and its branches, especially the 'emoralnerve.(FromGuytonAC.BasicNeuroscience:Anatomy 3.ndPhysiology,2ndedition.Philadelphia,WB Saunders,1991.) Superior glutealnerve~Inferior glutealnerve Common peroneal nerve Tibialnerve Autonomic NervousSystem Functionsof theautonomicnervoussystem(ANS)includethe regulationof circulation,respiration,digestion,metabolism, secretion,bodytemperature,andreproduction.ControlcentersfortheANSarelocatedinthehypothalamusandthe brainstem.TheANSiscomposedof motor neuronslocated withinspinalnervesthatinnervatesmoothmuscle,cardiac muscle,andglands,whicharealsocalledeffectorsortarget organs.TheANSisdividedintothesympatheticandparasympatheticdivisions.Boththesympatheticandparasympatheticdivisionsinnervateinternalorgans,useatwo-neuron pathway and one-ganglion impulseconduction, and function automatically. Autoregulation isachievedby integrating informationfromperipheralafferentswithinformationfrom receptorswithintheCNS.Thetwo-neuronpathway (preganglionicandpostganglionicneurons)providestheconnection fromtheCNStotheautonomic effector organs.Cellbodies of thepreganglionicneuronsarelocatedwithinthebrainor spinalcord.ThemyelinatedaxonsexittheCNSandsynapse withcollectionsof postganglioniccellbodies.Unmyelinated axonsfromthepostganglionicneuronsultimatelyinnervate theeffector organs(Farber,1982). LA L.5 S.l S.2 S.3 SA S.5 Co. Tolevator ani,coccygeus,and sphincter aniexternus FIGURE 2-17,The sacral plexus andits branches, especially the sciatic nerve.(From Guyton AC. Basic Neuroscience: Anatomy and Physiology,2ndedition.Philadelphia,WB Saunders,1991.) 24SECTION1FOUNDATIONS Dura mater'l Arachnoid' Meninges PiamaterI Dorsal ".ramusVentral '"~ " ~ _ ~ ' ramus ' " "'\ , '\;:... "'il \\~ j Ventral root Spinal cord Vertebral body Rami FIGURE2-18.Spinalregion.Thespinalnerveisformedof axonsfromthedorsalandventralroots.Thebifurcationofthe spinalnerveintodorsalandventralramimarksthetransition fromthespinaltotheperipheralregion.(FromLundy-EkmanL. Neuroscience:FundamentalsforRehabilitation,2ndedition. Philadelphia,WBSaunders,2002.) The sympathetic fibersof the ANSarisefromthethoracic andlumbarportionsof thespinalcord.Axonsof preganglionicneuronsterminateineitherthesympatheticchainor theprevertebralganglialocatedintheabdomen.TIlesympathetic division ofthe ANSassiststhe individual in responding tostressfulsituationsandisottenreferredtoasthefight-orflightresponse.Sympatheticresponseshelptheindividualto prepare to cope with the perceived stimulus by maintaining an optimalbloodsupply.Activationof thesympatheticsystem stimulatessmoothmuscleinthebloodvesselstocontract, therebycausingvasoconstriction.Norepinephrine,also known asnoradrenaline, isthe major neurotransmitter responsibleforthisaction.Consequently,heart rateand bloodpressureareincreasedasthebody preparesfora fightor tofleea dangeroussituation.Bloodflowtomusclesisincreasedby being divertedfromthe gastrointestinaltract. Theparasympatheticdivisionmaintainsvitalbodily functionsorhomeostasis.Theparasympatheticdivision receivesitsinformationfromthebrainstem,specifically cranialnervesIII(oculomotor),VII(facial),IX(glossopharyngeal),andX(vagus),andfromlowersacralsegments of thespinalcord.Thevagusnerveisaparasympathetic preganglionicnerve.Motorfiberswithinthevagusnerve innervatethemyocardiumandthesmoothmusclesof the lungsanddigestivetract.Activationof the vagusnervecan producethefollowingeffects:bradycardia,decreasedforce ofcardiacmusclecontraction,bronchoconstriction, increasedmucusproduction,increasedperistalsis,and