Head and Spinal Cord Trauma May 2011 CE Condell Medical Center EMS System Site Code #107200E-1211 Objectives by: Mike Higgins, FF/PM Grayslake Fire Department Packet by: Sharon Hopkins, RN, BSN, EMT-P 1 Objectives Upon successful completion of this module, the EMS provider will be able to: 1. List risky behaviors contributing to brain and spinal cord injuries. 2. Describe typical injury patterns related to specific mechanisms of injury. 3. Describe the anatomy of the brain. 4. List contents of the skull. 5. Describe the mechanisms for the development of secondary brain injury. 6. Describe the pathophysiology of traumatic brain injuries including pressures related to brain blood flow. 7. Explain the normal anatomy and physiology of 2 the spinal column and spinal cord. Objectives cont’d 8. Describe the pathophysiology of traumatic spinal cord injuries. 9. Describe components of a neurological assessment in the field. 10. List signs and symptoms of spinal cord injuries. 11. Describe the pathophysiology of neurogenic shock. 12. Describe prehospital treatment based on Region X SOP’s of the patient with a head or spinal cord injury. 13. Review ventilation rates of the stable and unstable patients with head and/or spinal cord 3 injuries. Objectives cont’d 14. Review the Region X Infield Spinal Clearance SOP. 15. Review measurement of fitting a cervical collar. 16. Review the procedure for demonstrating the standing backboard takedown procedure. 17. Demonstrate the proper measurement and placement of a cervical collar. 18. Demonstrate the standing take down with the back board. 19. Actively participate in case scenario discussion. 20. Successfully complete the post quiz with a score of 80% or better. 4 What’s The Big Deal? Traumatic brain injury (TBI) – Major cause of death and disability in multiple trauma patients – Severe injury indicated with GCS <9 5 TBI Statistics Many patients will be minors, therefore, you will also be dealing with parents and caregivers 6 Traumatic Brain Injury (TBI) 40% of trauma patients have CNS injury Death rate twice as high (35%) as patient without CNS injury Account for 25% of all trauma deaths Account for up to 50% of all MVC deaths Cost worldwide is huge – Lives lost – Families destroyed – Money spent for care CNS – central nervous system 7 Risky Activities Resulting in Spinal Cord Injuries MVC – 44.5% - major cause – SUV’s & jeeps prone to flipping Falls 18.1% – Most common in persons >45 years of age Violence 16.6% – More common in urban settings Sports 12.7% – Diving most common contributing sport Other medical causes make up <10% 8 Typical Head/Neck Injury Patterns T-bone – lateral impact – Coup/contrecoup head injuries – Neck strain up to fractures – Most injuries from collision with inside of vehicle Rear impact – Hyperextension of neck esp if head rest not fitted – Lumbar spine injury if seat breaks Rollover – Body impacted in all directions so injury potential high – Increased chance for axial loading on spine – Often lethal injuries when ejected 9 Typical Head/Neck Injury Patterns ATV – Injuries depend on MOI and part of body impacted – High index of suspicions for head and spinal injuries Falls from height – Evaluate distance, body area impacted, type of surface struck – Landing on feet, check for axial loading to lumbar and cervical spine areas 10 Anatomy of the Skull Scalp highly vascular Skull is rigid bone – Serves as protection Dura mater – Tough fibrous covering of brain Arachnoid mater – Lies under dura – Arteries & veins suspended from this Pia mater – On surface of brain 11 Anatomy of the Brain Each lobe has a unique function Identified disabilities can help pinpoint area of insult or injury – Proper assessment can point to area of injury – Always reassess watching for trends 12 Anatomy of the Brain Cerebrum – Frontal lobe Personality Judgment – Temporal lobe Hearing Memory – Parietal lobe Language formation; processing senses – Occipital lobe Vision 13 Anatomy cont’d Cerebellum – Control of movement, balance, coordination Brainstem – arousal & consciousness center; involved in basic life functions breathing, reflexes – Pons – motor & sensory relay center – Medulla- controls autonomic functions (breathing, digestion, heart & blood vessel function 14 Contents of the Skull There is no extra space If one component increases, usually brain tissue swelling, it is usually at sacrifice of one of the other components –Brain – 80% –Blood volume – 10% (150 ml) –CSF – 10% (150 ml ) 15 CSF – cerebral spinal fluid Brain Function Brain VERY