About Brain Injury: A Guide to Brain Anatomy

About Brain Injury: A Guide to Brain AnatomyInformation from http://www.waiting.com, © 1997-2002, Becca, Ltd.34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgBrain Anatomy DefinitionsBrainstem: The lower extension of the brain where itconnects to the spinal cord. Neurological functions located inthe brainstem include those necessary for survival (breathing,digestion, heart rate, blood pressure) and for arousal (beingawake and alert). Most of the cranial nerves come from thebrainstem. The brainstem is the pathway for all fiber tractspassing up and down from peripheral nerves and spinal cordto the highest parts of the brain.Cerebellum: The portion of the brain (located at the back) which helps coordinate movement(balance and muscle coordination). Damage may result in ataxia, which is a problem of musclecoordination. Ataxia can interfere with a person’s ability to walk, talk, eat, and to perform otherself-care tasks.Frontal Lobe: Front part of the brain; involved in planning, organizing, problem solving, selectiveattention, personality and a variety of “higher cognitive functions” including behavior and emotions.The anterior (front) portion of the frontal lobe is called the prefrontal cortex. It is veryimportant for the “higher cognitive functions” and the determination of the personality.Informationcopyrighted byauthors listed andmay not bephotocopied formass distribution.The posterior (back) of the frontal lobe consists of the premotor and motor areas. Nervecells that produce movement are located in the motor areas. The premotor areas serve tomodify movements.The frontal lobe is divided from the parietal lobe by the central culcus.Occipital Lobe: Region in the back of the brain which processes visual information. Not onlyis the occipital lobe mainly responsible for visual reception, it also contains association areas thathelp in the visual recognition of shapes and colors. Damage to this lobe can cause visual deficits.Parietal Lobe: One of the two parietal lobes of the brain located behind the frontal lobe at thetop of the brain.

Parietal Lobe, Right - Damage to this area can cause visuo-spatial deficits (e.g., the patientmay have difficulty finding their way around new, or even familiar, places).Parietal Lobe, Left - Damage to this area may disrupt a person’s ability to understand spokenand/or written language.34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgThe parietal lobes contain the primary sensory cortex which controls sensation (touch,pressure). Behind the primary sensory cortex is a large association area that controls finesensation (judgment of texture, weight, size, and shape).Temporal Lobe: There are two temporal lobes, one on each side of the brain located at about the levelof the ears. These lobes allow a person to tell one smell from another and one sound from another.They also help in sorting new information and are believed to be responsible for short-term memory.Right Lobe - Mainly involved in visual memory (i.e., memory for pictures and faces).Left Lobe - Mainly involved in verbal memory (i.e., memory for words and names).About Brain Injury:The Areas of the Brain, Their Function, & Associated Signs & SymptomsInformationcopyrighted byauthors listed andmay not bephotocopied formass distribution.Brain StructureCerebral CortexLeft HemisphereFunctionThe outermost layer of the cerebralhemisphere which is composed of graymatter. Cortices are asymmetrical.Both hemispheres are able to analyzesensory data, perform memoryfunctions, learn new information,form thoughts and make decisions.Sequential Analysis: systematic,logical interpretation of information.Interpretation and production ofsymbolic information: language,mathematics, abstraction and reasoning.Memory stored in a language format.Associated Signs andSymptoms

34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgH o l i s t i c F u n c t i o n i n g :processing multi-sensory inputsimultaneously to provide“holistic” picture of one’senvironment. Visual spatial skills.Holistic functions such as dancingand gymnastics are coordinatedby the right hemisphere. Memoryis stored in auditory, visual andspatial modalities.Corpus CallosumConnects right and left hemisphereto allow for communicationbetween the hemispheres. Formsroof of the lateral and thirdventricles.Damage to the CorpusCallosum may result in “SplitBrain” syndrome.Frontal LobeCognition and memory. Prefrontalarea: The ability to concentrateand attend, elaboration ofthought. The “Gatekeeper”;( j u d g m e n t , i n h i b i t i o n ) .Personality and emotionaltraits.Movement:Motor Cortex(Brodman’s): voluntary motoractivity.Premotor Cortex: storageof motor patterns and voluntaryactivities. Language: motorspeech.• Impairment of recentmemory, inattentiveness,inability to concentrate,behavior disorders, difficultyin learning new information.L a c k o f i n h i b i t i o n(inappropriate social and/orsexual behavior). Emotionallability. “Flat” affect.• Contralateral plegia, paresis.• Expressive/motor aphasia.Informationcopyrighted byauthors listed andmay not bephotocopied formass distribution.Parietal LobeProcessing of sensory input,sensory discrimination.Body orientation.Primary/ secondary somaticarea.• Inability to discriminatebetween sensory stimuli.• Inability to locate andrecognize parts of the body(Neglect).• Severe Injury: Inability torecognize self.• D i s o r i e n t a t i o n o fenvironment space.• Inability to write.

