CH 28 - Head and Spinal Injuries

What is the nervous system?

A complex network of nerve cells that enables all parts of the body to function.

What 3 structures does the nervous system include?

Brain, spinal cord, and nerve fibers.

How is the nervous system protected?

The brain is protected by the skull, and the spinal cord is protected by the bony spinal canal; despite this, serious injuries can still damage the nervous system.

What are the two anatomic divisions of the nervous system?

Central nervous system (CNS) and peripheral nervous system (PNS).

What does the CNS include and what is the brain's role?

The brain and spinal cord; the brain controls the body and is the center of consciousness.

What are the 3 major areas of the brain?

Cerebrum, cerebellum, and brainstem.

Describe the cerebrum

The largest segment of the brain (~75% of its total volume); divided into right and left hemispheres; responsible for most voluntary motor function and conscious thought.

Describe the cerebellum

Coordinates balance and body movements.

Describe the brainstem

Controls most involuntary functions, including the cardiac and respiratory systems; the best-protected part of the CNS.

What makes up the spinal cord and how does it carry messages?

Mostly fibers extending from the brain's nerve cells; carries messages via the gray matter (neural cell bodies/synapses) and white matter (fiber pathways).

What are the meninges?

Three distinct membranes that further protect the brain and spinal cord (in addition to skin, muscle, bone, and other tissues).

Describe the dura mater

The outermost meningeal layer; a tough, fibrous layer resembling leather. Traumatic injury can cause bleeding between it and the inner surface of the skull.

Describe the arachnoid mater and subdural space

The arachnoid mater lies beneath the dura mater; the subdural space lies between the dura mater and arachnoid mater and contains bridging veins.

Describe the pia mater and subarachnoid space

The pia mater is the innermost meningeal layer, adhering to brain tissue; the subarachnoid space lies between the arachnoid and pia mater and contains cerebral blood vessels and CSF.

What is CSF and where is it produced?

Cerebrospinal fluid; produced within ventricular chambers inside the brain; bathes, nourishes, and cushions the brain and spinal cord.

How much CSF surrounds the CNS at any given time?

Approximately 125 to 150 mL.

What happens when an injury penetrates all protective layers of the CNS?

Clear, watery CSF may leak from the nose, ears, or an open skull fracture.

Describe the PNS's spinal nerves

31 pairs; conduct impulses from the skin/organs to the spinal cord, and motor impulses from the spinal cord to muscles.

Describe the PNS's cranial nerves

12 pairs; transmit information directly to/from the brain; perform special functions in the head/face (sight, smell, taste, hearing, facial movements).

What are the two major types of peripheral nerves?

Sensory nerves (carry information from the body to the brain via the spinal cord) and motor nerves (carry information from the CNS to the muscles).

What are connecting nerves and where are they found?

Found only in the brain and spinal cord; connect sensory and motor nerves with short fibers, allowing exchange of simple messages.

List the 3 types of activities the nervous system controls

Reflex activities, voluntary activities (consciously performed), and involuntary activities (not under conscious control).

What is a reflex arc?

When a sensory nerve in the spinal cord's connecting nerves detects an irritating stimulus, it bypasses the brain and sends the message directly to a motor nerve.

What handles voluntary vs. involuntary body functions?

The somatic (voluntary) nervous system handles voluntary activities; the autonomic (involuntary) nervous system handles functions without conscious effort.

What are the two divisions of the autonomic nervous system and their effects?

Sympathetic — fight-or-flight response (pupils dilate, lungs' smooth muscle dilates, heart rate increases, BP rises); parasympathetic — opposite effect (blood vessels dilate, heart rate slows, sphincters relax). They balance each other for homeostasis.

What makes up the skull?

The cranium (protects the brain) and the facial bones.

What is the foramen magnum?

The large opening at the base of the skull through which the brain connects to the spinal cord.

Name the 4 regions of the cranial vault

Occiput (most posterior), temporal regions (lateral, each side), parietal regions (between temporal and occiput), and frontal region (forehead).

Describe the spinal column

The body's central supporting structure; 33 vertebrae divided into 5 sections: cervical, thoracic, lumbar, sacral, and coccygeal.