sensitive to levels of oxygen and glucose – Brain has a high metabolic rate both at rest or engaged in activity – Brain is 2% of total body weight – Receives 15% of cardiac output – Consumes 20% of body’s oxygen – Relies on aerobic metabolism – Needs constant availability of glucose, thiamine (to metabolize glucose), and oxygen 16 Comparative Blood Flow in ml/minute Organ At rest During strenuous activity Heart 250 750 Skin 400 1900 Other 600 400 Brain 750 Steady at 750 Skeletal muscle 1000 12,500 Kidneys 1200 600 Viscera 1400 600 Total 5600 17,500 17 Adding Insult to Injury Coup-contrecoup injuries – Brain shifts/floats inside skull Base of skull rough – causes more injury – Injuries at point of impact and away from point of impact Ex: forehead injury can result in additional injury to occipital area 18 Secondary Injury Primary injury occurs at time of insult Secondary injury occurs later as a result of what happens initially Initial swelling causes decreased perfusion Secondary complications stem from hypoxia and decreased perfusion 19 What is your major focus? Management of injury focused on – Proper care Identification of injuries –An accurate general impression leads to appropriate care Appropriate interventions initiated – Rapid transport to secondary care Do things right to prevent contributing to secondary injuries 20 Common Problems Related To TBI Airway compromise Inadequate ventilation Hypotension – An independent risk factor contributing to mortality Focus on these critical aspects and perform appropriate interventions as needed 21 Pressures Related to Blood flow ICP is pressure of brain and contents within skull CPP - cerebral perfusion pressure –Pressure of blood flowing thru brain; pressure necessary to perfuse brain (CPP=MAP-ICP) MAP - mean arterial pressure –Average pressure within an artery; pressure maintained in vascular system 22 Reflexive Response to ICP Cushing’s reflex – Protective response to preserve blood flow to the brain B/P will increase Systolic B/P increasing as diastolic B/P stays same or increases Widening pulse pressure Heart rate will decrease Effort to lower elevating blood pressure Respirations may be irregular Note vital signs move opposite to shock 23 Cerebral Perfusion Brain requires unique range to function Increased ICP causes brain herniation Hypotension not tolerated with ICP Examples of problems*: – MAP constant + ICP = CPP – MAP decreases + ICP steady = CPP – MAP decreases + ICP = CPP critical Any negative change in B/P or ICP affects blood flow in brain *Normal values of MAP, ICP, and CPP listed in Notes section 24 Signs and Symptoms Head Injury Use inspection/observational skills with mechanism of injury to increase suspicion of head and neck injuries 25 Brain Injuries - Concussion Prevalent in athletic activities No structural injury to brain Often brief loss of consciousness or, at minimum, confusion, then return to normal Possible amnesia (short-term retrograde) Short term memory loss – will ask repetitive questions Dizziness, headache, ringing in ears, nausea 26 Brain Injuries – Cerebral Contusion Bruised brain tissue History prolonged unconsciousness or serious altered level of consciousness (confusion, amnesia, abnormal behavior) Focal neurological signs – Related to a specific area of the brain – Weakness, speech problems, personality or behavioral changes 27 Brain Injuries – Subarachnoid Hemorrhage Blood in subarachnoid space – Traumatic injury or spontaneous Blood causes irritation Severe headache – “Worst headache of my life” Coma Vomiting 28 Brain Injuries – Diffuse Axonal Injury Most common type of injury from blunt head trauma Generalized, diffuse edema Unconscious No focal deficits – Swelling, edema, injury too widespread so no specific isolated sign/symptom pointing to 1 area of the brain 29 Brain Injuries – Acute Epidural Hematoma Bleeding between dura and skull Often from tear in middle meningeal artery from skull fracture in temporal area – Runs along inside of skull in temporal area – Arterial bleed so onset usually rapid for signs/symptoms Initial loss of consciousness and now lucid Signs ICP after few hours – Vomiting, headache, altered mental status – Motor deficit opposite side to injury (contralateral) 30 – Dilated, fixed pupil on side of injury (ipsilateral) Brain Injuries – Acute Subdural Hematoma Bleeding between dura and arachnoid Bleeding is venous Slow onset to ICP (hours, days) Headache, changing level of consciousness, focal neurological signs – Weakness one sided, slurred speech Poor prognosis due to