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Millers > Hand 1 > Flashcards

Hand 1 Flashcards

1
Q

Order from inner to outer
Myelin
Perineurium
Endoneurium
Fascicles
Epineurium
Axon

A

Axon
Myelin
Endoneurium around individual axons
Fascicle = group of axons
Perineurium around fascicle
Epineurium around group of fascicles

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2
Q

What cells make myelin

A

Schwann cells

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3
Q

What is the intrinsic vs extrinsic BS to nerves

A

Intrinsic: plexus within loose connective tissue / epineurium
Extrinsic : vasa nervosum

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4
Q

How do APs move between areas of myelin? What are these areas called?

A

Nodes of Ranvier
Saltatory conduction here

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5
Q

How care for the following nerve injuries:
Laceration
Open wound w/ nerve rupture
Closed injuries

A

Laceration = fix ASAP to avoid fibrosis/retraction
Open wound w/ nerve rupture = allow demarcation (2-3wks) so you can resect all dead tissue for a healthy wound bed at time of repair
Closed injuries = watch 3-6mo recovery

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6
Q

Define following terms and recovery time
Neurapraxia
Axonotmesis
Neurotmesis

A

Neurapraxia - axonal level nerve block
Conduction block, architecture preserved
<3mo

Axonotmesis - discontinuity of axons
Surrounding nerve tube acts as a guide to allow nerve to grow in the right direction
1mm/day

Neurotmesis - complete disruption of entire nerve
Requires surgical intervention

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7
Q

What are the EMG findings for the following
Neurapraxia
Axonotmesis
Neurotmesis

A

Neurapraxia
- Normal insertional activity
- No spont activity

Axonotmesis and neurotmesis hard to differentiate on EMG
- Increased insertional activity
- Fib/positive sharp waves spont activity

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8
Q

What are the best options for nerve repair in the given circumstances:
No tension
<2-3cm gap in sensory nerve
<5cm defect
>5cm defect

A

No tension - direct repair!
= epineurium repair (not fascicle repair bc more scarring)
- Max 10% stretch

<2-3cm gap in sensory nerve - conduit

GRAFT
<5cm defect - allograft but only for sensory n
>5cm defect or any motor involvement - autograft

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9
Q

What are your options for a digital nerve defect?

A

SENSORY only!!!
Primary repair
<3cm = conduit
>3cm = allograft of autograft
Autograft of choice is MABC > LABC

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10
Q

What is the double Oberlin transfer? What is it done for?

A

Gain elbow flexion (feeding goal)
Ulnar n from FCU
Median n from FDS/FCR
To motor br biceps/brachialis

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11
Q

What does EMG vs NCS measure?

A

EMG: electrical activity of muscle w/ voluntary contraction

NCS: nerve conduction velocity, latency, amplitude

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12
Q

NCS
- What happens w/ axonal loss
- What happens w/ demyelination

A

Axonal loss: drop amplitude
- Still conducting, just not as strong

Demyelination: drop velocity -> increase latency

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13
Q

What is most common cause of CTS

A

Edema / vascular sclerosis
Reduced epineurial blood flow
Splinting keeps pressure at neutral to keep blood flow constant

In theory a CSI should work for CTS bc not inflammatory

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14
Q

What are the 2 ways to test sensory nerves? Examples of each

A

Threshold test = measures 1 nerve fiber innervating a receptor. Best for eval nerve after repair
- Static vs moving 2 pt discrimination

Innervation density test = multiple overlapping receptive fields. Best for gradual nerve changes (compressive neuropathy)
- Semmes Weinstein monofilament
- Vibration tests

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15
Q

What are the best provocative tests for CTS

A

Direct compression > Phalen > Tinel

Semmes Weinstein (density test) > 2 pt discrim (threshold)

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16
Q

Findings on EMG for CTS

A

Distal motor latencies > 4.5 msec
Sensory latencies > 3.5 msec

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17
Q

Benefit of endoscopic > open CTR

A

Endoscopic = open long term

Quicker return to work (less incisional/pillar pain early)

Cons: $$, higher risk complication

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18
Q

4 sites of median nerve compression (not CTS)

A

Ligament of struthers = supracondylar process humerus (get an XR)
Lacertus fibrosis (aka biceps aponeurosis)
Deep head pronator (medial epicondyle/deep volar forearm) - why pronator syndrome often associated with medial epicondylitis
FDS arcade

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19
Q

How do you determine a proximal compressive median neuropathy vs CTS

A

Proximal compression you’ll have the sensory br median nerve involved (palm numbness)

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20
Q

AIN syndrome
- Sx
- Muscles innervated
- Causes
- Trt

A

Sx: forearm pain, inability to make O sign index/thumb

Different than other median compressive neuropathy bc motor involvement
- FPL
- FDP index/long
- PQ

Causes:
- Compression by FDS/FCR/PT/FPL
- Parsonage Turner (viral)
- Ddx = tendon rupture (think RA)

Trt: obs obs obs obs

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21
Q

Name the sites of ulnar nerve compression at cubital tunnel

A

Tunnel itself = osborne’s ligament
Arcade struthers = fascia as nerve passes from ant to post in the arm
Medial triceps
Medial IM septum
FCU
Deep flexor/pronator
Anconeus

