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M2 Musculoskeletal > 4/12 Upper Extremity Injuries - Corbett > Flashcards

4/12 Upper Extremity Injuries - Corbett Flashcards

1
Q

brachial plexus

mnemonic

A

robert taylor drinks cold beer

roots-trunks-divisions-cords-branch

  • roots of spinal nerves
  • trunks in posterior triangle of neck
  • divisions behind clavicle
  • cords in axilla

lateral cord →

  1. musculocutaneous n
  2. lat pectoral n
  3. lat root of median n

medial cord →

  1. medial cutaneous n of arm
  2. medial pectoral n
  3. medial cutaneous n of forearm
  4. medial root of median n
  5. ulnar nerve

posterior cord →

  1. axillary n
  2. upper and lower subscapular nn
  3. thoracodorsal n
  4. radial n
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2
Q
A
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3
Q

long thoracic nerve

A

C5-C7

innervates: serratus ant m

  • stabilizes scapula
  • abduction/overhead use (arms all the way up)

mech of injury:

  • surgical (in axilla)
  • downward traction on scapula
  • chest wall compression

presentation: winged scapula

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4
Q

axillary nerve

A

C5-C6

innervates: deltoid

  • major ABductor at shoulder

innervates: teres minor (clinically irrelevant)

sensory: skin over deltoid

mech of injury: shoulder dislocation (fall with shoulder abducted/externally rotated), fracture of surgical neck of humerus

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5
Q

musculocutaneous nerve

A

C5, C6, C7 (from lateral cord of BP)

  • pierces coracobrachialis…
  • innervates:
    • biceps brachii
    • brachialis
    • coracobrachialis
  • and then continues as lateral cutaneous nerve of arm
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6
Q
A
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7
Q

radial nerve

A

C5-T1

innervates: posterior muscles of arm/forearm

  • extension at elbow
  • extension of wrist/fingers
  • supination of forearm

sensory: posterior arm/forearm, posterior hand (lateral 3.5 digits

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8
Q

mech of radial nerve injury

A
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9
Q

median nerve

A

C5-T1

innervates:

  • (almost all) muscles of forearm​​
  • muscles of thenar eminence
  • 1st, 2nd lumbricals

wrist flexion and abduction, forearm promation, thumb flexion and opposition, flexion of digits 2/3

sensory: palmar surface of hand

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10
Q

median nerve injuries/deficits

A
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11
Q

normal position of thumb

muscles involved

deficiency

A

LOAF

  • abductor pollicis brevis and opponens pollicis keep thumb in slightly ventral and abducted

passive sign - pt not DOING anything to show this sign

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12
Q

sign of benediction

A

active sign - need to ask pts to make a fist

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13
Q

proximal median nerve injury

vs

distal median nerve injury

A

sign of benediction (active sign)

vs

median clawing (passive sign)

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14
Q

mechanisms of median nerve injury

A
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15
Q

carpal tunnel syndrome

A

palmar branch of median nerve comes OFF BEFORE carpal tunnel!!!

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16
Q

ulnar nerve

A

C8-T1 (from medial cord)

  • no branches in axilla, arm
  • passes behind medial epicondyle to enter forearm

innervates: 1.5 muscles in forearm

  • flexor carpi ulnaris → wrist flexion on ulnar side
  • flexor digitorum profundus → flexion of distal phalanx of digits 4/5

most of the stuff in teh hand:

  • hypothenar muscles
  • meial two lumbricals
  • adductor policis
  • all interossei

sensory__:

  • dorsal cutaneous branch
  • palmar cutaneous branch
17
Q

claw hand

A
18
Q

Froment sign

A

ulnar nerve injury

hyperflexion of thumb when making a-ok pinch sign

loss of ulnar-adductor pollicis = reliance on flexor pollicis longus and exaggerated IP joint flexion

19
Q

ulnar injuries

A

claw hand

  • paralysis of hypothenar and interosseus muscles
  • loss of adductor policis and medial 2 lumbricals
  • see:
    • hyperext of MCP jts
    • flexion of IP joints (obv in 4th, 5th digits)
    • inability to abduct or adduct the fingers
20
Q

“ulnar paradox”

A

proximal ulnar nerve injury = “not as bad” claw hand

  • hyperextension at MCP joints
  • flexion of IP joints (bc FDS still intact → not as bad as it would be if FDP was lost too)
  • loss of abduction and adduction
21
Q

hamate

A

hook of hamate can fracture if palm hits a surface → damage to deep branch of ulnar n

  • wasting of adductor pollicis, 1st dorsal interossei
22
Q

review images

A
23
Q

upper brachial plexus injury

lower brachial plexus injury

A

upper → “Erb-Duchenne palsy” → “waiter’s tip”

lower → “clawhand”

24
Q

Erb Duchenne palsy

A

upper BP injury

results from excessive displacement of head to opposite side/depression of shoulder on same side

(i. e. formation of an obtuse angle between head/shoulder)
ex. labor, surgical positioning, fall

affects C5/C6 roots of superior trunk (see pic)

**link to Horner syndrome bc sympathetic trunk runs close

25
Q

Klumpke palsy

A

lower lesion of brachial plexus

usually traction injury due to excessive abduction of arm

(i.e. catching yourself to break a fall, pulling arm during labor)

injures: first thoracic nerve → affects ulnar and median nerve in supply all small muscles of hand

  • clawed appearance due to hyperext of MCP joints, flexion of IP joints

M2 Musculoskeletal (21 decks)

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