increasedglandularsecretions.Efferentactivationofthe sacralcomponentsresultsinemptyingof thebowelsand bladderandarousalof sexualorgans.Acetylcholineisthe chemical transmitter responsible for sending nervous system impulsestoeffectorcellsintheparasympatheticdivision. Acetylcholine isusedfor both divisions atthe preganglionic synapseanddilatesarterioles.Thus,activationofthe parasympatheticdivisionproducesvasodilation.Whenan individualiscalm,parasympatheticactivitydecreasesheart rateandbloodpressureandsignalsareturnof normalgastrointestinalactivity.Figure2-19showstheinfluenceof the sympatheticandparasympatheticdivisionsoneffector organs(Farber,1982;Lundy-Eknlan,2002). TheCNSalsoexertsinfluenceovertheANS.The regionsmostcloselyassociatedwiththiscontrolarethe hypothalamus,whichregulatesfunctionssuchasdigestion, andthe medulla, which controls heart and respirationrates. Brainstem Parasympathetic fibers - CRANIAL NERVESIII,VII, IX,X ]-.-c:--.LEGS-l } Phrenicnerve to diaphragm RESPIRATION Intercostal muscles RESPIRATION Sympathetic nervous system HEART BLOODVESSELS TEMPERATURE Parasympathetic nerves BOWEL BLADDER EXTERNAL GENITALIA FIGURE 2-19.Functionalareasof the spinalcord.(FromGould BE.PathophysiologyfortheHealth-RelatedProfessions. Philadelphia,WBSaunders,1997.) ICerebralCirculation I!;\finalareathatmustbereviewedwhendiscussingthe II'fjnervoussystemisthecirculationtothebrain.Thecells : within the brain completely depend on a continuous supplyIof bloodforglucoseandoxygen.Theneuronswithinthe brainareunabletocarryout glycolysisandtostoreglycogen.It isthereforeabsolutelyessentialthattheseneurons receiveaconstantsupplyofblood.Knowledgeofcerebrovascular anatomyisthebasisforunderstandingtheclini.::almanifestations,diagnosis,andmanagementof patients who have sustained cerebrovascular accidentsand traumatic .'" ::lraInInJunes. Anterior Circulation ,-\11arteriestothebrainarisefromtheaorticarch.Thetlrst :najorarteriesascendinganteriorlyandlaterallywithinthe neckarethecommoncarotidarteries.Thecarotidarteries dreresponsibleforsupplying the bulk of thecerebrum with .::irculation.Therightandleftcommoncarotidarteries :,iturcatejustbehindtheposteriorangleofthejawto Jecometheexternalandinternalcarotids.Theexternal .::arotidarteriessupply the face,whereastheinternal carotids e:1terthecraniumandsupplythecerebralhemispheres, :ncluding the frontal lobe, the parietallobe,and parts of the :emporallobe.Inaddition,theinternalcarotidarterysup::-liestheoptic nervesand the retinaof theeyes.At the base :t' thebrain,theinternalcarotidbifurcatesintotheright dodleftanteriorandmiddlecerebralarteries.Themiddle :erebralarteryisthelargestof thecerebralarteriesandis ::lOstoften occluded.It isresponsibleforsupplying thelate:alsurfaceof thebrainwithbloodandalsothedeeppor:'ons of thefrontalandparietallobes.Theanterior cerebral d:terysuppliesthesuperiorborderof thefrontalandparie:allobes.Boththemiddlecerebralarteryandtheanterior :erebralarterymakeupwhatiscalledtheanteriorcircula::ontothebrain.Figures2-20and2-21depictthecerebral : l:culation. Posterior Circulation Theposteriorcirculationiscomposedof thetwovertebral d:teries,whicharebranchesof the subclavian.The vertebral d::eriessupply blood to thebrain stemand cerebellum.The '.-e:tebralarteriesleavethebaseof theneck and ascendpos:eriorlytoentertheskullthroughtheforamenmagnum. --=-:-:etwovertebralarteriesthenunitetoformthebasilar .:.::ery.Thebasilararterysuppliesthebrainstemandthe ::-,edialportion of thetemporaland occipital lobeswithcir: .::ation.Thisarteryalsobifurcatestoformtherightand e:1posteriorcerebralarteries.Thetwoposteriorcerebral d::eriessupply blood totheoccipitalandtemporallobes. Theanteriorandposteriorcommunicatingarteries, C''-:''.icharebranchesof thecarotidandbasilararteries,are .