Brachial Plexus Flashcards
1
Q
What roots form the middle trunk of the brachial plexus?
A
C7
2
Q
What roots form the inferior trunk of the brachial plexus?
A
C8 and T1
3
Q
Each trunk of the brachial plexus splits into what structures?
A
Anterior and posterior divisions
4
Q
The three trunks of the brachial plexus pass over what structure going into the axilla?
A
The first rib
5
Q
What do the anterior divisions of the brachial plexus supply?
A
Anterior compartments of the arm and forearm
6
Q
What do the posterior divisions of the brachial plexus supply?
A
Posterior compartments of the arm and forearm
7
Q
What roots make up the brachial plexus?
A
Anterior primary rami of C5-T1
8
Q
What does the brachial plexus supply?
A
Upper extremities
9
Q
In what direction does the brachial plexus travel?
A
Medial to lateral (over first rib into the axilla)
10
Q
Brachial plexus roots combine to form what structures?
A
Trunks
11
Q
Trunks of the brachial plexus divide into what structures?
A
Divisions
12
Q
Divisions of the brachial plexus combine to form what structures?
A
Cords
13
Q
Cords of the brachial plexus divide into what structures?
A
Terminal nerves
14
Q
Dorsal scapular nerve carries fibers from what root?
A
C5 only
15
Q
What muscles are supplied but the dorsal scapular nerve?
A
Rhomboid major and minor, levator scapulae
16
Q
Each root of the brachial plexus receives a gray ramus communicans from what location?
A
Sympathetic trunk
17
Q
The roots of the brachial plexus pass between what two muscles into what body triangle?
A
Between anterior and middle scalene; into posterior triangle
18
Q
Where is the brachial plexus in relation to the subclavian artery?
A
Posterior and superior
19
Q
What divisions form the lateral cord of the brachial plexus?
A
Anterior divisions of the superior and middle trunks
20
Q
What fibers make up the lateral cord of the brachial plexus?
A
C5, C6, and C7
21
Q
The cords of the brachial plexus are named for their relationship to what structure?
A
Axillary artery
22
Q
What is the position of the lateral cord in relation to the axillary artery?
A
Lies lateral to the second part of it
23
Q
Which two nerves are formed from roots of the brachial plexus before they combine to form trunks?
A
Dorsal scapular nerve, long thoracic nerve
24
Q
What does the long thoracic nerve supply?
A
Serratus anterior muscle
25
What divisions form the medial cord of the brachial plexus?
Anterior division of the inferior trunk
26
What fibers make up the medial cord of the brachial plexus?
C8 and T1
27
Where does the medial cord of the brachial plexus lie in reference to the axillary artery?
Medial to the second part of it
28
What divisions form the posterior cord of the brachial plexus?
Union of the posterior division of all three trunks
29
What fibers make up the posterior cord of the brachial plexus?
C5, C6, C7, C8, and T1
30
Where does the posterior cord of the brachial plexus lie in reference to the axillary artery?
Posterior to the second part of it
31
Levator scapulae and the rhomboids all attach to what part of what bone?
Medial border of the scapula
32
Levator scapulae muscles also receive fibers from what roots other than C5?
C3 and C4
33
What nerves branch off of the superior trunk of the brachial plexus?
Suprascapular nerve and nerve to the subclavius
34
What muscles are supplied by the suprascapular nerve?
Supraspinatus and infraspinatus muscles
35
Suprascapular nerve is formed from what fibers of the brachial plexus?
C5 and C6
36
What do the supraspinatus and infraspinatus muscles have in common?
Both rotator cuff muscles, both originate on the posterior (superficial) surface of the scapula
37
Nerve to the subclavius contains fibers from what roots of the brachial plexus?
C5 and C6
38
Nerve to the subclavius supplies what muscle?
Subclavius
39
What nerves make up the supraclavicular portion of the brachial plexus?
Suprascapular, dorsal scapular, long thoracic, and nerve to subclavius
40
What roots form the superior trunk of the brachial plexus?
C5 and C6
41
The long thoracic nerve contains fibers from what roots?
C5, C6, C7
42
What nerves branch off of the lateral cord of the brachial plexus?
