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Musckuloskeletal > Peripheral Nerve Injuries > Flashcards

Peripheral Nerve Injuries Flashcards

1
Q

anatomy of nerve

A

-Motor nerve- efferent, ventral

Sensory nerve- afferent, dorsal

Autonomic nerve- control vasodilation, sweat, non voluntary components

*the amount of nerve fibers depends on the function of the nerve depends on if a motor, sensory, or mixed nerve (size of the nerve also gives us a clue (ulnar nerve is smaller than median nerve(.

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2
Q

Motor nerve fibers

A
  • originate from the ventral horn of the spinal cord and terminate at motor end plate located in the muscle.
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3
Q

Sensory nerve fibers

A

-originate from the dorsal root ganglia and terminate as free nerve endings

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4
Q

peripheral nerve anatomy

A

axons- are the small tiny dots located within the nerve. (can measure up to 3 ft or more in length)

Peripheral nerve- actually bundles of bundles of axons

Fascicles- one of the bundle of axons within a peripheral nerve.

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5
Q

Epineurium

A
  • outermost layer of a nerve

- Cushions from external pressure and allows movement.

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6
Q

Perineurium

A

-Connective tissue that make up the wall of the fascicles (bundles).

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7
Q

Endoneurium

A

-surrounds individual nerve fibers/supports and protects the individual axons.

Surgical intervention-
-microvascular surgery to line up fascicles.

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8
Q

Mesoneurium

A

=slick loose connective tissue
-facilitates gliding

*peripheral nerves require extraordinary mobility in relation to surrounding tissues, sometimes sliding up to 2 centimeters as we move. This is because nerves are long (they are made up of the longest cells in our body) and often cross joints some distance from the axis of motion.

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9
Q

what makes a nerve happy

A
  • space
  • movement
  • limited sustained tension
  • good blood flow
  • lots of oxygen (20% of all that we breathe)
  • good nutrition
  • stimulation
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10
Q

movement and nerve health

A
  • improves blood flow
  • facilitates gliding of fascicles and nerves
  • Facilitates axoplasmic transport
  • movement prevents “wrinkling” of axons within the endoneurium
  • if they stay in one position they fold up on themselves and cannot glide freely
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11
Q

myelin sheath

A
  • schwan cells produce myelin sheath and wrap around axon

- nodes of ranvier aids in fast conduction

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12
Q

unhappy nerves

A
  • nerves do not like to be held in stretch for prolonged periods of time
  • overstretch can cause traction injuries
  • Compression- resting arm on end of desk while typing or resting on steering wheel.
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13
Q

effects of prolonged compression and stretch

A
  • Blood flow to the nerve comes to a complete standstill at 50-70 mm Hg of pressure or more than 15.7% stretch of the nerve.
  • at 8% elongation the blood flow begins to stop.
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14
Q

vibration

A
  • nerves are sensitive to vibration. a little is good but too much causes damage.
  • recommend people that experience a lot of vibration with job to wear shock absorbing gloves or have handles that absorb the vibration.
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15
Q

Dysfunction of peripheral nerves

A

Sensory changes

  • decreased
  • absent
  • Abnormal sensation (allodynia, ectopic foci)

Autonomic changes

  • loss of sweating or an increase in the amount of sweating
  • loss of “shunting” from superficial capillaries
  • other (if cast is too tight, body may increase hair growth but the hair will go away)
  • want to work on desensitization right away so that they don’t develop a pain syndrome
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16
Q

Dysfunction of peripheral nerves

A

Motor changes

  • Paresis
  • Paralysis
  • If denervation (atrophy of denervation, fibrillations)
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17
Q

various types of nerve injuries

A
  • Avulsion- nerves will pull away from insertion site or the spinal cord at the root.
  • Laceration- partial or complete cut of nerve fibers
  • Compression- can also be caused by ganglions (tumors or osteocytes)
  • Crush injury
  • Edema or ischemia- cause compression and inhibit gliding
  • Traction
  • Radiation
  • Chemotherapy
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18
Q

Classification of Neuropathies

A
  • Mononeuropathy (one, carpal tunnel)
  • Multiple mononeuropathy (several, CTs and cubital, also known as double crush. means there are two different things going on.

