Nerves of the Upper Limb Flashcards

1
Q

what innervation does the brachial plexus supply

A

somatomotor and somatosensory innervation to the upper extremity

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2
Q

what does the brachial plexus arise from

A

the cervical enlargement of the spinal cord

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3
Q

what section of the spinal cord gives rise to the brachial plexus

A

ventral (anterior) rami of cervical spinal nerve roots C5-T1

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4
Q

where do spinal nerve roots supplying the brachial plexus emerge from and what do they pass through

A

intervertebral formaina of cervical vertebrae and pass between the anterior and middle scalene muscles (interscalene space) of the neck

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5
Q

where does the brachial plexus emerge

A

posterolateral to the sternoclediomastoid muscle in the lateral neck region in the posterior triangle through the interscalene space at the level of the cricoid cartilage of the larynx

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6
Q

the brachial plexus maintains an anatomical relationship with subclavian artery and vein as it travels where

A

posterior to the omohyoid muscle and the clavicle on its way to the axilla

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7
Q

what is an interscalene block used for

A

anesthesia of the brachial plexus to temporarily block sensation and motor function to the upper limb

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8
Q

what is a common complication of interscalene blocks

A

accidental partial anesthesia of the diaphragm and temporary respiratory depression due to the proximity of phrenic nerve (C3-C5) to the anterior scalene muscle and compartmentalization of fascia within the neck

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9
Q

what portion of the spinal cord does the phrenic nerve and the brachial plexus overalp

A

C5

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10
Q

when doing an interscalene block what anatomical relationships must you have knowledge of

A

posterior triangle of the neck

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11
Q

what does the brachial plexus pass as it enters the axillary region

A

travels posterior to the pectoralis minor where it forms a relationship with the axillary artery such that the artery runs in the middle of the plexus and is surrounded by the cords and terminal branches

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12
Q

what is the axillary vein’s relationship with the brachial plexus

A

the axillary vein and its tributaries entangle themselves with the branches of the brachial plexus

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13
Q

as the brachial plexus runs into the axilla and along the axillary artery and vein what is it surrounded in

A

surrounded in a neurovascular bundle by the axillary sheath

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14
Q

what does the axillary sheath contain

A

axillary vein, axillary artery, brachial plexus

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15
Q

what are the features of the brachial plexus

A

lateral cord, medial cord, and posterior cord

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16
Q

what is a dermatome

A

area of cutaneous sensory innervation supplied by a single spinal nerve

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17
Q

what dermatomes does C4 supply

A

supraclavicular and upper shoulder region

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18
Q

what dermatomes does C5 supply

A

upper lateral arm and shoulder

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19
Q

what dermatomes does C6 supply

A

posteriolateral arm and lateral forearm

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20
Q

what dermatomes does C7 supply

A

middle of forearm and hand

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21
Q

what dermatomes does C8 supply

A

posteriomedial forearm and medial hand

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22
Q

what dermatomes does T1 supply

A

medial arm

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23
Q

what dermatomes does T2-T5 supply

A

axillary region

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24
Q

what spinal nerves do T2-T5 respond to

A

intercostal nerves

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25
Q

what spinal nerve does T1 respond to

A

medial antebrachial cutaneous nerve and medial brachial cutaneous nerve

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26
Q

what nerve does C8 respond to

A

ulnar nerve

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27
Q

what nerve does C7 respond to

A

median nerve

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28
Q

what nerves does C6 respond to

A

median nerve, radial nerve, and musculocutaneous nerve

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29
Q

what nerve does C5 respond to

A

superior lateral brachial cutaneous nerve (axillary nerve)

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30
Q

what nerve does C4 respond to

A

superior lateral brachial cutaneous nerve (axillary nerve) and supraclavicular nerves

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31
Q

how many spinal nerves supply an individual named muscle in the limbs

A

more than one

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32
Q

what is a myotome

A

a group of muscles that receive motor innervation from a single spinal nerve

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33
Q

what are the divisions of the trunks of the brachial plexus

A

anterior and posterior division

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34
Q

what do the divisions of the trunks of the brachial plexus contribute to

A

branches that correspond to anterior parts of the limb or posterior parts of the limb

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35
Q

what muscles are in the anterior compartment of the upper extremity

A

biceps and brachialis

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36
Q

what nerve innervates the muscles in the anterior compartment of the upper extremity

A

musculocutaneous nerve

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37
Q

what muscle in is the posterior compartment of the upper extremity

A

triceps

38
Q

what nerve innervates the three heads of the triceps in the posterior compartment of the upper extremity

A

the radial nerve

39
Q

what is the function of anterior muscles in the upper extremity

A

flexion of elbow joint

40
Q

what is the function of posterior muscles in the upper extremity

A

extension of elbow joint

41
Q

what divides the anterior and posterior compartments of the upper extremity

A

medial and lateral intermuscular septa

42
Q

what divides the anterior and posterior compartments of the forearm

A

interosseous membrane

43
Q

in the upper arm and forearm what portion of the spinal nerves contribute to the anterior compartment? posterior compartment?

