SM_231a: Peripheral Neuropathies of the Upper Limb Flashcards Preview

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Flashcards in SM_231a: Peripheral Neuropathies of the Upper Limb Deck (57)
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1

Describe general features of neuropathies

Neuropathies

  • Nerves can be damaged by disease (e.g. diabetes), drugs/toxins (e.g. alcohol), or trauma (cutting, compression, or stretching)
  • Disease, drugs, and toxins may affect many nerves at the same time (polyneuropathy) symmetrically on both sides of the body
  • Trauma affects one nerve (mononeuropathy) on one side
  • Nerves can be cut by penetrating wounds or fractures if a nerve contacts a bone, compressed against a bone by a hard object or swelling in an osseofibrous joint, and stretched by dislocation or excessive movement in a joint

2

____, ____, and ____ can cause neuropathies

Disease (e.g. diabetes), drugs/toxins (e.g. alcohol), and trauma (cutting, compression, or stretching) can cause neuropathies

3

Disease, drugs, and toxins affect ____ nerves at the same time ____

Disease, drugs, and toxins affect many nerves at the same time (polyneuropathy) symmetrically on both sides of the body

4

Trauma typically affects _____ on _____

Trauma typically affects one nerve (mononeuropathy) on one side

5

Nerves can be damaged by trauma including ____, ____, and ____

Nerves can be damaged by trauma including cutting, compression, or stretching

6

Injury to a nerve causes muscles and skin supplied by the nerve to lose their innervation, resulting in _____ and _____

Injury to a nerve causes muscles and skin supplied by the nerve to lose their innervation, resulting in paralysis and anesthesia

  • Complete paralysis: no movement is detectable because all muscles producing a movement have lost innervation
  • Incomplete paralysis: not all muscles producing movement have lost innervation -> muscle can move but movement is weak or paretic
  • Anesthesia (numbness): loss of cutaneous sensation tested by pinprick or touch

7

Knowing _____ and _____ is necessary to evaluate neuropathies

Knowing course and distribution is necessary to evaluate neuropathies

  • Course: indicates where nerve has been injured, only muscles and skin areas distal to the site of injury will be affected
  • Distribution (muscles and skin innervated): indicates what muscles and skin have been affected by the injury

8

Upper brachial plexus injuries (Erb-Duchenne / Erb's palsy) result from ______

Upper brachial plexus injuries (Erb-Duchenne / Erb's palsy) result from traction or tear of the upper trunk (C5 and C6)

9

Upper brachial plexus injuries (Erb-Duchenne / Erb's palsy) result from _____ in adults and _____ in newborns

Upper brachial plexus injuries (Erb-Duchenne / Erb's palsy) result from a blow to the shoulder producing excessive separation of the neck and shoulder in adults and pulling of head when arm is caught in birth canal in newborns

10

Injury to the upper brachial plexus (Erb-Duchenne / Erb's palsy) causes _____, resulting in _____

Injury to the upper brachial plexus (Erb-Duchenne / Erb's palsy) causes paralysis of proximal limb muscles (C5, C6 myotomes), resulting in waiter's tip position

11

Describe waiter's tip position

Waiter's tip position

  • Results from injury to upper brachial plexus
  • Paralysis of proximal limb muscles (C5, C6 myotomes)
  • Loss of arm flexion, abduction, and lateral rotation (biceps, deltoid, supraspinatus, infraspinatus, teres minor)
  • Loss of forearm flexion and weakness of supination (biceps, brachialis, brachioradialis)
  • Weakness of wrist extension (wrist extensors innervated in part by C6)
  • Limb hands by side in medial rotation and pronation, hand is flexed

12

Upper brachial plexus injury (Erb-Duchenne / Erb's palsy) results in _____ of the _____ dermatomes on the _____ side of the arm, forearm, and hand

Upper brachial plexus injury (Erb-Duchenne / Erb's palsy) results in anesthesia of the C5-6 dermatomes on the lateral side of the arm, forearm, and hand

13

Lower brachial plexus injuries (Klumpke's palsy) result from _____

Lower brachial plexus injuries (Klumpke's palsy) result from traction or tear of the lower trunk (C8, T1)

14

Lower brachial plexus injuries (Klumpke's palsy) result from _____ in adults and _____ in newborns

Lower brachial plexus injuries (Klumpke's palsy) result from grasping something to break a fall in adults and forceful upward pull of the shoulder during birth by pulling on the arm when the head is caught in the birth canal in newborns

15

Lower brachial plexus injuries (Klumpke's palsy) may cause _____ due to compression of the _____ and _____ against the first rib by a cervical rib