Lateral pectoral nerve, musculocutaneous nerve, contribution to the median nerve
43
The lateral pectoral nerve contains fibers from what roots of the brachial plexus?
C5, C6, C7
44
What muscle is supplied by the lateral pectoral nerve?
Pectoralis major
45
What is the pectoralis major muscle's complete nerve supply?
Both the lateral and medial pectoral nerves
46
The musculocutaneous nerve contains fibers from what brachial plexus roots?
C5, C6, C7
47
What muscles are supplied by the musculocutaneous nerve?
Coracobrachialis, biceps brachii (both long and short heads), brachialis (3 muscles, 4 total muscle heads)
48
What muscle belly is directly pierced by the musculocutaneous nerve?
Coracobrachialis
49
What do the muscles supplied by the musculocutaneous nerve all have in common?
They all fill the anterior compartment of the arm
50
Fibers from the musculocutaneous nerve that do not supply the muscles of the anterior compartment of the arm go on to the forearm to become what nerve?
Lateral cutaneous nerve of the forearm
51
What is the supply of the lateral cutaneous nerve of the forearm?
Skin over the lateral aspect of the forearm, not the hand
52
What are the two terminal branches of the lateral cord?
Musculocutaneous and median nerves
53
What are the branches off of the medial cord of the brachial plexus?
Medial pectoral nerve, medial cutaneous nerve of the arm, medial cutaneous nerve of the forearm, ulnar nerve, and median nerve
54
The medial pectoral nerve contains fibers from what roots of the brachial plexus?
C8 and T1
55
What muscles are supplied by the medial pectoral nerve?
Pectoralis major and minor
56
What fibers of the brachial plexus are contained in the medial cutaneous nerve of the arm?
C8 and T1
57
What is the supply of the medial cutaneous nerve of the arm?
Skin of the medial arm between the axilla and the elbow
58
The medial cutaneous nerve of the arm also receives some fibers from what location?
T2 via the intercostobrachial nerve
59
What fibers make up the medial cutaneous nerve of the forearm?
C8 and T1
60
Where does the medial cutaneous nerve of the forearm leave the medial cord of the brachial plexus in reference to the medial cutaneous nerve of the arm?
Just distal to it
61
What is the supply of the medial cutaneous nerve of the forearm?
Skin over biceps brachii, skin over anterior and medial aspects of forearm distal to the wrist
62
What fibers contribute to the ulnar nerve?
C8 and T1 (sometimes C7)
63
The ulnar nerve travels medial to what artery?
Brachial artery (in the medial bicipital sulcus)
64
Does the ulnar nerve have any branches in the arm?
None
65
When the ulnar nerve reaches the elbow area, it passes under what anatomical structure?
Posterior side of medial epicondyle in the sulcus for the ulnar nerve
66
What is the lay term for the location where the ulnar nerve can be easily palpated near the elbow?
"Funny bone"
67
The ulnar nerve continues into the forearm between the two heads of what muscle?
Flexor carpi ulnaris
68
What muscle flexes digits 2-5 at the DIP joints?
Flexor digitorum profundus
69
What two muscles in the forearm are innervated by the ulnar nerve?
Flexor carpi ulnaris, flexor digitorum profundus
70
What are the two sensory branches given off in the forearm by the ulnar nerve?
Dorsal and palmar branches of the ulnar nerve
71
What does the dorsal branch of the ulnar nerve supply?
Skin on the ulnar side of the posterior hand
72
What does the palmar branch of the ulnar nerve supply?
Skin over the hypothenar eminence
73
As the ulnar nerve passes through the wrist, does it pass superficial or deep to the flexor retinaculum?
Superficial
74
What is the supply of the superficial branch of the ulnar nerve?
Skin over palmar aspect of the little finger and medial half of the ring finger
75
What are the hypothenar muscles?
Abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi
76
What muscles are supplied by the deep branch of the ulnar nerve?
Abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi, adductor pollicis, deep head of the flexor pollicis brevis, all interossei (dorsal and palmar), lumbricals 3 and 4
77
Damage to the ulnar nerve can result in what condition?
Claw hand
78
What is another term used for claw hand?
Ape hand
79
What fibers contribute to form the median nerve?