associated brain tissue injury High risk: elderly, anticoagulant use, chronic alcoholics 31 Brain Injuries – Intracerebral Hemorrhage Bleeding within brain tissue Blunt or penetrating injuries Surgery not often helpful Signs and symptoms depend on region of brain injured Patterns similar to a patient with a stroke Altered level of consciousness common If awake, complain of headache & vomiting 32 Spinal Column Spinal column is the bony tube of 33 vertebrae separated by discs that act as shock absorbers Alignment maintained by strong ligaments and muscles Supports body in upright position Allows use of extremities Protects delicate spinal cord 33 Spinal Cord Electrical conduit Extension of brain stem Continues down to first lumbar vertebrae then separates into nerves Surrounded and bathed by cerebrospinal fluid Cerebrospinal fluid and flexibility provide some protection 34 Spinal Column/Cord 35 Spinal Cord cont’d Nerve roots exit at each vertebral level – Nerve roots carry signals from brain to specific sites – Nerve roots carry sensory signals from body to spinal cord to brain – Susceptible to traumatic injury 36 Spinal Cord cont’d Integrates/brings together the autonomic nervous system –2 components: parasympathetic and sympathetic nervous system –Assists in controlling Heart rate Blood vessel tone Blood flow to skin 37 Mechanisms of Injury Penetrating injuries – Secure the object in position found – Do no further harm! 38 Mechanisms of Blunt Spinal Injury Hyperextension – Excessive posterior movement of head or neck Face into windshield Elderly person falling to floor, striking chin Football tackler Dive into shallow water Hyperflexion – Excessive anterior movement of head onto chest Rider thrown from horse or motorcycle Dive into shallow water 39 Mechanisms cont’d Compression – Weight of head or pelvis driven into stationary neck or torso Dive into shallow water Fall onto head or legs >10-20 feet Rotation – Excessive rotation of torso or head & neck; moves one side of spinal column against other side Rollover MVC Motorcycle crash 40 Mechanism cont’d Lateral stress – Direct lateral force on spinal column; typical shearing one level of cord from another T-bone MVC Distraction – Excessive stretching of column and cord Hanging Child inappropriately wearing shoulder belt around neck “Clothes lining” with snowmobile or motorcycle riders and passengers 41 Disk Problems A preexisting problem can be aggravated at time of injury 42 Spinal Cord Injuries Complete injury – No function, sensation, voluntary movement below level of injury – Both sides affected equally Incomplete injury – Some function preserved below level of injury – May move 1 limb more than other – May have more function on 1 side of body than other – May have sensation but no movement 43 Spinal Cord Injuries Tetraplegia (also referred to as quadriplegia) – Injury in cervical area – Loss of muscle strength in all 4 extremities Paraplegia – Injury in spinal cord in thoracic, lumbar or sacral segments – Level of impairment dependent on level of injury 44 Spinal Cord Injury Patterns Cervical area injury = quadriplegic C1-C2 – may lose involuntary function of breathing – Watch for excessive use of abdominal muscles to breath C4 and above – often require use of ventilator for breathing C5 – shoulder/bicep control but no control of hand or wrist C6 – wrist control but no hand function 45 Spinal Cord Injury Patterns C7-T1 – can straighten arms, dexterity problem with fingers and hands Thoracic level and below = paraplegic T1-T8 – has control of hands, poor trunk control due to lack of abdominal muscle control T9-T12 – good trunk & abdominal muscle control; sitting balance good. Decreased control hip flexor and legs 46 Spinal Cord Injury Consequences Often experience: – Bowel and bladder dysfunction – Male fertility often affected – Inability to regulate B/P; hypotension usual – Inability to sweat below level of injury – Decrease control to regulate body temperature – Chronic pain 47 Dermatomes Mapping of body Easier to identify injured areas by isolating location of complaints as related to zones of altered sensation 48 Neurogenic Shock Occurs when brain signals interrupted for autonomic functions Ability to vasoconstrict limited – No sympathetic tone, vessels dilate Relative hypovolemia – preload ventricular filling Frank Starling reflex contraction strength cardiac output – No hormone release to heart rate 49 Neurogenic Shock Signs and symptoms –Bradycardia –Hypotension –Cool, moist, pale skin above cord injury –Warm, dry, flushed