Brachial Plexus Flashcards
1
Q
Spinal cord length
A
C1-L2
2
Q
Number of spinal cord segments
A
31 segments 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
3
Q
Segments give rise to
A
rootlets –> roots –> pair of spinal nerves –> multiple spinal nerves= regional plexus
4
Q
7 cervical vertebrae but
A
8 cervical spinal nerves
5
Q
C1-C7 exit…
A
above the spinal vertebra
6
Q
Nerves are very mixed
A
Most nerves contain many types of motor and sensory fibers
7
Q
Motor fibers go to
A
voluntary muscles
involuntary muscles
glands
vessels
8
Q
Sensory fibers go to
A
general sensory fibers
proprioceptor fibers
visceral afferents
9
Q
Spinal nerves split into
A
dorsal and ventral rami
10
Q
Sensory
A
Dorsal rootlets
Dorsal root
Dorsal root ganglion
11
Q
Motor
A
Ventral rootlets
Ventral root
12
Q
Spinal nerve
A
Dorsal ramus
Ventral ramus
13
Q
Brachial Plexus formed by
A
ventral roots of C5-T1
14
Q
Brachial Plexus divisions
A
Roots Trunks Divisions Cords Branches
15
Q
Roots
A
Five
C5-T1
(a.k.a. ventral rami)
16
Q
Trunks
A
Three
Upper, middle and lower
17
Q
Divisions
A
Six
Anterior and posterior
18
Q
Cords
A
Three
Medial, lateral, posterior
19
Q
Branches
A
Five Major: Axillary Musculocutaneous Median Ulnar Radial
20
Q
Dorsal and ventral roots (rootlets)
A
Contains either sensory or motor fibers
Dorsal= Sensory, Ventral= Motor
21
Q
Spinal nerve
A
Mixed with both motor and sensory fibers
22
Q
Ventral ramus
A
What we care about
23
Q
Dorsal ramus
A
tiny insignificant branches to muscles and skin of the back
24
Q
Scalene muscles in the neck
A
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