-Polyneuropathy (many, diabetic) stocking and glove
(symmetric involvement of sensory, motor, and autonomic axons)

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19
Q

How severe

A
  • Myelinopathy
  • Traumatic Myelinopathy (modality gated and ligand-gated channels may appear in membrane)

Traumatic Axonopathy-

Neurotmesis- severance (complete cut)

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20
Q

Myelinopathy

A
  • axon is preserved- axon is fine
  • no Wallerian degeneration- deterioration past point of injury
  • local demylenation
  • local conduction block
  • full recovery expected
  • my arm’s asleep
  • tingling numbness
  • crossing legs in a movie theatre
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21
Q

Stage 1- Neuropraxia (mild injury)

A

-Pathology (nerve intact, conduction impaired)

Recovery

  • reversible
  • excellent prognosis
  • may not have Tinel sign (only if myelin is disrupted)
  • Sensory loss present, but minimal

Therapy implications

  • Short term, focused
  • Good response to conservative treatment
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22
Q

Stage 2- Axonopathy

A
  • interruption of axons/myelin sheath
  • Wallerian degeneration- below injury is degeneration
  • Good prognosis- as long as fascicle is intact (because it has a path to travel and can meet its connecting part)
  • Healing through axonal sprouting guided by the neural tube.

*injury goes into the axons- interruption in the axons carrying the impulses.

Recovery

  • 1” a month
  • prognosis good

Therapy implications

  • education (avoid what causes problem)
  • moderate intervention (education, tendon and nerve glides, splinting, etc.)
  • Maintain good PROM
  • Follow protocols if post-op- can create tunnel so the axon knows where to go- for lacerations
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23
Q

Stage 3- Neurotmesis

A
  • Loss of axon and endoneurial tube continuity. nerve completely severed.
  • Most sever type of nerve injury. May require surgical intervention
  • In surgery they check to see if they can get firing of the muscle tissue at the end plate for motor nerves. If the muscle doesn’t fire the prognosis is worsened. Muscles atrophy and develop fatty striations and fibrosis.

Pathology

  • nerve completely severed
  • spontaneous recovery impossible
  • Wallerian degeneration

Recovery

  • See the loss of sensory, motor and sympathetic function
  • prognosis better for sensory return than motor

Therapy implications

  • Long term, comprehensive care-
  • a lot of training and re-education (tendon may have used to flex the thumb and now it has to extend it.
  • have to have medical intervention.
  • usually requires surgery.
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24
Q

Axon regeneration

A
  • muscles typically begin to atrophy at 3 months post injury/compression
  • irreversible muscle fibrosis occurs by 24 months
  • there is an 18 day delay before nerve conduction will produce a contraction, after re-establishing the neuromuscular junction.
    • 5 more days for functional reflexes.
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25
Q

Thoracic Outlet Syndrome

A
  • Often misdiagnosed as carpal tunnel and cubital tunnel.
  • Involved the brachial plexus- comes out of C5-T1
  • If you have tight scalenes it can put compression on the brachial plexus. Results in tingling, numbness, weakness, pain.
  • Sometimes there is a problem with the first rib- sometimes the ribs get hung up and stay up and we have to help them stay down in the right position.

Pec minor can be problematic- fibers run up and down- need to elevate and retract shoulders to properly stretch without stretching the brachial plexus.

*posture is super important (breast implants are a huge issue for thoracic outlet syndrome.

