Physiology - Spinal disorders

Question 1

Upper motor neurone pathology

Answer 1

Spasticity – pt’s will have stiff muscles w/ brisk tendon reflexes
Normal peripheral nerves

Question 2

Where do lower motor neurones start

Answer 2

Start at anterior horn cell body

Question 3

Lower motor neurone pathology

Answer 3

Flaccid paralysis, lost tone and power

Loss of axons or peripheral nerve cell body

Question 4

Sensory function nerves

Answer 4

Discriminative touch

Pain and temperature

Question 5

Discriminative touch

Answer 5

Ability to distinguish objects, shapes, surfaces, textures with skin. Provided by large, myelinated nerve fibres

Question 6

Pain and temperature - sensory nerves

Answer 6

Provided by small, unmyelinated nerve fibres

Question 7

What does the effect of denervation depend on

Answer 7

Where the damage is

Question 8

The most common effects of denervation are

Answer 8

Loss of function in root distribution

Loss of function in distribution of named nerve

Question 9

Pathology of peripheral nerves resulting in denervation

Answer 9

Pathology of myelin, if severe enough will lead to secondary axon damage
Pathology of axons
Infl of blood vessels e.g. vasculitis can also damage axons

Question 10

Epineurium

Answer 10

Membrane surrounding nerve

Question 11

Perinuerium

Answer 11

Membrane surrounding fascicle

Question 12

Things that can go wrong leading to axon damage

Answer 12

Damage to myelin – acquired or inherited

Direct injury to axons from toxins or metabolic disturbance or secondary axonal damage due to demyelination

Question 13

Causes of damage to axons - trauma

Answer 13

Compression e.g., carpal tunnel syndrome or ivd prolapse
Transection e.g., knife wound
Stretching

Question 14

Causes of damage to axons - disease (peripheral neuropathy)

Answer 14

Diabetes, B12 deficiency 
Infl, autoimmune 
Infection, HIV, Leprosy 
Drugs and toxins 
Inherited

Question 15

Length dependent peripheral neuropathy

Answer 15

Loss of function affects most distal parts of body first

Question 16

Non-length dependent peripheral neuropathy

Answer 16

Loss of function occurs in patches and can affect short and long nerves

Question 17

Radiculopathy

Answer 17

Damage of nerve root

Question 18

Types of axon loss

Answer 18

Axonotmesis
Neurotmesis

Recovery of both requires axon regrowth - 1mm/day

Question 19

Axonotmesis

Answer 19

Damage of few axons, can recover but slow and may be incomplete

Question 20

Nuerotmesis

Answer 20

Complete transection of nerves, recovery requires grafting transected ends

Question 21

Neuropraxia

Answer 21

damage to nerve in the form of myelin, temporary and reversible

Question 22

Recovery of myelin damage

Answer 22

8-12 weeks after removal of cause

Question 23

Wallerian degeneration

Answer 23

When an axon has been cut, calpain gets released which is activated and breaks down components of nerve over 3 days before macrophages move in and clear debris.

Question 24

Reinervation after Wallerian degeneration

Answer 24

The ends of the axon still attached to the cell body will start to regenerate

Question 25

Effects of denervation on sensory nerves

Answer 25

Altered sensation

Numbness
Pain due to loss of axons supplying discriminative touch
Paresthesia - axons that are hyperexcitable

Question 26

Effects of denervation of motor nerves

Answer 26

Atrophy
Weakness
Paralysis

Question 27

Effects of denervation in muscles

Answer 27

Begin to waste – atrophy

Begin to generate spontaneous motor activity

Question 28

Spontaneous motor activity as a result of denervation

Answer 28

Fibrillations and fasciculations

Cramps

Question 29

Muscles viability without nerve supply

Answer 29

Up to 2 yrs

After which they fibrose and can’t return to normal function