How many vertebrae are in each spinal section?

Cervical: 7; Thoracic: 12; Lumbar: 5; Sacrum: 5 (fused); Coccyx: 4 (fused).

Describe vertebral anatomy

The front part of each vertebra is a round, solid block of bone called the vertebral body; the back part forms a bony arch. The arches form the spinal canal, which encases/protects the spinal cord.

How are vertebrae connected and cushioned?

Connected by ligaments and separated by cushions called intervertebral disks.

What can a head injury cause damage to?

Soft tissue, bony structures, or the brain; fatal injuries invariably involve the brain.

What are the two general types of head injuries?

Closed head injuries (brain injured, no opening into the brain) and open head injuries (an opening from the brain to the outside exists, often from penetrating trauma; brain tissue may be exposed).

What are the most common MOIs for head injuries?

Falls and motor vehicle crashes; also assaults, sports-related incidents, and child abuse.

What should you know about scalp lacerations?

Can be minor or serious; even small lacerations can cause significant blood loss (especially in children) and may contribute to hypovolemia in multi-injury patients.

List the signs of a skull fracture

Deformed appearance of the head, visible cracks in the skull, ecchymosis under the eyes (raccoon eyes), and ecchymosis behind one ear over the mastoid process (Battle sign).

Describe linear skull fractures

The most common type; radiographs are required to diagnose because there are often no physical signs such as deformity.

Describe depressed skull fractures

Result from high-energy direct trauma with a blunt object; frontal/parietal bones most susceptible; bony fragments may be driven into the brain, often with signs of neurologic injury.

Describe basilar skull fractures

Associated with high-energy trauma from diffuse impact; usually result from extension of a linear fracture to the base of the skull; diagnosed via CT; signs include CSF drainage from nose/ears, raccoon eyes, and Battle sign.

Describe open skull fractures

Often associated with trauma to multiple body systems; brain tissue may be exposed, greatly increasing infection risk; very high mortality rate.

Define traumatic brain injury (TBI)

Physical damage to the brain caused by an external force, potentially causing cognitive, movement, communication, behavioral, and emotional changes; may be mild (concussion) or moderate to severe.

What are the two broad categories of TBI?

Primary (direct) injury and secondary (indirect) injury.

Describe primary vs. secondary brain injury

Primary brain injury results instantaneously from impact; secondary brain injury increases the severity of the primary injury and may develop minutes to days later.

List causes of secondary brain injury

Cerebral edema, intracranial hemorrhage, increased intracranial pressure, cerebral ischemia, infection. Hypoxia and hypotension are the two most common causes.

Describe coup-contrecoup injury

Initial impact injures the front of the brain with stretching/tearing of the posterior portion; the head falling back against the headrest then injures the rear part of the brain.

When might cerebral edema develop after a head injury?

May not develop until several hours after the initial injury; low blood oxygen levels aggravate it.

What can lead to increased intracranial pressure (ICP)?

Accumulation of blood within the skull or swelling of the brain.

What happens if enough ICP is applied to the brainstem?

It may herniate (protrude) through the foramen magnum, producing abnormal vital sign changes.

List signs of increased ICP

Abnormal respiratory patterns (ataxic/Biot, Cheyne-Stokes, central neurogenic hyperventilation); headache, nausea, vomiting, decreased alertness, sluggish pupils, decerebrate/decorticate posturing, increased/widened pulse pressure.

Define the Cushing reflex

The symptom triad of increased systolic blood pressure, decreased heart rate, and irregular respirations.

Describe an epidural hematoma

Accumulation of blood between the skull and dura mater; nearly always from a blow producing a linear fracture of the thin temporal bone (tearing the middle meningeal artery); arterial bleeding causes rapidly progressing symptoms.

What is the classic presentation of an epidural hematoma?

Immediate loss of consciousness, followed by a brief lucid interval, then lapse back into unconsciousness; the pupil on the side of the hematoma becomes fixed and dilated. Mortality ~20% without early surgery.

Describe a subdural hematoma

Accumulation of blood between the dura mater and arachnoid mater; usually from falls or strong deceleration forces; more common than epidural hematoma; venous bleeding causes signs to develop more gradually.