  • can have ulnar symptoms
  • posterior dislocated sternoclavicular joint is life threatening because of all the crucial structures located behind it.
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26
Q

Correct posture

A
  • use caution with stretches
  • progressive stretching is best
  • improve forward rounded posture
  • improve pelvic alignment
  • Strengthen abdominal muscles
  • Foam roller or towel between the shoulder blades while lying supine on floor.
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27
Q

Ulnar nerve entrapment

A
  • Cubital tunnel
  • Guyan canal

Ulnar nerve- DermatomeC8

28
Q

Ulnar nerve

A
  • gives us most of the fine motor movement in the hand- pinching and fine motor actions of hand.
  • goes behind the funny bone

Classic cubital tunnel- Numbness and tingling of ring and tiny finger. Can get weakness or loss of pinch/grasp

Needs a detailed clinical assessment for diagnosis and then will to an electrical assessment for diagnosis as well.
(Nerve test is 80% accurate, can have false positives and false negatives)

29
Q

Ulnar nerve treatment

A

Treatment- rest, NSAIDs, ergonomic modifications, night brace (most important=pillow brace, keep the arm from bending at night), surgery (if conservative treatment fails- go in and open up the sources of compression on the cubital tunnel. Transposition procedures- the nerve is decompressed and then moved over the epicondyle (either below the muscle or above the muscle- move nerve from original bed and puts it above or below the muscle (important for overhead athletes=below the muscle to protect the nerve))

  • third procedure- decompressing the nerve and then remove half of the funny bone (medial epicondylectomy)- to remove part of the heel the nerve has to move over but don’t want to remove too much of the bone. (90% success rate and about 2 to 3 months recovery time)
  • after surgery- place in long arm splint- leave room for fingers to move.
30
Q

Cubital Tunnel Syndrome

A
  • “funny bone”
  • Compression/injury of the ulnar nerve between the medial epicondyle and olecranon
  • There are 5 areas of compression in the elbow alone
  • Subluxation: popping in and out of the canal during elbow flexion and extension
31
Q

Cubital Tunnel Syndrome- Therapeutic Intervention

A
  • Patient education: activity modification and pathology
  • Instruct to “keep elbows slightly extended but not locked”
  • avoid direct forces
  • wear elbow pad 1-2 months post d/c
32
Q

cubital tunnel- intervention: 0-6 weeks

A
  • elbow pad for protection
  • static night elbow splint with elbow at 35-60 deg. flexion (wear three months)
  • Pt. ed. to avoid repetitive flexion and extension of elbow, prolonged flexion of elbow, and direct flexion of elbow, and direct pressure to medial posterior aspect of elbow.
33
Q

Guyon’s Canal Syndrome

A

-Compression of the ulnar nerve between the hook of hamate and the volar carpal ligament.

Symptoms:

  • Tenderness over pisiform
  • pain with wrist extension
  • Numbness and tingling in the ring and small finger
  • Decreased grip/pinch strength
  • Weakness in finger ab and adduction

*Ulnar nerve is the main source of power in the hand.

  • FDP- distal phalanx of ring and small finger will be strong- helps us differentiate between cubital tunnel and Guyon’s canal- branch that does motor function for that comes off is not affected.
    • if weak in FDP it is cubital tunnel and not Guyon’s Canal

-FDP branches off at proximal forearm which is affected with cubital tunnel but is not affected with Guyon’s Canal because it is at the wrist and the FDP branches off before that.

34
Q

Guyon’s Canal intervention

A

Splinting
-wrist neutral

Therapeutic Intervention

  • ACUTE- rest, ice, elevation
  • SUB ACUTE- Gentle AROM, nerve gliding
35
Q

Ulnar Nerve Palsy/Ulnar Nerve Lesion

A
  • Deformity is produced by imbalance of the intrinsic and extrinsics.
  • Results in clawing of the ring and small finger

*18% of nerve injuries (claw hand deformity)

  • intrinsic muscles must be markedly weakened or paralyzed to produce claw deformity.
  • long extensor muscles hyperextend the MCP joint, & long flexor muscles flex the PIP and DIP joints. - due to the anatomy of the sagittal band, MP joint hyperextension blocks the central slip from extending the PIP;
36
Q

Ulnar nerve palsy

A
  • hand based to block MY hyperextension

* maintains the transmetacarpal arch

37
Q

muscles affected with wrist level injury of the Ulnar nerve

A
  • Abductor digiti minimi
  • flexor digiti minimi
  • Opponens digiti minimi
  • Lumbricals 4 and 5
  • Dorsal and Palmer Interossei
  • Flexor pollicis brevis deep head
  • adductor pollicis
38
Q

motor loss if there is an ulnar nerve lesion at the elbow

A
  • Flexor carpi ulnaris
  • Flexor digitorum profundus of the ring and small finger
  • plus all the muscles listed on the previous slide
39
Q

