Spinal Cord anatomy and conditions

Question 1

Motor Conditions

Answer 1

Amyotrophic lateral sclerosis
Poliomyelitis

Question 2

ALS area affected?

Answer 2

affects both upper (corticospinal tracts) and lower motor neurons
results in a combination of upper and lower motor neuron signs

Question 3

Do UMN innervate ipsilateral or contralateral muscles

Answer 3

contralateral

Question 4

Do LMN innervate ipsilateral or contralateral muscles

Answer 4

ipsilateral

Question 5

Why do lower motor neurone signs occur the way they do?

Answer 5

loss of trophic effect on muscles

Question 6

What are the LMN signs?

Answer 6

weakness
wasting
fasciculation
hypotonia
hyporeflexia

Question 7

Why do upper motor neurone signs occur the way they do

Answer 7

Occur due to hyper excitability of inputs to anterior horn cells

Question 8

What are the UMN signs

Answer 8

weakness - extensor weakness in upper limbs and flexor weakness in Lower limbs

no wasting
hypertonia, spasticity
hyperreflexia
loss of fine motor movement
pronator drift
extensor plantar response
clonus

Question 9

What are the ddx for LMN lesions

Answer 9

ventral horn pathology - MND, post-polio
peripheral nerve pathology
NMJ pathology
Muscular pathology

Question 10

What are the dx for UMN lesions

Answer 10

Vascular: stroke
Inflammatory: MS, MND
Neoplastic: Tumour
Degenerative: Parkinson’s
Infective: Post-meningitis
Extra: drugs

Question 11

What are the descending tracts?

Answer 11

MOTOR:

Dorsal and ventral CORTICOSPINAL TRACTS

Question 12

are the corticospinal tracts contralateral or ipsilateral?

Answer 12

ipsilateral as they decussate in the brainstem

Question 13

What is the function of the corticospinal tract?

Answer 13

transmit motor axons from the motor cerebral cortex to the spinal spinal cord

Question 14

What are the ascending tracts?

Answer 14

SENSORY:
dorsal columns
spinothalamic tract (lateral and ventral)

Question 15

What is the function of the dorsal columns?

Answer 15

Transmit deep touch, joint position and vibration to the parietal cortex

Question 16

Are the dorsal columns ipsilateral or contralateral?

Answer 16

ipsilateral - decussate in the brainstem

Question 17

What is the function of the spinothalamic tract?

Answer 17

transmits pain, temperature and light touch to the thalamus

Question 18

Is the spinothalamic tract ipsilateral or contralateral?

Answer 18

contralateral
decussates at the spinal level

Question 19

What clinical syndrome would arise from a cord transection at C3?

Answer 19

Neurogenic shock
Respiratory insufficiency
Quadriplegia
Anaesthesia below the affected level
Loss of bladder/bowel sphincter tone
Sexual dysfunction
Horner’s syndrome

Question 20

What clinical syndrome would arise from a cord transection at T10?

Answer 20

Paraplegia
Anaesthesia below the affected level
Loss of rectal / bladder sphincter tone
Sexual dysfunction

Question 21

What clinical syndrome would arise from a cord hemisection / BROWN SEQUARD

Answer 21

Ipsilateral reduced power (corticospinal tract), vibration and proprioception (posterior or dorsal column)

contralateral reduced pain / temperature and light touch (spinothalamic tract).

Question 22

What is the most common cause of a brown sequard syndrome?

Answer 22

Penetrating injury or facet dislocation in a RTA

Question 23

What is the effect of a posterior cord lesion (loss of dorsal tract)

Answer 23

tingling, numbness, electric shock like syndrome
clumsiness
on examination: sensory ataxia, loss of positional sense, vibration sense and 2-point discrimination below the level of the lesion

Question 24

Brown-sequard syndrome