Why are older adults at greater risk for subdural hematoma?

The subdural space is enlarged, allowing the brain to move more freely and bridging veins to stretch/tear more easily; more bleeding can occur before symptoms appear; often compounded by anticoagulant medication use.

What symptoms are typical of subdural hematoma?

Fluctuating level of consciousness or slurred speech; any suspected subdural hematoma needs hospital evaluation.

Describe a subarachnoid hemorrhage

Bleeding into the subarachnoid space where CSF circulates; common causes are trauma or ruptured aneurysm; patient reports a sudden, severe headache, plus possible nausea, vomiting, dizziness, light sensitivity, neck rigidity/pain.

What is the prognosis for a sudden, severe subarachnoid hemorrhage?

Usually results in death; survivors often have permanent neurologic impairment.

Describe an intracerebral hematoma

Bleeding within the brain tissue itself; can occur after penetrating trauma; high mortality rate even with surgical evacuation; condition often deteriorates quickly once symptoms appear.

Define concussion

A mild TBI with temporary loss or alteration of brain function without demonstrable physical damage; a functional, not structural, change.

What percentage of concussion patients lose consciousness?

About 90% do NOT experience loss of consciousness.

Define retrograde amnesia

The ability to remember everything except the events leading up to the injury.

Define anterograde amnesia

The inability to remember events after the injury (also called posttraumatic amnesia).

List additional signs/symptoms to ask about after a concussion

Dizziness, weakness, visual changes, changes in mood, nausea/vomiting, ringing in the ears, slurred speech, inability to focus.

How should suspected concussion patients be treated in the field?

Assume a more serious injury exists until proven otherwise by CT scan or physician evaluation.

Define brain contusion

Bruising of the brain tissue from blunt trauma; far more serious than a concussion, as it involves physical injury to brain tissue and may cause long-lasting/permanent damage.

What other conditions can cause brain injury besides trauma?

Medical conditions such as blood clots or hemorrhages, high blood pressure, or blood vessel problems causing spontaneous bleeding into the brain; signs/symptoms mirror TBI.

Define axial loading injury

Force applied along the vertical/longitudinal axis of the spine, transmitting load along the entire vertebral column; can cause disk herniation, spinal cord/nerve root compression, and vertebral fragmentation into the spinal canal.

List other forces that can cause spinal injury

Hyperflexion, hyperextension, hyper-rotation, excessive lateral bending (e.g., side-impact collision), and distraction (pulling apart of vertebrae, e.g., hanging).

What signs/symptoms suggest spinal injury?

Pain and tenderness on palpation; possibly a palpable/observed 'step-off' (displaced vertebra); numbness, tingling, or paralysis below the injury level. Note: a severe spinal fracture may show no signs at all.

What should you do if you suspect a spinal injury?

Spinal motion restriction (SMR) is indicated.

List MOIs that should raise suspicion for head/spinal injury

Motor vehicle collisions (incl. motorcycles, snowmobiles, ATVs); pedestrian–MV collisions; falls >10 feet; blunt trauma to head/neck; penetrating trauma to head/neck/back/torso; rapid deceleration injuries; hangings; axial loading injuries; diving accidents.

What are scene size-up priorities for head/spine trauma?

Scene safety (evaluate hazards, use standard precautions, call for ALS early) and mechanism of injury/nature of illness (look for indicators of MOI and consider how it produced expected injuries).

What is the focus of the primary assessment in head/spine trauma?

Identifying and managing life-threatening concerns; threats to circulation, airway, or breathing must be treated immediately, following the XABC sequence if life-threatening external hemorrhage exists.

List factors indicating the need for SMR following blunt trauma

GCS <15 or evidence of intoxication; midline neck/back pain or tenderness; numbness/motor weakness in one body area; visible/palpable spinal deformity; other distracting injuries; circumstances interfering with reliable exam (e.g., communication barriers, emotional distress).

What suggests a head injury in a responsive patient?

Confused or slurred speech, repetitive questioning, or amnesia; in trauma, assume the cause is TBI until proven otherwise.

