Spinal Cord & Spinal Injuries Lecture

How many pairs of spinal nerves are there?

31

what does grey matter contain?

neuronal cell bodies

what does white matter contain?

myelinated axons

what can the white matter be further subdivided into?

ascending or descending tracts

what does the trcts tansmit?

sensory information or motor information

Where does the spinal cord end?

below the L1 and L2 vertebra

what is cauda equina (horses tail)?

spinal nerves exiting beyond the point where the SC ends

the SC is covered by the 3 main meningeal layers as the ___.

brain

the pia mater is attached to the _____.

spinal cord

where does the meningeal covering of the SC extend past?

end of the SC to the L4 level

what is the CFS filled meningeal space between L2-L4 referred to as?

lumbar cistern

what are the two main functions of the spinal cord?

• carries sensory information from your environment to your brain where it is processed

• contains spinal reflexes

information carried to the brain is:

afferent pathways (ascending tracts)

information that exits the brain is by:

efferent pathways (descending tracts) which results in movement

information is carried on pathways called:

nerve tracts

what makes information to the brain from the spinal cord travel quickly?

myelinated axons, which increase conduction speed.

UMN

nerve cell loacted in the brain’s cerebral cortez that sends signals to initiate voluntary movemnt (create the plan of movement)

LMN

nerve cell loacted in the spinal cord that directly connects to muscles and carries the signal form the UMN to produce movement (execute the plan)

what results in a motor output thay is not cognitively processed?

spinal reflex arc

Dorsal columns is responsible for what?

touch, pressure, vibration, and proprioception

what does the lateral spinothalmic tracts do?

carries conscious sensory information to the cortex on the opposite side of the body (ie pain and temprature)

what does the posteriorir spinocerrebeollar do?

does not decussates, so injuries remain ipsilateral

what does the spinocerebellar tracts do?

unconscious proprioception

what tracts are ascending (sesnory)?

• dorsal columns

• lateral spinothalmic tracts

• posterior spinocerebellar

• spnocerebellar tracts

what are the descending tracts (motor)?

• lateral corticospinal tract

• vestibulospinal tracts

what are the features of the lateral corticospinal tract?

• the longest tract

• responsible for volitional motor control of the opposite side of the body

• motor signals from the primary motor cortex in the brain, down the spinal cord, to the muscles of the trunk and limbs

where does the vestibulospinal tracts originate in?

the brainstem

what does the vestibulospinal tratc do?

facilitates extensor tone; these muscles support adequate upright sitting posture

ways the spinal cord can be injuried:

• transection

• compression

• infection

• degenerative disorder

transection SC injury:

complete severance of the cord; interuption of all sensory and motor information below the lesion

• can result from traumatic injury: MVA, knife wounds, gunshot, diving & sport/recreation accidents

compression SC injury:

impingement of the cord from trauma, tumor, or vertebral DJD

infection SC injury:

may compronis the integrity of the cord: damage to the cellbodies inthe ventral horn causing LMN loss

degenerative disorders (SC injury):

degenerative disease can damage the motor SC tracts; ALS; bulateral degenration of the ventral horn and pyramidal tracts; involves both UMN/LMN

what is spinal shock?

absence of spinal reflexes, reduced muscles tone, paralysis

what is the resolution of spinal shock?

spasticity, return of motor function and sensation, hyperreflexia, presence of primary reflexes such as the Babinski

how many phases are there of spinal shock?

4

how long is phase 1 of spinal shock?

0-1 day

how long is phase 2 of spinal shock?

1-3 days

how long is phase 3 of spinal shock?

1-4 weeks

how long is phase 4 of spinal shock?

1-12 months

Motor & sensory level injury class:

may not be the same (ie pateint may have sensation intact at as low as T1, but only motor control up to C3)

Neurological level injury class:

cervical injury causing sensory and/or motor loss to all four limbs, trunk, bowel & bladder control

Paraplegia injury class:

impairment or loss of motor and/or sensory function in the thoracic, lumbar, or sacral segments of the spinal cord; UEs are genrally unaffected

complete SC injury class:

no motor or sensory function below the level of injury

incomplete SC injury class:

some sensation or motor is still present below the level of injury (have better prognosis)

the higher the spinal cord injury:

the more impact on the body

what are the stages of the ASIA impairment scale?