skin below cord injury 50 Neurological Assessment Serial vital signs – watch for: – ICP: B/P; pulse rate – Neurogenic shock B/P; pulse; skin warm and dry below level of injury Serial AVPU Serial GCS Pupillary response Response to motor and sensory – Included in CMS, SMV, PMS assessment Babinski reflex present – big toe extends up when sole stroked from heel to toe 51 Signs and Symptoms Spinal Cord Injury (ie: “Clues”) Pain on movement of back or spinal cord Deformity Guarding against movement Loss of sensation Inability to move Weak or flaccid muscles Abnormal positioning Loss of control of bladder or bowels Priapism – erection of penis Neurogenic shock 52 Focus of Field Treatment Provide adequate airway Monitor for effective oxygenation and ventilation Maintain CPP (cerebral perfusion pressure) – Can’t measure easily in field – So watch systolic blood pressure Something EMS can monitor in the field Assume low B/P due to hypovolemia until proven otherwise 53 Region X SOP Routine trauma care – Scene size-up Determining mechanism of injury could be good tip-off to suspected injuries – Initial/primary survey Identify and treat life threats – Identify transport priority – Perform rapid trauma survey if critical or life threats found – Focused exam on minor injuries 54 Region X SOP Head/Spinal Injuries Routine trauma care Obtain GCS – GCS<9 indicates severe brain injury IV fluid challenge (200 ml increments) if B/P <90mmHg If altered LOC obtain blood glucose – If <60 treat with Dextrose Assess oxygenation – Maintain SpO2 >94% 55 Ventilation Rates Stable Head/Spinal Injuries Relatively stable patient needing BVM assistance with 100% O2 Adult 10 breaths/min 1 breath every 6 seconds Child 20 breaths/min 1 breath every 3 seconds Infant 25 breaths/min 1 breath every 2.5 seconds 56 Ventilation Rates Unstable Head/Spinal Injuries Rapid neurological deterioration – Unequal pupils, posturing, lateralizing signs Signs indicating a deficit related to one of the hemispheres – Example: speech problem, hemiparesis, abnormal reflexes, facial asymmetry, abnormal eye movement – Ventilate with BVM and 100% O2 Adult 20 breaths/minute (1 every 3 seconds) Child 30 breaths/minute (1 every 2 seconds) 57 Infant 35 breaths/min (1 every 1.7 seconds) Hazards of Hyperventilation Hyper/hypoventilation refers to level of CO2 maintained in body Capnography is the ideal measurement tool for exhaled CO2 levels Levels of CO2 influence vessel size – RR CO2 retained vasodilation – RR CO2 retained vasoconstriction – Either way, the brain does not get perfused Hypoxia develops – Hypoxia anaerobic metabolism acidosis 58 Unhealthy Environment Hypo and hyperventilation both with adverse consequences for the patient Development of hypoxia and acidosis – Hypoxia is NOT tolerated in the brain Cells do not function well in this environment Interventions not effective in this environment 59 Trauma Patient Assume any injury from the clavicles on up includes a head and/or spinal cord injury – Cannot clear the c-spine – Perform spinal motion restriction Also referred to as c-spine control Avoid use of word “traction” as you are not pulling on the head and neck 60 In-field Spinal Clearance Evaluate – Mechanism of injury – Signs and symptoms – Patient reliability When in doubt, fully immobilize Document assessment and findings to support application of motion restriction/immobilization devices or when not using equipment 61 Cervical Collar Measurement Why do we keep talking about how to measure for placing a cervical collar? – We still see a high number of patients transported to the ED with cervical collars in the no-neck position 62 IF THE MAJORITY OF YOUR PATIENTS ARE WEARING A NONECK SIZED COLLAR, THEN YOU ARE NOT PROPERLY MEASURING THEM! 63 Measuring for Cervical Collar Measure eyeing horizontal line from bottom of chin to top of shoulder Measure on collar plastic from bottom up to closest hole opening Collar should rest on clavicles & support the jaw 64 Standing Backboard A Team Effort Approach 65 Standing Backboard Purpose –To place the ambulatory patient into a supine position without compromising the spine To rapidly move the patient into the supine position will need 3 persons, a cervical collar, and a long backboard –Strapping can be (and most often is best) applied once the patient is supine 66 Standing Backboard Position tallest crew member behind patient –Manual stabilization/motion restriction of c-spine taken 2nd EMT measures and applies cervical collar while manual control maintained 2 EMT’s position backboard