== :erconnectedatthebaseof thebrainandformthecircle : :' \\illis.Thisconnectionof blood vesselsprovidesapro-e::ivemechanismtothestructureswithinthebrain. NeuroanatomyCHAPTER225 Anterior cerebral artery Intemal carotid artery Anterior communicating artery Posterior communicating artery Posterior cerebral artery Basilar artery FIGURE2-20.Fromanteriortoposterior,thearteriesthatform thecircleofWillisaretheanteriorcommunicating,twoanterior cerebral,twointernalcarotid,twoposteriorcommunicating,and twoposteriorcerebralarteries.(FromLundy-EkmanL.Neuroscience: Fundamentals for Rehabilitation, 2nd edition. Philadelphia, WB Saunders, 2002.) Becauseof thecircleof Willis,failureor occlusionof one cerebral artery does not critically decrease blood flow to that region.Consequently,theocclusioncanbecircumvented or bypassedtomeetthenutritionaland metabolicneedsof cerebraltissue. REACTIONTOINJURY WhathappenswhentheCNSorthePNSisinjured?The CNS and the PNS areprone to different typesof injury,and eachsystemreactsdifferently.WithintheCNS,artery obstructionof sufEcientdurationproducescellandtissue deathwithinminutes.Neuronsthatdiebecausetheyare deprivedof oxygendonot possessthecapacitytoregenerate.Neuronsinthevicinityof damagearealsoatriskof injurysecondarytothereleaseof glutamate,anexcitatory neurotransmitter.Atnormallevels,glutamateassistswith CNSfunctions;however,athigher levelsglutamatecanbe toxic to neurons and can promote neuronal death. The presenceof excessiveglutamatealsofacilitatescalciumrelease, whichultimately produces a cascade of events including the liberation of calcium-dependent digestiveenzymes,cellular edema,cellinjury,anddeath(Lundy-Ekman, 2002). Changeswithintheneuronsthemselvesarenotevident for12to24hours.By24to36hours,thedamagedarea SECTION1FOUNDATIONS 26 Anterior cerebral artery A Anterior cerebral artery MiddlecerebralarteryB FIGURE2-21.Thelargecerebralarteries:anterior,middle,and posterior.(FromLundy-EkmanL.Neuroscience: Fundamentals for Rehabilitation,2ndedition.Philadelphia,WBSaunders,2002.) becomessoftandedematous.Liquefactionandcavitation begin, and thearea of necrotic tissueiseventually converted intoacyst.Intime,theinfarctwilleventuallyretract,and the cystic cavity willby surrounded by a glialscar.The damaged neurons willnot be replaced, and theoriginal function of thearea willbelost(Branch,1987). Nearby undamagedaxonsdemonstratecollateralsprouting4to5daysafterinjury.Thesesproutsreplacethedamagedsynapticarea,thusincreasinginputtoother neurons. Although thesecollateral sprouts do not replaceoriginal circuits,they do developfromsystemsmost closely associated withtheinjuredarea. Conversely,peripheralnerveinjuriesoftenresultfrom means other than vascular compromise.Common causes of peripheral nerve injuries include stretching, laceration,compression,traction,disease,chemicaltoxicity,and nutritional deficiencies.The responseof a peripheral nerve to the injury isdifferentfromthatintheeNS.Ifthecellbodyis destroyed,regeneration isnot possible.Theaxon undergoes necrosisdistaltothe siteof injury,themyelin sheath begins topullaway,andtheSchwanncellsphagocytizethearea, producing walleriandegeneration(Fig.2-22).If thedamage totheperipheralnerveisnottoosignificantandoccurs only to theaxon,regenerationispossible. Axonal sprouting fromthe proximal end of thedamaged axon can occur.The axonreg