C6, C7, C8, and T1
80
What cords form the median nerve?
Both the medial and lateral cords
81
In what anatomical structure does the median nerve travel through the arm?
Medial bicipital sulcus
82
What is another term for the medial bicipital sulcus?
Bicipital furrow
83
Does the median nerve give off any branches in the arm?
No
84
When the median nerve enters the forearm, it first passes between the two heads of what muscle?
Pronator teres
85
The median nerve crosses the elbow on what side?
Anterior
86
The ulnar nerve crosses the elbow on what side?
Posterior
87
What muscles of the forearm are innervated by the median nerve?
Pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, pronator quadratus, flexor policis longus, and the lateral bellies of the flexor digitorum profundus
88
The median nerve supplies the pronator quadratus, flexor pollicis longus, and the lateral bellies of the flexor digitorum profundus by what of what nerve?
Anterior interosseous nerve of the forearm
89
What is the anterior interosseous nerve of the forearm given off of the median nerve?
In the elbow
90
What nerve passes deep to the flexor retinaculum and goes through the carpal tunnel?
Median nerve
91
Where is the palmar branch of the median nerve given off?
In the distal third of the forearm
92
What is the supply of the palmar branch of the median nerve?
Skin of the thenar eminence, lateral wrist, and palm
93
The median nerve divides into how many common palmar digital nerves after it passes through the carpal tunnel?
3
94
Which lumbricals are supplied by the median nerve?
1 and 2
95
What muscles are supplied by the branches off of the first common palmar digital nerve?
Abductor pollicis brevis, flexor pollicis brevis (superficial head), and opponens pollicis
96
What are the thenar muscles?
Abductor pollicis brevis, flexor pollicis brevis (superficial head), and opponens policis
97
Each common palmar digital nerve splits into what?
Two proper palmar digital nerves
98
Are the proper palmar digital nerves motor or sensory in function?
Sensory only
99
What do the proper palmar digital nerves supply?
Skin over the lateral three and a half digits
100
The median nerve also supplies what extra things?
Periosteum, elbow, radiocarpal joint, midcarpal joints
101
The median nerve usually communicates with what nerve at the wrist?
Ulnar nerve
102
Carpal tunnel syndrome involves the compression of what nerve?
Median nerve (not ulnar nerve)
103
What rotational movement becomes difficult with damage to the median nerve and why?
Pronation; median nerve supplies both pronator muscles
104
What fibers are contained in the superior subscapular nerve?
C5 and C6
105
What muscle is supplied by the superior subscapular nerve?
Subscapularis
106
What fibers are contained in the thoracodorsal nerve?
C6, C7, and C8
107
What muscle is supplied by the thoracodorsal nerve?
Latissimus dorsi
108
How many separate nerves contribute to the supply of the rotator cuff muscles?
4
109
What is the course of the thoracodorsal nerve?
Travels along posterior axillary wall
110
What fibers are contained in the inferior subscapular nerve?
C5 and C6
111
What muscles are supplied by the inferior subscapular nerve?
Subscapularis and teres major
112
What fibers are contained in the axillary nerve?
C5 and C6
113
What is the course of the axillary nerve?
Travels posteriorly around the surgical neck of the humerus
114
What muscles are supplied by the axillary nerve?
Anterior part of deltoid and teres minor
115
Where is the sensory branch of the axillary nerve given off?
At the same location as the branch to teres minor
116
What is the sensory branch of the axillary nerve?
Superior lateral cutaneous nerve of the arm
117
What does the superior lateral cutaneous nerve of the arm supply?
Skin over the lateral shoulder and upper arm
118
What fibers are contained in the radial nerve?
C5, C6, C7, C8, and sometimes T1
119
What general group of muscles is supplied by the radial nerve?
Posterior compartment of the arm and forearm
120
The radial nerve passes where in reference to the elbow as it passes into the forearm?
Anteriorly
121
As it enters the forearm, the radial nerve passes between what two muscles?
Brachialis and brachioradialis
122
What is the course of the radial nerve?
From medial bicipital sulcus to posterior of humerus
123
Which has sensory supply: superficial or deep branch of the radial nerve?
Superficial
124
Which has motor supply: superficial or deep branch of the radial nerve?