between patient and person maintaining manual stabilization/motion restriction of head and neck 67 Standing Backboard 2nd and 3rd EMT’s reach hand nearest to patient under the patient’s armpit and grasps the backboard Patient will be temporarily suspended by the armpits as the backboard is lowered As the signal is given, the backboard is slowly lowered 68 Standing Backboard Person with manual stabilization walks backward to keep up with the lowering pitch of the backboard Remember – Heaviest weight of head is in occipital area Have fingers/hands spread in good position to support the head before changing the patient’s positioning 69 Backboard slowly lowered using multiple personnel and keeping head and neck immobilized 70 Standing Backboard As the board is lowered, all 3 persons work very closely together Once the backboard is lowered, the patient may need to be adjusted onto the backboard Complete spinal immobilization/motion restriction process by securing the patient to the backboard Rescuers need to watch their own body mechanics to prevent injury 71 Case Scenarios Divide into smaller groups Read the presentation Form a general impression Discuss treatment options Discuss what/how/when to reassess the patient Decide what treatment to continue or what adjustments need to be made Present to the group and give explanation to defend your decisions 72 Case Scenario # 1 17 y/o patient injured at bike track – Fell head first off bike Conscious, confused VS: 92/50; 60; 14 Repeat: 84/46; 54; 14 Arms not moving Legs move c/o pain to neck Warm & dry 73 Case Scenario # 1 No allergies; no medications No medical history Last ate 2 hours ago Doesn’t remember how he wiped out Reported to lose control speeding around track Upon arrival, bystanders holding c-spine No movement detected in upper extremities; lower ext move spontaneously If “belly” breathing noted, what does it mean? – Excessive use of abdominal muscles – Watch for respiratory arrest 74 Case Scenario #1 Treatment/interventions – C-spine control - Spinal motion restriction – IV – O2 – monitor (what should be enroute?) – Fluids – Prepare to support ventilations – Obtain blood glucose level 75 Case Scenario #1 Patient had spinal cord injury – Central cord syndrome most common with hyperextension – Weakness/impairment in arms & hands – Legs are spared – Variable loss of sensation Exhibiting neurogenic shock – B/P; bradycardia – Tank expanded with vasodilation – needs IV fluids 76 Case Scenario #1 Belly breathing indicates cervical injury until proven otherwise Chest muscles and diaphragm not being used for ventilation Abdominal muscles back up to ventilate – Not use to this function – Will tire/fatigue – Patient may respiratory arrest 77 Case Scenario # 2 41 y/o male restrained driver T-boned by SUV Unconscious, shallow respirations Vital signs: 146/82, 94, 32, SpO2 94% Blood draining from left ear and left nares Diminished breath sounds on left Deformed left arm, left femur 78 Case Scenario # 2 GCS: – Eye opening – none – Verbal response – moans – Motor – Withdrawing on left, no movement on right Repeat VS: 168/72, 44, 16 Pupils: fixed/dilated left, right minimally reactive What would raccoon eyes or Battle’s signs indicate? 79 Case Scenario #2 Treatment/interventions – C-spine control - Spinal motion restriction – IV – O2 – monitor (what should be enroute?) – BVM support at 20/minute (1 every 3 seconds) (patient unstable) – Rapid transport to highest trauma level within 25 minutes – Obtain blood glucose level 80 Case Scenario #2 Patient injuries – Fractured skull Raccoon eyes indicate anterior basilar skull fx – Epidural bleed – Fractured left clavicle – Fractured ribs with hemothorax – Fractured left humerous – Fractured pelvis – Fractured left femur 81 Case Scenario # 3 60 y/o female riding her bike Hit pothole and fell off bike Helmet damaged Short loss of consciousness; asking repetitive questions; nauseated; complains of headache and blurred vision Vital signs: 132/78, P-98, R-20, SpO2 99% 82 Case Scenario # 3 GCS: eye opening spontaneous – Verbal – slightly confused – Motor – obeys commands Pupils: PERL 83 Case Scenario #3 Treatment/interventions – C-spine control – spinal motion restriction Patient not reliable – IV–O2–monitor (what should be enroute?) – Watch for nausea and vomiting to protect airway – Trend vital signs and level of consciousness – Check blood sugar level Patient has altered level of consciousness 84 Case Scenario # 3 GCS – 4-4-6; Total 14 Patient had a concussion Admitted overnight for observation