Brachial Plexus Flashcards Preview

Term 1 Anatomy > Brachial Plexus > Flashcards

Flashcards in Brachial Plexus Deck (87):
1

Spinal cord length

C1-L2

2

Number of spinal cord segments

31 segments
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

3

Segments give rise to

rootlets --> roots --> pair of spinal nerves --> multiple spinal nerves= regional plexus

4

7 cervical vertebrae but

8 cervical spinal nerves

5

C1-C7 exit...

above the spinal vertebra

6

Nerves are very mixed

Most nerves contain many types of motor and sensory fibers

7

Motor fibers go to

voluntary muscles
involuntary muscles
glands
vessels

8

Sensory fibers go to

general sensory fibers
proprioceptor fibers
visceral afferents

9

Spinal nerves split into

dorsal and ventral rami

10

Sensory

Dorsal rootlets
Dorsal root
Dorsal root ganglion

11

Motor

Ventral rootlets
Ventral root

12

Spinal nerve

Dorsal ramus
Ventral ramus

13

Brachial Plexus formed by

ventral roots of C5-T1

14

Brachial Plexus divisions

Roots
Trunks
Divisions
Cords
Branches

15

Roots

Five
C5-T1
(a.k.a. ventral rami)

16

Trunks

Three
Upper, middle and lower

17

Divisions

Six
Anterior and posterior

18

Cords

Three
Medial, lateral, posterior

19

Branches

Five Major:
Axillary
Musculocutaneous
Median
Ulnar
Radial

20

Dorsal and ventral roots (rootlets)

Contains either sensory or motor fibers
(Dorsal= Sensory, Ventral= Motor)

21

Spinal nerve

Mixed with both motor and sensory fibers

22

Ventral ramus

What we care about

23

Dorsal ramus

tiny insignificant branches to muscles and skin of the back

24

Scalene muscles in the neck

BP roots travels between anterior and middle scalene muscles

25

Clavicle

BP trunk/divisions travel under it

26

Axillary artery

BP cords wrap around it

27

Axilla

BP becomes 5 major terminal branches and send many smaller nerve branches

28

Scalene muscles

Anterior, middle, posterior arise from the transverse process of Rib 1 anterior and middle
Rib 2 posterior

29

Roots, trunks, divisions are

all in the neck region ABOVE or under the clavicle

30

Only the cord region and terminal branches are

visible in the axilla, distal to clavicle

31

Phrenic nerve

C5 root
branches off before BP cords

32

Long thoracic nerve

C5, 6, 7 root (serratus anterior)
branches off before BP cords

33

Dorsal scapular nerve

C5 root (rhomboids, levator scapulae)
branches off before BP cords

34

Suprascapular nerve

C5, 6 superior trunk (supra. and infraspinatus)

35

Nerve to subclavius

C5, 6 superior trunk

36

Posterior cord

Formed by posterior divisions of all three trunks (C5-T1)
Supplies muscles in the posterior compartments of the arm and forearm
Extensors
Travel posterior (behind) axillary artery

37

Posterior cord nerve branches

Radial nerve
Axillary nerve
Thoracodorsal nerve
Upper subscapular nerve
Lower subscapular nerve

38

Radial nerve

(C5-T1)
Dives through tricepts hiatus (triagular interval) with profunda brachial artery
Supplies extensor compartments of upper extremity

39

Axillary nerve

(C5, C6)
Dives through quadrangular space with posterior humeral circumflex artery
Supplies deltoid and teres minor

40

Thoracodorsal nerve

(C6, 7, 8) a.k.a middle subscapular nerve
Supplies latissimus dorsi

41

Upper subscapular nerve

(C5, 6)
Supplies subscapularis

42

Lower subscapular nerve

(C5, 6)
Supplies teres major

43

Medial cord

Formed by anterior divisions of lower trunk
(C8, T1)

44

Medial cord nerve branches

Ulnar nerve
Medial pectoral nerve
Medial cutaneous nerves of arm and forearm
Gives contribution to median nerve

45

Ulnar nerve

(C8, T1)
Passes posterior to medial epicondyle
Nerve for your hand

46

Medial pectoral nerve

Supplies pectoralis major and minor

47

Medial cutaneous nerves of arm and forearm

medial arm/forearm sensation

48

Lateral cord

Formed by anterior divisions of upper and middle trunks (C5, 6, 7)

49

Lateral cord nerve branches

Musculocutaneous nerve
Lateral pectoral nerve
Lateral contribution to median nerve

50

Musculocutaneous nerve

Dives through coracobrachialis
Supplies flexor compartment of arm (corachobrachialis, biceps brachii, and brachialis)

51

Lateral pectoral nerve

Supplies pectoralis major

52

Median nerve

Formed by contributions from median and lateral cords (C6-T1)

Passes through arm with brachial artery

Controls anterior forearm muscles, hand muscles a little bit

53

Axillary roots

C5, C6

54

Musculocutaneous roots

C5, C6, C7

55

Ulnar roots

C8, T1

56

Median roots

C5, C6, C7
C8, T1

57

Radial roots

C5, C6, C7, C8, T1

58

Dermatome

An area of skin whose nerve supply is derived from the same spinal cord segment

59

Thumb and half index dermatome
Lateral forearm

C6

60

Middle finger dermatome

C7

61

Pinky and half of ring dermatome
Medial forearm

C8

62

Lateral arm

C5

63

Medial arm (bottom half)

T1

64

Lateral shoulder/arm

Axillary
Cutaneous branch of axillary nerve
Superior lateral cutaneous branch of axillary nerve

65

Lateral forearm

Lateral cutaneous nerve of forearm

66

Lateral thumb

Superficial branch of radial

67

Middle finger index finger

Median

68

Pinky

Ulnar

69

Medial forearm

Medial cutaneous nerve of forearm

70

Medial arm

Medial cutaneous nerve of arm

71

Hand

T1 myotome

72

Wrist

C8 myotome

73

Forearm

C7 myotome

74

Antecubital region

C6 myotome

75

Arm

C5 myotome

76

Triceps tendon reflex

C7

77

Biceps tendon reflex

C6

78

Erbs Palsy

Superior brachial plexus injury

Avulsion of upper roots of brachial plexus
C5, 6

79

Loss of fibers to suprascapular nerve

results in medial rotation of shoulder

80

Loss of fibers to axillary nerve

results in deltoid atrophy

81

Loss of fibers to musculocutaneous

results in extension of the elbow and pronation of radioulnar joint

82

Waiter's tip

Erb's palsy
Characteristic position of the limb
Internal rotation of humerus

83

Backpacker's palsy

heavy backpacks may injure superior BP

84

Klumpke's Paralysis

inferior BP injury

avulsion of lower roots of BP
C8, T1

85

Loss of function to the median nerve

results in loss to intrinsic muscle of the thumb

86

Loss of function to the ulnar nerve

results in loss to intrinsic muscles of the hand and inability to extend the interphalangeal joints

87

Claw hand

Klumpke's paralysis
Characteristic position of the hand
Eventual thenar atrophy