Sensation impairment

A
  • Sensation is impaired proximally and dorsally with cubital tunnel
  • Sensation is impaired only on the volar side with entrapment at guyan canal.
40
Q

Median Nerve

A
  • sensation on dorsal aspect as well- tip of thumb, pointer, middle, and part of the ring. And some distal aspects of the forearm.
  • Superficial branch of the radial cutaneous and radial do the other aspects of the dorsal hand and forearm.
41
Q

Common median nerve entrapments

A
  • Carpal Tunnel
  • Pronator Syndrome
  • Anterior Interosseous Syndrome- similar to posterior interosseous syndrome
  • High versus low median nerve injuries.
42
Q

Median nerve function

A
  • The median nerve has the most autonomic/sympathetic fibers in the upper extremity.
  • The Median nerve is vulnerable to injury when there is a distal radius fracture. High incidence of developing complex regional pain syndrome/RSD.
  • 500 mg Vitamin C recommended a day following a fracture of the radius in order to prevent CRPS.
43
Q

Pillar pain

A
  • Pain in the palm- mid aspect of the palm
    1) the nerve may not wake up after surgery
    2) if patient is diagnosed
    3) good relief initially but goes back to typing every day and presents again.
    4) double crush syndrome.
44
Q

Carpal tunnel (compression)

A
  • If mild carpal tunnel procedure- invasive is better (on underside and cannot tell if there are osteocytes, if you cut everything you needed, or they can cut an artery and cause bleeding, cannot tell what the nerve bed looks like.
  • mini open- 2 cm incision in the palm- can see everything, clean it up and make sure it glides easily.
45
Q

Carpal Tunnel Syndrome

A
  • Most common peripheral nerve entrapment

* Median nerve is the softest and most volar structure so it is prone to compression

46
Q

Median nerve injury

A

Types of nerve injury:

  • trauma (laceration, crush, burn), Compression (acute or chronic), stretching (traction), Ischemia, electrical current or late effects of radiation,
  • most common are lacerations (partial or complete)
  • changes in tunnel dimension:
    • cysts, tumors, bone spurs/arthritis

SWELLING!!

47
Q

Carpal Tunnel Syndrome cont’d

A
  • Decreased sensation to light touch the first to decline, hypersensitive, night pain and paresthesia
  • always ask patient about what symptoms are at night.
48
Q

what will patient look like (carpal tunnel)

A
  • numbness and night pain
  • paresthesia (tingling and numbness) in median nerve distribution (sensor, touch, lost first)
  • weakness of pinch 2 pt and 3 pt
  • decreased strength and coordination
  • Thenar atrophy present with long term compression
  • pt. might complain they keep dropping things
  • pt. might complain of pain in their hands.
49
Q

Conservative Treatment

A
  • Wrist neutral splint- nerves like to be straight
  • Night splint (block the MP)
  • Avoid full digit flexion with grip exercises. Grip strengthening contraindicated (can perform blocking, straight fist, hook and intrinsic exercises)
  • avoid repetitive or sustained wrist flexion or extension
  • Avoid pressure over carpal canal
50
Q

treatment of sensory deficits

A
  • educate in compensation techniques
  • Sensory re-education program
  • Desensitization program
51
Q

other treatments

A
  • massage to the palm- soft tissue work to loosen everything up
  • nerve glides flossing
  • Yoga stretching (rolling stretch not sustained for long periods)
52
Q

Mirror Therapy

A

If getting abnormal input we have to try and correct that. Cortical mapping- provide image to the side that is not functioning properly of what it is supposed to do if the patient can buy into it.