A = complete, B = sensory imcomplete, C = motor incomplete, D = motor incomplete, E = normal

Stage A description (ASIA impairment scale)

no sensory or motor function preserved in the sacral segments S4-S5.

Stage B description (ASIA impairment scale)

sensory function preserved below the neurological level, but no motor function preserved.

Stage C description (ASIA impairment scale)

motor function preserved below the neurological level, and more than half of the key muscles below the level have a muscle grade less than 3.

Stage D description (ASIA impairment scale)

motor incomplete status as defined above, with at least half (half or more) of key muscle functions below the single NLI having a muscle grade > or equal to 3

Stage E description (ASIA impairment scale)

if sensation and motor function as tested with the ISNCSCI are graded as nromal in all segments, and the patient had prior deficits, then the AIS grade is E. Someone without an initial SCI does not recieve an AIS grade

upper motor neuron lesion

leads to spacisity below the site of the lesion and flaccidity at the lesion site

lower motor neuron lesion

leads to flaccidity, hypo-reflexia, and muscle atropy

what is Autonomic Dysreflexia?

occurs after a SCI; spike in blood pressure due to a noxious stimuli below the level of the lesion; can be life threatening

what are the signs and symptoms of autonomic dysreflexia?

• bradycardia

• severe hypertension

• severe headache

• vasodilation

• flushed skin

• profude sweating

what are thr precautions of autonomic dysreflexia?

• do not recline or lay patient down

• keep them upright to maintain consciousness

what does the sympathic nervous system make the body do?

• dilate pupils

• inhibits selvation

• release bronchi; increase HR

• inhibits digestive activity

• stimulates glucose release by the liver

• stimulates epinephon and nonepinephion

• relaxes bladder

• organs, ejaculation, contracts rectum

what does the parasymoatheic nervous system do to the body?

• contracts pupils

• stimulates salvation

• constricts broncho, decreases HR

• stumlates digestive activity

• stimulates gallbladder

• inhibition of adrenaline production

• contracts bladder

• relaxes rectum

what can happen with a SCI?

body temperature dysregulation

what is edema?

the pulling of fluids; results in immobility

what does edema cause?

increase vein pressure, abdnormal pooling of blood in abdomen, legs, and arms

what is orthostatic hypotension?

sudden drop in blood pressure when pt moves from sit/laying down to sitting up/standing

orthostatic hypotension is common in and SCI at what part of the spinal cord?

T6 and above

what is deep bein thrombosis?

clots in the legs that can travel to the lungs, causing pulmonary embolissm

what is central cord syndrome?

A type of incomplete spinal cord injury that primarily affects the upper extremities more than the lower extremities, often seen in older adults.

what is brown-sequard syndrome?

A type of incomplete spinal cord injury characterized by hemisection of the spinal cord (only one side), resulting in ipsilateral motor loss and contralateral loss of pain and temperature sensation

if the lateral corticospinal tract is lost:

ipsilateral loss of motor control and spasticity below the lesion level

if dorsal columns are lost:

Contralateral loss of pain and temperature sensation below the lesion level; ipsilateral loss of touc, vibration, and proprioception

if sipinothalmatic tract is lost:

contralaterally, pain and temperature lose belwo the lesion level and at the lesion level bilateral loss

what is anterior cord syndrome?

damage to the anterior portion of the spinal cord, leading to loss of pain and temperature sensation below the level of injury, while proprioception and vibration sense remain intact.

what is conus medullaris syndrome?

A condition resulting from damage to the conus medullaris, causing lower limb weakness, loss of bladder and bowel control, and sensory loss in the saddle region.

what is cauda equina syndrome?

A condition resulting from injury to the cauda equina, leading to lower back pain, leg weakness, loss of sensation in the legs, and bowel and bladder dysfunction. (can happen from a herniated disc or tumor that causes the compression, or can just happen)

what happens when there is a lesion at C1-C4?

can result in quadriplegia, loss of respiratory function, and impaired sensation and motor control in the upper and lower limbs; most severe

what happens when there is a lesion at C5-C7?

can lead to partial loss of function in the arms and hands, resulting in weakness in shoulder and elbow movements, while allowing some hand function.

what is tenidesis?

A functional movement pattern where wrist extension creates passive finger flexion, allowing individuals with spinal cord injuries to grasp objects.