Week 9 - Spinal Cord Injury Flashcards
what is the cervical plexus formed from (2)
- C1 to C5
- CN 6 and 7
what does the cervical plexus create (4)
nerves that innervate the
- neck (sternocleidomastoid)
- shoulder
- chest
- trapezius
what is the phrenic nerve
- nerve that innervates the diaphragm
what are the 4 plexus
- cervical
- brachial
- lumbar
- sacral
what is the brachial plexus formed from
- formed from ventral rami of C5 to T1
what does the brachial plexus innervate
- arm & chest
what is the lumbar plexus formed from
- L1 to L5
what does the lumbar plexus innervate (4)
- abdominal wall
- hip flexors
- thigh
- genital regions
what is the sacral plexus formed from
- L4 to S4
what does the sacral plexus innervate (5)
- buttocks
- lower limbs
- pelvic regions
- genitals
- anus
what are common causes of spinal cord injuries (SCI) (2)
traumatic events that causes:
- fracture
- dislocation of the vertebrae
what are other causes of SCI (2(
- ischemia
- necrosis
where do most SCI occur in
- cervical & lumbar regions (areas that provide more mobility)
where do penetrating wounds occur
- can occur anywhere in the column
what are 4 leading causes of SCI
- motor vehicle accidents (#1)
- falls
- violence
- sports injuries
with aging, what becomes the most frequent cause of SCI (2)
- falls
- also osteoporosis is a contributing factor
what are contributing factors to SCI in youth (2)
- alcohol
- drugs
which sex are SCI more common in
- males
is SCI temporary or permanent
- can be either
- but neurons in the CNS do not regenerate adequately = some degree of permanent loss is usually present
what does complete transection of the spinal cord cause
- loss of all neural transmission to & from the brain below the cut
what does transection of motor tracts cause (2)
- paresis
- or paralysis
what does transection of sensory tracts cause
- paraesthesia
what do partial transections cause
- patterns of functional loss related to the specific tracts destroyed
describe the effect spinal cord transections have on spinal cord reflexes
- most remain intact
- and many are exaggerated (Hyperreflexia)
why are many spinal cord reflex exaggerated after SCI
- bc “descending” inhibition from the brain is lost
what is spinal shock
- in the initial period after injury, all neural activity below or slightly above the site of injury ceases
what effect does spinal shock have on BP
- drops
how long might spinal shock last
- days to weeks
what is spinal shock characterized by (4)
- flaccid paralysis
- sensory loss
- arflexia
- absence of central control of autonomic functions
what is areflexia
- absense of all reflex responses
what occurs after recovery from spinal shock
- spinal reflex return
what is spinal reflex return characterized by (3)
- spastic paralysis
- reflex urinary incontinence
- reflex defecation
what do cervical SCIs commonly occur from (2)
- hyperflexion & hyperextemsion trauma of the neck
what are 2 common causes of a cervical SCI
- MVA
- fall
where does the phrenic nerve originate from?
- C3 to C5
damage to C5 or above requires…
- ventilator assistance
what are both cervical & thoracic nerves responsible for
innervating accessory muscles of breathing like
- sternocleidomastoid
- intercostal muscles
what does damage above the cervical & thoracic areas cause (3)
- shallow breathing
- weak cough reflex
= pooled resp secretions
what are the arms innervated by
- brachial plexus (C5-T1)
what does damage above C5 cause r/t motor function
- quadraplegia/tetraplegia
what is quadraplegia/tetraplegia
- paralysis of all four limbs
what does damage within the brachial plexus (C5-T1) cause r/t motor
- incomplete loss of function in arms (paresis)
what does damage below T1 cause r/t motor function
- paraplegia
what is paraplegia
- impairment of motor and/or sensory function in lower extremities
what do cervical SCIs result in (4)
- no sensation
- no voluntary movement
- no central control of SNS
- autonomic reflexes present, but with no voluntary control (incontinence)
what is autonomic dysreflexia; what does it occur w?
- occur w a T6 or above SCI
- where the NS overreacts to stimuli
- sensory stimulus triggers a massive & exaggerated SNS reflex that cannot be controlled by the medulla
what does autonomic dysreflexia result in (3)
- increased vasomotor tone
= increased BP
= HA
= baroreceptors decrease HR
what happens if autonomic dysreflexia goes unnoticed
- heart failure
- MI
- CVA
may occur
what often causes lumbar SCI
- compression fractures when a force is applied to the head, coccyx, or feet
what is required for lumbar SCI to occur? what makes it more likely?
- great force required
- but osteoporosis makes it more likely
what does damage to the cord above L1 cause
- paralysis of the legs = paraplegia
what does damage to the cord below L1 cause
- paresis of the legs
where does PSNS innervation of the bladder & bowel region originate from
- sacral region
what effect can cord damage have on the bladder & bowel & genitals
- loss of voluntary control of the bladder & bowel
- erection can occur but may be difficult to maintain
what is do incomplete transections result in
- results in tract & gray matter specific loss of function
what does damage to one side of the cord cause (4)
contralateral loss of
- pain
- temp sensation
ipsilateral loss of
- touch sensation
- paresis
why do we get contralteral loss of pain & temp sensation w an incomplete transection
ascending tracts for pain & temp cross over at the spinal cord level where they enter
why do we ipsilateral loss of touch & paresis w an incomplete transection
- cross over in the medulla
damage to the right side of the cord can cause..
- damaged pain & temp sensation to the L side of the body
- damaged touch and pressure senation, & motor control to the right side of the body
what are complications of SCI usually secondary to
- immobility
- paralysis
- paresis
what are 7 complications of SCI
- pressure ulcers
- resp tract infections
- UTI
- gastric stress ulcers
- contractures
- DVT
- chronic pain
what causes resp tract infections r/t SCI (4)
- immobility
- impaired, shallow respirations
- paresis of secondary resp muscle
- weak cough reflex
what causes UTI r/t SCI
- urinary retention due to spinal shock
- paresis of secondary muscles involved in micturition
what are contractures
- spastic reflexes involving skeletal muscle may cause contracted muscle that fail to reflex
what can cause DVT r/t SCI
- immbolity
- pressure can cause venous stasis
what are risks of DVT
- pulmonary embolism
what does chronic pain more frequently occur in r/t SCI (2)
- incomplete transection
- paraplegia
pain may initially occur due to
- fracture of the vertebra
pain may persist as…
- radiating pain
- visceral pain
- central pain
who do chronic pain cycles often effect
- people who have been immobilized for a long period of time