A

anterior: only anterior division contributions from spinal nerves
posterior: only posterior division contributions from spinal nerves

44
Q

what nerves run in the anterior compartment of the forearm

A

ulnar and median nerves

45
Q

what nerves run in the posterior compartment of the forearm

A

radial nerve

46
Q

what is the shoulder (pectoral girdle) region innervated by

A

nerves that come directly from the roots, trunks, or cords of the brachial plexus

47
Q

what is the arm (brachial) region innervated by

A

nerves from the medial cord (cutaneous), the musculocutaneous nerve (anterior) and the radial nerve (posterior)

48
Q

what is the forearm (antebrachial) region innervated by

A

a branch from the medial cord (cutaneous), the median and ulnar nerves (anterior) and the radial nerve (posterior)

49
Q

what motor innervation does the hand receive

A

from the median and ulnar nerves

50
Q

what sensory innervation does the hand receive

A

median, ulnar and radial nerves

51
Q

What levels of the spinal cord does the musculocutaneous nerve receive innervation from

A

C5-C7

52
Q

what levels of the spinal cord does the median nerve receive innervation from

A

C5-T1

53
Q

what levels of the spinal cord does the ulnar nerve receive innervation from

A

C8-T1

54
Q

what levels of the spinal cord does the radial nerve receive innervation from

A

C5-T1

55
Q

what levels of the spinal cord does the axillary nerve receive innervation from

A

C5-C6

56
Q

what parts of the brachial plexus are in the surpaclavicular region

A

roots (rami) and trunks

57
Q

what parts of the brachial plexus are in the infraclavicular region

A

divisions, cords, and branches (nerves)

58
Q

what 2 nerves are associated with spinal nerve roots

A

dorsal scapular off C5 and long thoracic off C5-C7

59
Q

what nerve branches off the superior trunk

A

nerve to subclavius and suprascapular nerve

60
Q

what 7 nerves come off of the cords

A

-upper and lower subscapular nerves
-medial pectoral nerve
-medial branchial cutaneous nerve
-medial antebrachial cutaneous nerve
-thoracodorsal nerve
- lacteral pectoral nere

61
Q

what is the nmeuomic to remember the brachial plexus

A

Real Texans Drink Cold Beer

62
Q

how many spinal nerve roots are in the brachial plexus

A

5

63
Q

how many trunks are in the brachial plexus

A

3

64
Q

how many cords are in the brachial plexus

A

3

65
Q

how many terminal branches are in the brachial plexus

A

5

66
Q

what is a common injury to the superior trunk C5 and C6

A

Erb’s palsy

67
Q

what does Erb’s palsy result from

A

excessive, forceful increase in angle between neck and shoulder

68
Q

what is the most common obstetric brachial plexopathy

A

Erb’s palsy

69
Q

what is the clinical presentation of Erb’s palsy

A
  • arm will be adducted
  • arm will be internally (medially) rotated at the elbow
  • there will be pronation
  • there will be extension
70
Q

what is the position of the upper limb described as in Erb’s palsy

A

waiter’s tip

71
Q

what is the spinal nerve root contribution to the superior trunk

A

C5 and C6

72
Q

what is the spinal nerve root contribution to the middle trunk

A

C7

73
Q

what is the spinal nerve root contribution to the inferior trunk

A

C8 and T1

74
Q

what is the spinal nerve root contribution to the axillary nerve

A

C5 and C6

75
Q

what is the spinal nerve root contribution to the radial nerve

A

C5- T1

76
Q

what is the spinal nerve root contribution to the ulnar nerve

A

C7- T1

77
Q

what is the spinal nerve root contribution to the medial nerve

A

C5-T1

78
Q

what is the spinal nerve root contribution to the musculocutaneous nerve

A

C5- C7

79
Q

what muscles present weakness in axillary nerve deficit

A

deltoid and teres minor

80
Q

what muscles present weakness in suprascapular nerve deficit

A

supraspinatus and infraspinatus

81
Q

what muscles present weakness in musculocutaneous nerve deficit

A

biceps

82
Q

what muscles present weakness in radial nerve deficit

A

brachioradialis and supinator and wrist extensors

83
Q

what nerve can be compressed and injured with the use of crutches

A

axillary

84
Q

what is the clinical presentation of injury to the axillary region of the radial nerve

A

weakness when trying to push something away with arm, difficulty extending the wrist, difficulty extending the fingers and opening the hand
-“wrist drop” posture

85
Q

what are the causes of injury of the radial nerve at the spiral groove of humerus

A

-compression of the radial nerve along the midshaft of the humerus “sleep palsy” or “saturday night palsy”
- humeral fracture at midshaft (spiral groove fracture)

86
Q

what is the clinical presentation of injury to the radial nerve at the spiral groove of humerus

A

-difficulty extending the writst
-difficulty extending or straightening the fingers and opening the hand
-triceps retains strength because nerve fibers entering this muscle branch off proximal to the mid shaft of the humerus
- “wrist drop” posture

87
Q

what are the causes of injury to the axillary nerve

A

-fracture to surgical neck of humerus
-anterior dislocation of glenohumeral joint
- rotator cuff repair surgery

88
Q

what is the clinical presentation of injury to the axillary nerve

A

-numbness in posterior deltoid region
-difficulty abducting arm
- diminished lateral rotation of arm
- deltoid muscle wasting

89
Q

what does the long thoracic nerve innervate

A

serratus anterior muscles

90
Q

what are the causes of injury to the long thoracic nerves

A

-penetrating wound to the axillary region
-surgical removal of axillary lymph nodes

91
Q

what is the clinical presentation of injury to the long thoracic nerve

A

-cannot raise arms above 90 degrees
-“winged scapula”

92
Q

what is the spinal cord level of the long thoracic nerve

A

C5-C7