peripheral nerve injuries

Question 1

What is another name for motor root

Answer 1

ventral root

Question 2

What is another name for a sensory root

Answer 2

dorsal root

Question 3

Where do the cell bodies of motor units lie

Answer 3

The grey matter of the spinal cord

Question 4

Where do the cell bodies of sensory units lie

Answer 4

dorsal root ganglia

Question 5

What forms a spinal nerve

Answer 5

Ventral and dorsal root combining

Question 6

Where do the spinal nerves leave the spine

Answer 6

Intervertebral foramen

Question 7

What surrounds peripheral nerves

Answer 7

schwann cells

Question 8

Describe the structure of a peripheral nerve

Answer 8

Axons that are covered in endoneurium - grouped into fascicles (nerve bundles) which are covered in perineurium - these are grouped into nerves which are covered in epineurium

Question 9

What is the fastest type of neuron fibre

Answer 9

Alpha

Question 10

What is the slowest type of nerve fiber

Answer 10

C

Question 11

What is the correlation between size and speed of transmission

Answer 11

the larger the fibre, the faster the speed of transmission

Question 12

What can compress nerves and give examples

Answer 12

Entrapment
Carpal tunnel syndrome - median nerve compression
Sciatica - intervertebral disc compresses sciatic nerve
Morotons neuroma - digital nerves in web space are compressed

Question 13

What is neurapraxia

Answer 13

Reversible conduction block caused by trauma which causes local ischaemia and demyelination which then leads to the neurapraxia

Question 14

What is wallerian degeneration

Answer 14

Degeneration of the distal end of an axon

Question 15

Does the tube remain intact in axonotmesis

Answer 15

Yes because the endoneurium is intact

Question 16

What happens in neurotmesis

Answer 16

division of the nerve

Question 17

What are closed nerve injuries associated with

Answer 17

the nerve is still continuous and intact
Neuropraxis and axonotmesis

Question 18

When is surgery indicated in closed nerve injuries

Answer 18

If no recovery has been identified after 3 months

Question 19

What nerves commonly get damaged with closed nerve injuries

Answer 19

Brachial plexus and radial nerve

Question 20

What type of injury are Open nerve injuries associated with

Answer 20

Associated with nerve division - neurotemesis

Question 21

What is a common cause of open nerve injury

Answer 21

Accidental cut of the hands with knife

Question 22

What is the treatment for open nerve injury

Answer 22

Early surgical intervention

Question 23

What are the sensory clinical features of nerve injury

Answer 23

Dysaethesiae - disordered sensation - anaesthetic, hypo and hyper-aesthetic or paraesthesia(pins and needles)

Question 24

What are the motor clinical features of nerve injury

Answer 24

Paresis - weakness
Dry skin - nerve not stimulating sweat glands in skin
Diminished or Absent reflexes due to no preipheral nerve

Question 25

How fast is the regeneration of a nerve

Answer 25

1mm/day

Question 26

What is the first function to return in nerves

Answer 26

pain

Question 27

Does a pure or mixed nerve have better recovery and why

Answer 27

Pure because it is all one type of nerve (sensory or motor) so they all regenerate back to one end plate

Question 28

Is nerve healing better for a distal or proximal injury

Answer 28

distal - due to degeneration of the end plates when it is further which is why proximal is not as fast at healing

Question 29

What is tinnel's sign

Answer 29

Tap over sign and paresthesia will be felt as far distally as regeneration has progressed

Question 30

How can nerve injury be assessed and healing can be monitored

Answer 30

Electrophysiological nerve conduction studies

Question 31

What injuries require direct repair

Answer 31

laceration no loss of nerve tissue

Question 32

When is nerve grafting done

Answer 32

When there is nerve loss - due to damage or retraction where the nerve endings cannot be pulled together

Question 33

What happens in nerve grafting

Answer 33

unuseful nerve such as the sural nerve is used and stitched at either end to the nerve endings - provides a passage for the axons to grow down

Question 34

What is the rule of three

Answer 34

The surgical timings of traumatic peripheral nerve injury

Question 35

Describe the rule of three

Answer 35

Immediate surgery within 3 days for clean and sharp injuries Early surgery within 3 weeks for blunt/contusion injuries Delayed surgery within 3 months for closed injuries

Question 36

What are the signs in upper motor neuron lesions (central)

Answer 36

Still have peripheral nerves therefore decreased strength Increased tone and deep tendon reflex present clonus and babinski no atrophy

Question 37

What are the signs in lower motor neuron lesions (peripheral nerve)

Answer 37

decreased strength, tone and deep tendon reflex Absent clonus and babinski Atrophy is present