Lower brachial plexus injuries (Klumpke's palsy) may cause thoracic outlet syndrome due to compression of the trunk and subclavian artery against the first rib by a cervical rib

16

Lower brachial plexus injuries (Klumpke's palsy) result in _____, causing _____

Lower brachial plexus injuries (Klumpke's palsy) result in paralysis of distal limb muscles (C8, T1 myotomes) primarily affecting intrinsic hand muscles innervated by median and ulnar nerves, causing Klumpke's total claw hand

17

Lower brachial plexus injuries (Klumpke's palsy) result in _____ in the _____ dermatomes along the _____ side of the arm, forearm, and hand

Lower brachial plexus injuries (Klumpke's palsy) result in anesthesia in the C8 and T1 dermatomes along the medial side of the arm, forearm, and hand

18

Describe Klumpke's total claw hand

Klumpke's total claw hand

  • Caused by lower brachial plexus injuries
  • Paralysis of distal limb muscles (C8, T1) primarily affecting intrinsic hand muscles innervated by the median and ulnar nerves
  • Loss of flexion of MCP joints (interossei, lumbricals)
  • Loss of extension of PIP and DIP joints (lumbricals) in fingers
  • Paralysis of thenar and hypothenar muscles

19

Interossei function to _____ and _____ the fingers and _____ the MCP joints

Interossei function to adduct and abduct the fingers and flex the MCP joints

20

Lumbricals ____ the PIP and DIP joints and assist interossei in ____ the MCP joints

Lumbricals extend the PIP and DIP joints and assist the interossei in flexing the MCP joints

21

In Klumpke's total claw hand, patients cannot ____ the MCP joints or ____ the IP joints

In Klumpke's total claw hand, patients cannot flex the MCP joints or extend the IP joints

 

(unopposed actions of long extensors and flexors pull the MCP joints of all digits into hyperextension and the IP joints into flexion, causing Klumpke's total claw hand)

22

____ can compress or cut the median nerve proximally

Fractures of the supracondylar humerus can compress or cut the median nerve proximally

23

____ is the most common cause of injury to the median nerve distally

Carpal tunnel syndrome is the most common cause of injury to the median nerve distally

 

(produced by repetitive hand and finger movements that lead to swelling of the long flexor tendons and their synovial sheaths, compressing the median nerve)

24

Repetivie hand and finger movements cause carpal tunnel syndrome by promoting ____ of the long flexor tendons and their synovial sheaths, ____ the nerve

Repetivie hand and finger movements cause carpal tunnel syndrome by promoting swelling of the long flexor tendons and their synovial sheaths, compressing the nerve

25

Median nerve innervates _____ and the _____ intrinsic hand muscles

Median nerve innervates all flexor forearm muscles except for the 1.5 innervated by the ulnar nerve and the med. LOAF intrinsic hand muscles

  • med - median nerve
  • L - 1st and 2nd lumbricals
  • O - opponens pollicis
  • A - abductor pollicis brevis
  • F - flexor pollicis brevis (superficial head)

26

Med. LOAF stands for _____, all of which are _____ hand muscles

Med. LOAF stands for median nerve, 1st and 2nd lumbricals, opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis (superficial head)


(innervated by median nerve)

27

_____ lesions of the median nerve produce _____ caused by long of thumb opposition (flexion and abduction) with atrophy of thenar eminence

Proximal and distal lesions of the median nerve produce ape hand caused by long of thumb opposition (flexion and abduction) with atrophy of thenar eminence

 

(thumb remains extended and adducted)

28

Sensory changes caused by injury to median nerve are ____

Sensory changes caused by injury to median nerve are on the dorsal and palmar surfaces of the thumb, index, middle, and lateral half of the ring fingers (lateral 3.5 digits) and adjacent portion of the palm

29

_____ lesions to the median nerve produce _____ when the patient is asked to _____ the fingers

Proximal lesions to the median nerve produce Pope's hand / hand of benediction when the patient is asked to flex the fingers

 

  • Cannot flex digits 2 and 3 (index and middle fingers) due to paralysis of flexor digitorum superficialis and lateral half of flexor digitorum profundus

30

Distal lesions to the median nerve produce _____ 

Distal lesions to the median nerve produce median claw hand of digits 2 and 3

 

  • Unopposed actions of long flexors (flexor digitorum superficialis and lateral half of flexor digitorum profundus) and extensors (extensor digitorum, extensor incisis) pull the MCP joints of the index and middle fingers into extension and the IP joints into flexion

 

 

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