When should you suspect spinal injury even without confirmation?

In unresponsive trauma victims or those with a decreased AVPU level — spinal injury cannot be reliably ruled out.

How should you open the airway if spinal injury is suspected?

Manually hold the head still and use a jaw-thrust maneuver; if ineffective, the head tilt-chin lift is acceptable.

What should you do if a head-injured patient vomits and suction is inadequate?

Roll the patient while keeping the spine as straight as possible to minimize secondary spinal injury.

What breathing patterns can result from increased brain pressure?

Cheyne-Stokes respirations, Biot respirations, or even apnea.

What oxygenation targets apply to suspected severe TBI patients?

Pulse oximeter should not fall below 90%, ideally 95–99%; a single episode of hypoxia nearly doubles the risk of death or permanent disability.

What ETCO2 range should be maintained in head injury patients, and why avoid hyperventilation?

35–45 mm Hg; routine hyperventilation is discouraged because rapid ventilatory rates constrict cerebral blood vessels, reducing blood flow and worsening hypoxic injury. Mild hyperventilation is acceptable only if imminent brainstem herniation is suspected.

What do pulse rate abnormalities suggest in head injury patients?

A pulse too slow can indicate a serious condition; a rapid pulse may indicate shock. A single episode of hypoperfusion can cause significant brain damage or death.

What transport considerations apply to head trauma patients?

May need rapid extrication if airway impaired, open head wounds, abnormal vitals, or no response to painful stimuli; ensure patent airway and high-flow O2; have suction ready; may need aeromedical transport; elevate head 30° if supine (to reduce ICP); maintain SMR.

What questions should you ask to determine the chief complaint in head/spine trauma?

What happened? Where does it hurt? Does your neck or back hurt? Can you move your hands and feet? Did you hit your head? Did you lose consciousness?

Does the ability to walk, move extremities, or feel sensation rule out spinal cord injury?

No — it does not necessarily rule out a spinal cord injury.

What should you instruct a patient with suspected spinal injury to do?

Keep still and not move the head or neck.

What monitoring targets apply during secondary assessment of head/spine trauma?

Maintain ETCO2 between 35–40 mm Hg and pulse oximetry above 90%.

What physical exam method should be used, and what should be checked before moving the patient?

DCAP-BTLS to examine the entire body; check perfusion, motor function, and sensation in all extremities before moving the patient.

What is the most reliable sign of a head injury?

A decreased or altered level of consciousness.

What should you avoid doing with open scalp lacerations or impaled objects?

Do not probe open scalp lacerations with a gloved finger (may push bone fragments into the brain); do not remove an impaled object from an open head injury.

What scale is used for a baseline neurologic exam, and what is it used for elsewhere?

The Glasgow Coma Scale (GCS); if your jurisdiction uses the Revised Trauma Score (RTS), GCS findings help determine RTS value.

What should the spine examination check for?

Overt signs of injury/deformity; circulation, motor, or sensory problems in the extremities (noting level of impairment); pain/tenderness on palpation; numbness, weakness, tingling; soft-tissue injuries in the spinal region.

What may severe spinal injury cause besides sensory/motor loss?

Loss of sensation or paralysis below the injury level, incontinence, priapism (prolonged erection), and diminished ability to maintain body temperature.

What nerve can be damaged by cervical spine injury, and what's the consequence?

The phrenic nerve, which innervates the diaphragm; these patients need urgent ventilatory assistance.

How often should a head/spine trauma patient be reassessed?

At least every 5 minutes — repeat the primary assessment, reassess vital signs/chief complaint, and recheck interventions.

What may be the earliest indication of a problem during reassessment?

Alterations in the patient's mental status, indicating possible rapid deterioration of neurologic function.

How should a CSF leak be managed?

Cover the wound with sterile gauze to prevent further contamination, but do not bandage it tightly.

How often should vital signs be documented for seriously injured vs. more stable patients?

Seriously injured: every 5 minutes. More stable: every 15 minutes.

What are the 3 general principles of head injury care?

Control bleeding and provide adequate circulation to maintain cerebral perfusion; establish an adequate airway; assess and continuously monitor the patient's baseline level of consciousness.