Musculoskeletal Growth Injury and Repair – Peripheral Nerve Injuries Flashcards

1
Q

What are the two units of a nerve…worded that weird but you know it

A

Motor and sensory units

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2
Q

What are the motor units (efferent) and where are they located?

A

Anterior horn cells found in grey matter of spinal cord

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3
Q

What are the sensory units (afferent) and where are they located?

A

Cell bodies in the posterior root ganglia i.e. outside of the spinal cord

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4
Q

Nerve fibres joint to form motor and sensory roots. Are the sensory roots anterior or posterior and ventral or dorsal?

A

Posterior/dorsal roots

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5
Q

Nerve fibres joint to form motor and sensory roots. Are the motor roots anterior or posterior and ventral or dorsal?

A

Anterior/ventral roots

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6
Q

What surrounds larger peripheral nerve fibres?

A

Myelin sheath which provides insulation

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7
Q

What are axons coated with?

A

Endoneurium - type of CT

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8
Q

What are axons grouped together to form?

A

A fascicle

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9
Q

What are fascicles grouped together to form?

A

Nerve

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10
Q

What type of CT covers nerves?

A

Epineurium

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11
Q

What cells surround neurones?

A

Schwann cells

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12
Q

RECAP- which type of fibres travel the quickest?

A

A alpha fibres

->these are the biggest fibres

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13
Q

RECAP- which type of fibres travel the slowest?

A

C fibres

->these are the smaller fibres

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14
Q

Which fibres transmit dull, aching or burning pain and temperature sensation?

A

C fibres

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15
Q

Which fibres transmit sharp pain and light touch?

A

A delta fibres

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16
Q

Which fibres transmit touch, pressure, vibration and join position sensory axons?

A

A beta fibres

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17
Q

Give some examples of direct trauma injuries.

A

Blow or laceration

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18
Q

Give some examples of indirect trauma injuries.

A

Avulsion or traction

19
Q

List some common conditions caused by compression of a nerve.

A

Carpal tunnel syndrome
Sciatica
Morton’s neuroma

20
Q

Which nerve gets compressed in carpal tunnel syndrome?

A

Median nerve

21
Q

Which nerves get compressed in sciatica?

A

Spinal roots by IV discs

22
Q

What nerve get compressed in Morton’s neuroma?

A

Digital nerve in 2nd or 3rd web space of forefoot

23
Q

Neurapraxia?

A

Mild nerve injury in which nerve has been stretched or bruised

Causes conduction block and local ischaemia and demyelination

24
Q

What is prognosis of neurapraxia?

A

Good as reversible, settles after weeks or month

25
Axonotmesis?
More severe than neuropraxia, nerve is more stretched Wallerian degeneration follows
26
What is the prognosis of axonotmesis like?
Fair, sensory recovery is often better than the motor recovery but is still not normal but enough to recognise hot and cold, sharp and blunt etc
27
Neutrotmesis?
Worse than axonotmesis and neuropraxia. Often caused by lactation or avulsion
28
What is the prognosis of neurotmesis like?
No recovery unless repaired by suturing or grafting Poor porgnosis
29
Nerve injuries are be described as being open or closed. Closed nerve injuries are associated with nerve injuries in continuity (whole nerve is still in tact). Give examples
Neuropraxis Axonotmesis
30
How long after closed nerve injuries in surgery indicated?
3 months after as spontaneous recovery in possible
31
What are open nerve injuries usually associated with?
Trauma e.g. knives or glass cutting through a nerve
32
How are open nerve injuries usually treated?
Early surgery
33
What are the clinical features of nerve injuries?
Sensory- numbness and paraesthesia Motor- weakness, paralysis, wasting, dry skin Diminished or absent reflexes
34
Do pure or mixed nerves tend to recover better?
Pure nerves (only sensory or motor)
35
Which sign can be used to monitor recovery in nerve injuries?
Tinel's sign ->tap over nerve site and paraesthesia will be felt as far distally as nerve regeneration has progressed. We do this in clinical skills for carpal tunnel syndrome).
36
How quickly do nerves regenerate?
1mm/day
37
What are the two ways of surgically repairing a nerve?
Direct repair Nerve grating
38
When can nerves be directly repaired?
In laceration if two nerve endings present
39
When is nerve grafting used?
When there is nerve loss of it's a late repair after a few months after injury
40
Injuries to peripheral and central NS can both cause loss of motor or sensory function or both. So how can we tell the difference clinically?
UMN vs LMN lesions as in UMN lesions, the peripheral nerve is still intact
41
RECAP- UMN lesion findings?
Decreased strength Increased tone Increased reflexes Present Babinski's sign Clonus
42
REACP- LMN lesion findings?
Muscle atrophy Decreased reflexes Absent Babinski's sign
43