Spinal Cord Injury Flashcards
What is a spinal cord injury?
SCI is damage to the spinal cord that results in a loss of function
Tetraplegia/Quadriplegia
injury to the spinal cord between the spinal cord segments C1 and T1
this causes paralysis and loss of feeling involving 4 limbs as well as the bladder, bowel and sexual organs
Paraplegia
injury to the spinal cord below the neck
below T1 cord segment
causes weakness and loss of feeling in the trunk, legs and bladder, bowel and sex organs
arms and hands are normal
Percentages of spinal cord injury
46% Land transport crashes
32% High or Low fall
Function of the vertebral column
- support and carry the weight and trunk and limbs
- provide movement and flexibility
- protect and encase the spinal cord
- provide attachment for other structures
where are the 33 Vertebrae located
7 cervical 12 thoracic 5 lumbar 5 sacral (fused) 4 coccygeal (fused)
what are the four curvatures
cervical - concave
thoracic - convex
lumbar - concave
sacral - convex
C1 and C2
C1 - atlas
C2 - axis
allow for us to rotate our head, look up, to the side, look down, mobility
delicate and susceptible to injury if placed under force
Which is the longest part of the vertebrae
thoracic
Which part of the vertebrae articulates with and attaches to the ribs
thoracic
lumbar
lower back
receives the most stress and is the weight bearing component of the spine
caudia equina
tail of nerves exiting through the sacrum/ base of vertebral column
what matter protects the spinal cord
dura mater
arachnoid matter
epidural space
made up of fat, contains blood vessels that supply the cord and other structures
dorsal root
within the dorsal root there is a spinal ganglion where motor neurons communicate
blood supply of spinal cord
anterior spinal artery and its branches supply the antero-lateral half of the spinal cord
paired posterior spinal arteries and branches supply the postero-lateral half of the spinal cord
spinothalamic tract
simple touch,, pain and temperature on opposite side of body
dorsal (posterior) columns
sensations from same side of body
what are the 3 main ascending (afferent) pathways
non-specific ascending pathway
specific ascending pathway
spinocerebellar tracts
non-specific ascending pathway
formed by the lateral and anterior spinothalamic tract
transmits pain, temperature, and coarse touch
specific ascending pathway
formed by the dorsal white column
transmits discriminative touch and vibrations
spinocerebellar tracts
fromed by the anterior and posterior spinocerebellar tracts
transmits information about muscle and tendon stretch to the cerebellum which utilises this information to coordinate skeletal muscle movement
what are the descending pathways
direct (pyramidal) system
indirect (Extrapyramidal) system
Direct (pyramidal) system
transmit information down the large corticospinal (pyramidal tract). axons descend from the brain without synapsing with any other until they reach the level they need and communication with neurons in the ventral horn
regulate fast and fine movements e.g. writing
Indirect (Extrapyramidal) system
includes all other descending (efferent) pathways
complex with multisynapses, regulate
-muscles used in balance and posture
-coarse limb movement
-head, neck and eye movement that follows moving objects
what is the somatic nervous system involved in
voluntary movement
sensory input
reflex arc
autonomic nervous system
divided into sympathetic and parasympathetic
involuntary and automatically
innervates all of the internal organs
Sympathetic nervous system
arises from the thoracolumbar region of the spine. the SNS is responsible for our ‘fight or flight’ response
when stimulated it causes:
- increase heartbeat
- dilation of airways
- reduced digestion
- pupil dilation
- inhibits urination
Parasympathetic nervous system
arises from cranial nerves and sacral nerves and promotes all internal responses in a relaxed state
when stimulated it causes:
- promotion of digestion
- constriction of pupils
- slowing of heart rate
- stimulation of urination
blunt injury
forced flexion or flexion with rotation forced extension (hyperextension) vertical compression (axial loading)
penetrating injury
commonly caused by a knife or gunshot
spinal cord is rarely severed
fractures in vertebral column
can occur anywhere in the vertebrae
may not result in spinal cord injury
can result in incomplete or complete SCI
secondary mechanisms of injury to the spinal cord
- systemic hemodynamic changes
- microvascular changes in the cord
- spinal cord oedema (swelling)
- electrolyte shifts
- free radical release
- excitotoxic amino acid release (vasospasm)
ASIA impairment scale
international standards for neurological clasification of spinal cord injury
determines the neurological level of the impairment on both a motor and sensory scale
determines if the injury is complete or incomplete or if there are any zones of partial preservation
central cord syndrome
damage only to the central portion of the cord
arm movement can be affected but leg movement intact
Anterior artery syndrome
caused by an infarction of the main anterior artery affects the anterior two thirds of the cord
loss of motor and major sensory tracts but preservation of proprioception, vibration and touch sensation
brown-sequard syndrome
damage is to one side of the cord only
loss of motor on one side of the body and loss of pain and temperature on the other side
conus and cauda equina injuries
loss of motor function
variable patterns with some recovery potential
lower motor bowel, bladder and sexual function effected
sacral sparing
sensation of sacral area preserved in otherwise paralysed person
upper motor neurons
originate in the brain and travel within spinal cord
injury results in spasticity of limbs and bladder and bowel function
lower motor neurons
originate in spinal cord and travel outside the cord forming the spinal nerves
damage causes disruption of the reflex arc and pathway to communication with upper motor neurons eg flaccid limbs and bladder/bowel function
SCI complications
spinal shock
autonomic dysreflexia
spasticity
heterotopic ossification
spinal shock
immediately after injury and up to approx 6 weeks
temporary depression of all reflex activity
- hypotension
- bradycardia
- hypothermia
autonomic dysreflexia (AD)
potentially life threatening above the lvel of the T6 spinal injury
starts to occur after initial phase of spinal shock, when spinal reflexes return
irritation of the ski, bowel or bladder cause a highly exaggerated response from autonomic nerves caused by the hormone, norepinephrine
this elevates blood pressure, slows heart and causes headaches, nausea, anxiety goose bumps etc which can then cause seizures, cerebral hemmorage and death
inability to sense the irritants is a major cause of this dysreflexia - common caused by an overful bladder, skin irritation, feaces
spasticity
spinal cord injury prevents the brain from telling the muscle to relax
tendons remodel causing permanent muscle shortening or contracture
heterotopic ossification
abnormal deposit of bone in muscles and tendons that may occur after injury
causes localised swelling, warmth, redness, and stiffness of the muscle
begins one to four months after the injury and is rare of one year
assessment and diagnosis of spinal cord injury
CT scan or MRI of the spine
myelogram (xray of the spine after injecting dye)
somatosensory evoked potential (SSEP) testing ot magnetic stimulation
spine xrays
surgery
halo-thoracic brace
stops heads from turning, looking up/down
corticosteroids..
reduce swelling that may damage the spinal cord