22
Q

What is Wartenberg sign

A

Lose adductor interosseous of 5th digit
Unopposed EDM (radial n.)
abducted small finger
Ulnar n palsy

23
Q

What is Froment sign

A

Weak thumb adduction - compensatory FPL flexion during pinch
Ulnar n palsy

24
Q

What are the 3 zones of ulnar n compression a Guyons canal + cause

A

1 = proximal to nerve bifurcation = sens + motor
- Ganglion

2 = motor only
- Hook hamate frx

3 = sensory only
- Ulnar art thrombosis

**Dorsal sensory br comes off proximal to the wrist so would not be involved in a Guyon issue

25
Q

What is the anatomy of Guyon tunnel

A

Roof = volar carpal lig
Floor = transverse carpal lig
Radial = hamate
Ulnar = pisiform

26
Q

What are sites of radial n compression (FLEAS)

A

Fascial band radial head
Leash of Henry
ECRB
Arcade Froshe (proximal supinator)
Supinator distal

27
Q

Presentation of PIN syndrome, which patients, trt

A

Motor deficit
- Extending MP joints, thumb IP
- Wrist extension w/ radial dev (ECU out, ECRL intact)

Think RA w/ boggy capsule off radio-capitellar jt

Trt non op as long as not a space occupying lesion

28
Q

Sx radial tunnel syndrome
Most likely compression site
Trt

A

No motor/sens deficit - EMG/NCS normal
Pain syndrome

Arcade of Froshe most common
Think lateral epicondylitis

Nonop

29
Q

Presentation of radial sens n compression
Cause
Trt

A

Forearm pain
+Tinel between BR/ECRL tendon

Direct trauma - tight handcuffs/watch

Diagnostic inj - remove offending agent

30
Q

What is the Adson test for?

A

Thoracic outlet syndrome
Decrease radial a pulse w/ inhalation bc subclavian compression

31
Q

Which nerves create the upper middle lower trunks

A

C5/6 - upper
C7 - middle
C8/T1 - lower

32
Q

How do the trunks divide to make divisons

A

top 2 ant divisions combine = lateral cord
Lower ant div continues own own = medial cord
All 3 posterior divisions combine into 1 = posterior cord

33
Q

What are the 2 branches off C5?

A

Dorsal scapular
Phrenic

34
Q

What nerve roots contribute to long thoracic n?

A

C5/6/7

35
Q

Where does suprascap nerve come from?

A

Upper trunk (C5/6)

36
Q

Name branches off the
Lateral cord (1)
Posterior cord (3)
Medial cord (3)

A

Lateral cord (1)
- Lateral pec

Posterior cord (3)
- Upper, middle, lower subscap

Medial cord (3)
- Medial pec
- Medial brachal
- MABC

37
Q

What are the 5 terminal branches and the cranial nerve contributions

A

MCN - C5/6/7
Ax - C5/6
Rad - C5-T1 (all)
Med - C5-T1 (all)
Ulnar - C7-T1 (low plexus)

38
Q

What nerve roots indicate Horners syndrome

A

C8-T1 avulsion

39
Q

What is the Smith 3-5-7 rule for donor tendon transfer selection

A

Estimates excursion:
Wrist flexors/extensors 3cm
MCP extensors 5cm
FDP 7cm

40
Q

What differentiates a radial nerve injury from PIN?

A

Radial nerve will involve BR and ECRL

41
Q

What are 3 transfers for radial nerve out

A

FCR -> EDC
PL -> EPL
PT -> ECRB

42
Q

What are 2 transfers for median nerve out to regain opposition

A

PL -> thumb prox phalanx
Think elderly severe CTS

ADM -> thumb prox phalanx
Think congenital absence

43
Q

Trt subungal hematoma w/ intact nail plate

A

Nail plate perforation for pain relief

44
Q

How much nail bed must be intact to prevent a hook nail

A

At least 50% of distal phalanx must be there as a bony support to the nail bed

45
Q

Treat finger tip pulp loss up to 1cm

A

2ary intention
FT skin graft 2nd choice

46
Q

Treat finger tip volar oblique injury with exposed bone

A

Adult: cross finger
Kid/younger: moberg (thumb) flap
- Do this in the young bc more likely to overcome any IP contracture

47
Q

Treat finger tip dorsal oblique or transverse injury w/ exposed bone

A

V-Y advancement

48
Q

Treat volar thumb fingertip injury with exposed bone

A

<2cm = moberg volar thumb advancement
>2cm = FDMA (from dorsal 1st digit)

49
Q

Treat dorsal thumb fingertip injury with exposed bone

A

FDMA

50
Q

What is a complication of shortening and closing fingertip injuries

A

Lumbrical plus finger

51
Q

Order the following from which recovers first to last after nerve injury
Motor
Sympathetic
Proprioception
Pain
Temp

A

Return (lose in the opposite order)
1 sympa
2 pain
3 temp
4 proprioception
5 motor

Millers (29 decks)

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