Occipital LobePrimary visual reception area.Primary visual association area:Allows for visual interpretation.• Primary Visual Cortex: loss ofvision opposite field.• Visual Association Cortex:loss of ability to recognizeobject seen in opposite field ofvision, “flash of light”, “stars”.34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgTemporal LobeAuditory receptive area andassociation areas.Expressed behavior.• Hearing deficits.• Agitation, irritability, childishbehavior.• Receptive/ sensory aphasia.Language: Receptive speech.Memory: Information retrieval.Limbic SystemOlfactory pathways:Amygdala and their differentpathways.• Loss of sense of smell.• Agitation, loss of controlof emotion. Loss of recentmemory.Hippocampi and their differentpathways.Limbic lobes: Sex, rage, fear, andemotions. Integration of recentmemory, biological rhythms.Hypothalamus.Basal GangliaSubcortical gray matter nuclei.Processing link between thalamusand motor cortex. Initiation anddirection of voluntary movement.Balance (inhibitory), Posturalreflexes.• Movement disorders:chorea, tremors at rest andwith initiation of movement,abnormal increase in muscletone, difficulty initiatingmovement.Informationcopyrighted byauthors listed andmay not bephotocopied formass distribution.ThalamusPart of extrapyramidal system:regulation of automatic movement.Processing center of the cerebralcortex. Coordinates and regulates allfunctional activity of the cortex viathe integration of the afferent inputto the cortex (except olfaction).Contributes to affectual expression.• Parkinson’s.• A l t e r e d l e v e l o fconsciousness.• Loss of perception.• Thalamic syndrome -spontaneous pain oppositeside of body.

34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgHypothalamusIntegration center of AutonomicNervous System (ANS): Regulationof body temperature and endocrinefunction.A n t e r i o r H y p o t h a l a m u s :parasympathetic activity (maintenancefunction).Posterior Hypothalamus: sympatheticactivity (“Fight” or “Flight”, stressresponse.• Hormonal imbalances.• Malignant hypothermia.Inability to controltemperature.• Diabetes Insipidus (DI).Inappropriate ADH• (SIADH). Diencephalicdysfunction: “neurogenicstorms”.Behavioral patterns: Physical expressionof behavior.Appestat: Feeding center.Pleasure center.Internal Capsule Motor tracts. Contralateral plegia (Paralysisof the opposite side of thebody).Reticular ActivatingSystem (RAS)Responsible for arousal fromsleep, wakefulness, attention.Altered level ofconsciousness.CerebellumCoordination and control ofvoluntary movement.• Tremors.• Nystagmus (Involuntarymovement of the eye).• Ataxia, lack of coordination.Informationcopyrighted byauthors listed andmay not bephotocopied formass distribution.Brain Stem:Ne r ve p a t h w a y o f c e rebralhemispheres.Auditory and Visual reflex centers.Cranial Nerves:• CN III - Oculomotor (Related toeye movement), [motor].• CN IV - Trochlear (Superior obliquemuscle of the eye which rotates theeye down and out), [motor].• Weber’s: CN III palsy andptosis (drooping) ipsalateral(same side of body).• Pupils: Size: Midposition todilated. Reactivity: Sluggish tofixed.• LOC (Loss of consciousness):Varies • Movement: Abnormalextensor ( muscle that extendsa part).• Respiratory: Hyperventilating.• CN (Cranial Nerve) Deficits:CN III, CN IV.