Deep
125
What is the course of the superficial branch of the radial nerve?
Follows brachioradialis to distal 1/3 of forearm
| Travels between brachioradialis and radius to the posterior surface of the hand
126
The deep branch of the radial nerve penetrates what muscle?
Supinator
127
The deep branch of the radial nerve terminates as what nerve?
Posterior interosseous nerve
128
Before terminating as the posterior interosseous nerve, the deep branch of the radial nerve gives off what branches?
Motor branches to supply posterior forearm muscles
129
What is supplied by the posterior cutaneous nerve of the arm?
Skin on the posterior side of the upper arm
130
Where does the posterior cutaneous nerve of the arm break off?
Upper arm
131
Where does the inferior lateral cutaneous nerve of the arm break off?
Middle arm
132
What muscles are supplied by the muscular branches of the radial nerve given off in the arm?
Triceps brachii, anconeus
133
Where is the posterior cutaneous nerve of the forearm given off?
Upper arm
134
What does the posterior cutaneous nerve of the forearm supply?
Narrow area of skin on the lateral side of the posterior forearm
135
Branches of the radial nerve given off at the lateral epicondyle supply what muscles?
Brachioradialis, extensor carpi radialis longus
136
How is the anconeus muscle supplied by the radial nerve?
By way of a branch off the branch to the medial head of the triceps brachii
137
What part of the triceps brachii is supplied by the radial nerve?
All three heads
138
The superficial branch of the radial nerve gives off what nerves?
Dorsal digital nerves
139
What do the dorsal digital nerves supply?
Radial side of posterior hand, extensor side of the thumb, extensor side of the proximal phalanges of digits 2 and 3, lateral half of the extensor side of the ring finger
140
How does the radial nerve communicate with the ulnar nerve via the superficial branch?
By giving off a communicating branch with the ulnar nerve
141
As the deep branch of the radial nerve continues as the posterior interosseous nerve, what forearm muscles are supplied?
Extensor carpi radialis brevis, supinator, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis
142
What muscles supplied by the deep branch of the radial nerve are not extensor muscles?
Supinator, abductor pollicis longus
143
Are the muscles supplied by the deep branch of the radial nerve primarily extensor or flexors?
Extensors (with two exceptions)
144
What rotational movement is made possible by the radial nerve's motor supply?
Supination (supplies supinator)
145
The radial nerve sends articular branches to what locations?
Shoulder and wrist (NOT ELBOW)
146
Wrist drop is a clinical condition involving damage to what nerve?
Radial nerve
147
What reflexes are impaired due to radial nerve damage?
Triceps and brachioradialis reflexes
148
How can you test for wrist drop with a patient?
Have their arm parallel to the floor in a pronated position, and see if they can extend their arm so their fingers are pointed to the ceiling (if unable to do so, radial nerve is damaged and wrist drop is present)
149
What visual clinical hand sign is seen with damage to the median nerve?
"Benediction/hand of oath"
| Thumb, index, and middle fingers up with ring and pinky fingers curled down
150
What is the largest branch of the posterior cord of the brachial plexus?
Radial nerve
151
What is Erb-Duchenne palsy?
Damage to the upper part of the brachial plexus, specifically the C5 and C6 roots
152
What kind of injury can result in Erb-Duchenne palsy?
Any injury that tractions the shoulder downward (example = birth trauma)
153
What nerves are affected by Erb-Duchenne palsy?
Suprascapular, musculocutaneous, and axillary nerves
154
What muscles exhibit atrophy from Erb-Duchenne palsy?
Brachialis, biceps brachii, deltoid
155
The "waiter's tip" hand gesture is seen with what condition from damage to the brachial plexus?
Erb-Duchenne palsy
156
What palsy results from damage to the C8 and T1 roots of the brachial plexus?
Dejerine-Klumpke's palsy
157
What muscles are affected by Klumpke's palsy?
Hand muscles (atrophy of thenar and hypothenar eminences), interossei, flexor carpi ulnaris, medial half of the flexor digitorum profundus
158
What sympathetic eye condition is seen due to damage to the T1 root of the brachial plexus in Klumpke's palsy?
Horner's syndrome