Continued to have a mild headache Other complaints resolved Discharged home next day 85 Case Scenario # 4 5 y/o is vomiting, has headache, was acting “bizarre” Now has an altered level of consciousness Hx of falling off jungle gym earlier today Initial loss of consciousness for few minutes then lucid; alert & oriented B/P 90/46, 104, 24 Nauseated 86 Case Scenario # 4 GCS: – Eye opening – after calling their name – Verbal response – talking nonsense – Motor response – pulling at equipment with right hand, trying to get your hands off him Pupils - right slower to react, midsize Left extremities flaccid Bruise and swelling noted over right forehead above ear Minor scratches to bilateral arms 87 Case Scenario #4 Treatment/interventions –C-spine control – spinal motion restriction –IV – O2 – monitor (what should be enroute?) –Anticipate rapid deterioration and prepare to secure airway 88 Case Scenario # 4 GCS – 3-3-5; Total 11 Patient had right epidural hematoma Confirmed on CT Emergently taken to OR Hematoma evacuated Signs and symptoms slowly resolving Patient discharged home with outpatient physical and occupational therapy 89 Case Scenario # 5 Patient presents to ED with FB stuck in head Awake, talking, following commands How do you immobilize this object? 90 Case Scenario #5 Immobilize in position found Constantly monitor level of consciousness Possibly need to shorten a FB to facilitate transfer in the ambulance Not knowing where tip of FB is, assume head and neck injuries and treat for both 91 Case Scenario #5 Patient taken to OR Arrow successfully removed with part of skull Plate placed in OR Post-op patient had altered sense of taste and had difficulty perceiving tactile sensations 92 Case Scenario # 6 45 y/o male passenger MVC involving a deer Patient unconscious Facial trauma evident Gurgling respirations Radial and carotid pulses noted regular and normal 93 Case Scenario # 6 Vital signs: 92/62, P-74, R-18 Pupils: right reactive, left non-reactive GCS: – Eyes – eyelids move when body touched – Verbal – silent – Motor – flexes right arm to pain, left arm straightens to pain Repeat VS: 88/50, P-62, R-28 irregular 94 Case Scenario #6 Treatment/interventions – C-spine control – spinal motion restriction – Open and secure airway Modified jaw thrust – Support ventilations 20 breaths per minute – IV-O2-monitor (what should be enroute?) – Rapid transport once extricated – Is there a need for helicopter service in your town/your location? 95 Case Scenario # 6 GCS – 2-1-3; Total 6 Pt had intracerebral hematoma and bilateral pneumo/hemothorax Chest tube placed in ED for chest injuries Remains on ventilator in ICCU Unable to do brain surgery due to location of bleed 96 New Recommendations of the AAN American Academy of Neurology states 1. Any athlete who is suspected to have suffered a concussion • Remove from participation until evaluated by a physician with training in the evaluation and management of sports concussions 2. No athlete should be allowed to participate in sports if he or she is still experiencing symptoms from a concussion 97 AAN Recommendations cont’d 3. Following a concussion, a neurologist or physician with proper training should be consulted prior to clearing the athlete for return to participation 4. A certified athletic trainer should be present at all sporting events, including practices, where athletes are at risk for concussion 5. Education efforts should be maximized to improve the understanding of concussion by all athletes, parents, and coaches 98 TBI Prevention is the most effective treatment –Use of restraints in vehicles Shoulder/lap Car seats –Use of helmets –Following guidelines when players can return to play following concussion 99 Hands-on Practice All participants to measure a peer for cervical collar placement Practice in groups of 3 standing backboard take-down –Have 4th person role play a patient 100 Bibliography Bledsoe, B., Porter, R., Cherry, R. Paramedic Care Principles & Practices Third Edition. Brady. 2009. Campbell, J.E. International Trauma Life Support for Prehospital Care Providers, 6th Edition. Brady. 2008. Region X SOP March 2007; amended January 1, 2008 101 Internet Reference Sites http://www.answers.com/topic/intracranialpressure http://www.bmj.com/content/338/bmj.b1683.full http://faculty.washington.edu/chudler/facts.html www.link-intl.com/gulfspine/Anatomy.html http://neuropathology.neoucom.edu/chapter14/c hapter14CSF.html http://www.spinal-cord.org/at-risk-activities.htm http://www.spinalinjury.net/html/_spinal_cord_1 01.html 102