34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgPonsRespiratory Center.Cranial Nerves:• CN V - Trigeminal (Skinof face, tongue, teeth;muscle of mastication),[motor and sensory].• CN VI - Abducens (Lateralrectus muscle of eye whichrotates eye outward),[motor].• CN VII - Facial (Muscles ofexpression), [motor andsensory].• CN VIII - Acoustic (Internala u d i t o r y p a s s a g e ) ,[sensory].• Pupils: Size: Pinpoint• LOC:Semi-coma“Akinetic Mute”“Locked In” Syndrome.• Movement:Abnormal extensor.Withdrawal.• Respiratory:Ap n e u s t i c ( Ab n o r m a lrespiration marked bysustained inhalation).• Hyperventilation.• CN Deficits: CN VI, CNVII.Informationcopyrighted byauthors listed andmay not bephotocopied formass distribution.Medulla OblongataCrossing of motor tracts.Cardiac Center.Respiratory Center.Vasomotor (nerves havingmuscular control of the bloodvessel walls) Center Centers forcough, gag, swallow, and vomit.Cranial Nerves:• CN IX - Glossopharyneal( Mu s c l e s a n d m u c o u smembranes of pharynx, theconstricted openings from themouth and the oral pharynxand the posterior third oftongue.), [mixed].• CN X - Vagus (Pharynx,larynx, heart, lungs, stomach),[mixed].• CN XI – Accessory (Rotationof the head and shoulder),[motor].• Movement: Ipsilateral(same side) plegia (paralysis).• Pupils:Size: DilatedReactivity: Fixed.•LOC: Comatose.• Respiratory:Abnormal breathingpatterns.Ataxic.Clustered.Hiccups.• CN Palsies (Inability tocontrol movement):• Absent Cough.• Gag.• CN XII – Hypoglossal(Intrinsic muscles of thetongue), [motor].

About Brain Injury: Intracraniel PressureDoes the brain always swell? How do you know if the brain is swelling? Doesn’t the CT scanshow swelling? Is it possible that the person’s brain did not swell because of the use of the drugmanitol (protocol treatment in all ICU’s)? Is the chemical released if there is no swelling? If aperson didn’t need a shunt, can we assume there was no swelling?34 13th Ave NE, Suite B001Minneapolis, MN 55413612-378-2742800-669-6442Fax: 612-378-2789www.braininjurymn.orgE-mail: info@braininjurymn.orgPretty much all tissues in the body swell when traumatized. They also require more oxygen toheal. The brain is unique in that it rests inside a bone case, so when it swells, it experiencesmore trauma.The more damage the brain receives, the more it swells. This is caused by leakage from bloodvessels. When the brain swells, because it is housed inside the skull, it has no room to expand.This leads to a rise in pressure within the brain. This rise in pressure rapidly equals the arterialpressure thereby affecting the blood flow to the brain. This diffuse pressure which decreasesblood flow affects the ability of the cells within the brain to metabolize properly; the cells areunable to eliminate toxins which then accumulate.This phenomenon leads to a spiral effect which is what kills brain injured people who don’tget prompt attention. One of the big breakthroughs that lead to the survival rate we have nowfor brain injury today was learning to break this cycle. We are still very much in the stage oflearning to break this cycle. The most significant factor has been the use of monitoringdevices to inform treatments to prevent further damage.The brain requires both oxygen and glucose. In response to the trauma, changes occurin the brain which require monitoring to prevent further damage. The brain’s sizefrequently increases after a severe head injury. This is called brain swelling and occurswhen there is an increase in the amount of blood to the brain.Informationcopyrighted byauthors listed andmay not bephotocopied formass distribution.Water may collect in the brain which is called Brain Edema. Both Brain swelling and BrainEdema result in excessive pressure in the brain called Intracranial Pressure (ICP). Aroundthe-clockmonitoring during this time is essential in order that ICP can be immediatelytreated. Treatment of brain swelling can be difficult. Very strong medications are administered.Medications which help to draw fluid back out of the brain and into blood vessels may beuseful. Some medications help by decreasing the metabolic requirements of the brain. Othermedications increase blood flow into the brain which can help diminish the spiral effect causedby brain swelling.In some cases, removal of small amounts of fluids or from the brain or surgery may be beneficial.And in some cases, removal of damaged tissue may prevent further damage.