spinal anatomy and injury

Question 1

What is a dermatome

Answer 1

area of skin supplied by a single spinal nerve

Question 2

What is a myotome

Answer 2

Group of muscles that a single spinal nerve innervates

Question 3

Who do spinal cord injuries more commonly affect

Answer 3

males
20-30 year olds

Question 4

What are the common causes of spinal cord injuries

Answer 4

Falls
RTA - road traffic injuries
Sport

Question 5

What are the symptoms of a complete spinal cord injury

Answer 5

No motor or sensory function distal to the lesion
Loss of anal tone
No sensation at the sacrum
no chance of recovery

Question 6

What are the symptoms of incomplete spinal cord injury

Answer 6

Some functions still present distal to the lesion and usually a more favourable prognosis compared to complete spinal cord injuries

Question 7

Describe the asia classification

Answer 7

A-E classification of spinal cord injuries
A - complete spinal cord injuries with no function preserved distal to the lesion

B - incomplete spinal cord injury - sensory function preserved distal to the lesion at the sacrum (motor not preserved)

C - incomplete spinal cord injury - motor function preserved distal to the lesion - muscles have grade less than 3

D incomplete spinal cord injury - motor function preserved distal to the lesion with the majority of the muscles having a grade higher than 3

E - incomplete spinal cord injury with normal motor and sensory function distal to the lesion

Question 8

What level of lesion causes tetraplegia/quadriplegia

Answer 8

Above the innervation to the limbs - results in paralysis of all 4 limbs

Question 9

What level of lesion causes paraplegia

Answer 9

Below the innervation of the arms - causes paralysis of the lower limbs

Question 10

What is tetraplegia (quadraplegia)

Answer 10

Partial or total loss of all 4 limbs and the trunk

Loss of motor and sensory function in the cervical segments of the spinal cord

Question 11

Why can a cervical fracture cause respiratory failure

Answer 11

If the phrenic nerve becomes damaged - (C3-5)

Question 12

What is spasticity

Answer 12

Increased muscle tone

Upper motor neuron lesion

Spinal cord and above (CNS)

Injuries above L1 - termination of spinal cord below that which is mainly just peripheral nerves

Question 13

What are the 3 patial cord syndromes

Answer 13

central cord syndrome
anterior cord syndrome
brown- Sequard syndrome

Question 14

What is paraplegia

Answer 14

Partial or total loss of lower limbs

Impaired sensory and motor function in the thoracic, lumbar or sacral legions

Arm function is spared

Question 15

Who does central cord syndrome more commonly affect

Answer 15

older patients

Question 16

What tracts are more involved in central cord injuries and what is the result of that

Answer 16

centrally cervical tracts are more involved and since the lower limb tracts are more peripheral, there is more weakness in the arms compared to the legs

Question 17

how does central cord syndrome present

Answer 17

Hyperextension injury
weakness of arms more than legs
Perianal sensation and lower extremity power is preserved

Question 18

What causes anterior cord syndrome

Answer 18

Hyper flexion injury that causes an anterior compression fracture

Question 19

how does anterior cord syndrome present

Answer 19

Damaged anterior spinal artery

Fine touch and proprioception preserved

Profound weakness due to lateral corticospinal tract damage

Spinothalamic tract damage so loss of pain and temperature sensation

Question 20

What causes brown-sequard syndrome

Answer 20

Hemi-section of the spinal cord

Question 21

How does brown-Sequard syndrome present

Answer 21

Loss of proprioception and fine discrimination on the same side as the lesion due to the dorsal column crossing over at the hindbrain region above the lesion

Paralysis on same side as lesion due to corticospinal tract crossing over at the hindbrain above the lesion

Pain and temperature loss at the opposite side below the lesion - due to the spinothalamic tract crossing over at the level of the lesion at the spinal cord

Question 22

What is spinal shock

Answer 22

Transient depression of cord function below the level of the injury

causes flaccid paralysis

Areflexia - absence of reflexes

Lasts from hours to days after the injury

Question 23

What is neurogenic shock

Answer 23

Loss of the sympathetic tone
Injuries have to be above T6 because the sympathetic outflow is damaged

The loss of sympathetic tone causes hypotension, bradycardia and hypothermia

Question 24

What are the investigations done for spinal injury

Answer 24

X rays

CT scanning

MRI - if there is neurological deficit or in children

Question 25

What is the preferred surgical fix for stabilising the spine

Answer 25

screws that are passed into the pedicle

Question 26

Which unit are people with spinal injuries admitted to

Answer 26

Spinal cord injury unit