53
Q

Pronator Syndrome

A
  • Post-op scar massage, nerve glides
  • Higher up at the level of the pronator- tight forearm muscles (pronator and the FDS), looks very similar to carpal tunnel (EMG doesn’t identify well)
  • Bad if they have to do a lot of rotation- should check on that movement.
54
Q

Pronator Syndrome Cont’d

A

-compression of the nerve between the two heads of the pronator teres.

Symptoms:
-pain/weakness in resisted pronation at the medial proximal forearm

Splint to prevent pronation and supination as well as wrist flexion and extension
-long arm splint elbow splint in forearm neutral and elbow flexed at 90.

55
Q

Pronator Syndrome intervention

A
  • soft tissue mobilization (manual or instrument assisted)
  • Stretch of forearm musculature-free up restriction (gentle progressions)
  • Nerve glides and flossing
56
Q

Anterior Interosseous Syndrome

A
  • Compression as the nerve penetrates the flexor digitorum profundus in the forearm.
  • Supplies function to the FPL, pronator quadratus, FDP to the index finger.
  • Test strength of maintaining the “OK” sign
  • EMG more likely to show AIN than PIN. AIN and PIN are purely motor nerves

Intervention

  • soft tissue mobilization
  • Activity modification
57
Q

Anterior Interosseous Syndrome

A

Symptoms

  • difficulty writing
  • pain (no paraesthesia) in proximal forearm
  • patients cannot perform “OK” finger motion
58
Q

Low Median Nerve Palsy/Ape hand

deformity (laceration of Nerve at wrist level)

A
  • Client’s ability to oppose is weak, and the FPL provides most of the strength in flexion
  • Opposition is attempted but cannot be done because of atrophy of the opponens and APB
  • Thumb abduction strength will decrease on average by 70%
  • Thumb may remain supinated
  • May be some clawing of index and long fingers (lumbricals)
59
Q

Splinting post median nerve damage

A
  • Day splint: C-Bar w/ thumb palmarly abducted

- Night splint: web space in full radial abduction

60
Q

High median nerve palsy (proximal injury)

A
  • Loss of pronation of forearm, wrist flexors, index and long finger flexion, and FPL
  • In addition to distal losses in the hand
  • Train in sensory precautions and re-education
  • Graded motor imagery
61
Q

Radial nerve

A
  • radial nerve injury from midshaft humeral fracture
  • Saturday night palsy
  • radial tunnel
  • Wartensburg syndrome

results in loss of wrist and finger extension.

62
Q

Radial Tunnel Syndrome

A
  • Compression of the posterior interosseous nerve as it divides and pierces the Arcade of Frohse and compression between the supinator and radial head.
  • Sometimes mistaken for tennis elbow
  • can coincide with tennis elbow
  • avoid repetitive supination and pronation, wrist supported in neutral

Symptoms
-tenderness/pain at the radial head and proximal common extensor muscle bellies. Often described as achiness

63
Q

Wartenberg’s Syndrome

A

-Superficial radial cutaneous nerve irritation

Due to:

  • tight cast
  • tight watch bands
  • direct trauma
  • Surgical injury (can get cut during a DeQuervains surgery
  • IV placement-puncture
  • External fixators

*Usually caused by a tight cast- the one that grows thicker hair in sites of the cast.

Pain, tingling, and numbness over the back and side of the hand, index and thumb

(increased pain with writing and gripping and forearm rotation)
*report it more as burning sensation

64
Q

Treatment

A
  • thumb spica
  • Neoprene splint
  • Desensitization
  • Don’t want to stretch and strain it. DeQuervain’s can look like it and the two can coincide with each other because there is swelling in there.
  • Want to start exposing area to different sensations.
65
Q

Proximal Radial Nerve Lacerations

A
  • Long term radial nerve or tenodesis splint.
  • Prevention of joint contractures-night time splinting and PROM to wrist, digits, elbow if high tension.
  • Education in sensory precautions- hot cold, sharp, pressure.
  • Graded motor imagery
  • Maintain strength, ROM, and functional use of unaffected joints.
  • Teach compensatory strategies
  • provide adaptive equipment
  • teach how to do PROM to their own wrist and digits
  • with splint on we can still work on grip.

Musckuloskeletal (14 decks)

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