B6.004 Shoulder, Axilla, Brachial Plexus, Arm Flashcards
1
Q
what are extrinsic shoulder muscles
A
muscles have attachments to the thoracic wall
thoracoappendicular
2
Q
what are the extrinsic shoulder muscles
A
4 anterior: pec major, pec minor, subclavius, serratus anterior
4 posterior: superficial - trapezius, latissimus dorsi and deep - levator scapulae, rhomboids
3
Q
what are intrinsic shoulder muscles
A
muscles only attach to shoulder bones
scapulohumeral
4
Q
what are the intrinsic shoulder muscles
A
deltoid
teres major
4 rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis)
5
Q
pec major orientation
A
forms anterior wall of axilla
inferior border forms anterior axillary fold
forms deltopectoral triangle w deltoid and clavicle
6
Q
vein in pec major
A
cephalic vein runs in deltopectoral triangle/groove
7
Q
innervation of pec major
A
medial and lateral pectoral nerves
8
Q
function of pec major
A
adducts and medially rotates the humerus
9
Q
origin of pec major
A
3 origins
clavicle
sternum
costal cartilage
10
Q
insertion of pec major
A
lateral lip of intertubercular groove on humerus
twists on itself when arm is adducted
11
Q
how can you rupture your pec major insertion
A
bench pressing too much weight
hurt a lot and take months to recover after surgery
12
Q
orientation of pec minor
A
deep to the pec major
13
Q
insertion of pec minor
A
coracoid of scapula
14
Q
origin of pec minor
A
ribs 3,4,5
15
Q
function of pec minor
A
fixes scapula to thoracic wall
stretch arms forward/upward to touch an object our of reach
helps with inspiration by lifting ribs
16
Q
innervation of pec minor
A
medial pectoral nerve
17
Q
orientation of serratus anterior
A
medial wall of axilla
18
Q
function of serratus anterior
A
protracts the scapula when reaching anteriorly
rotates inferior angle of the scapula so glenoid cavity is raised when arm is above shoulder
holds scapula against thoracic wall
19
Q
insertion of serratus anterior
A
anterior surface of medial border of scapula
20
Q
origin of serratus anterior
A
external surface of ribs 2-8
21
Q
innervation of serratus anterior
A
long thoracic nerve
SALT
22
Q
cause of paralysis of serratus anterior
A
injury to long thoracic nerve or any injury above this nerve’s spinal level
23
Q
appearance of paralysis of serratus anterior
A
winged scapula
medial border and inferior angle of scapula is markedly pulled away from the posterior thoracic wall
arm cannot abduct above horizontal because serratus anterior is used to pull the inferior scapula laterally
24
Q
function of trapezius
A
superior - elevates scapula
middle - retract (adducts) the scapula
inferior - depress the scapula and lower the shoulder
involved in scapular rotation w cooperation between superior and inferior fibers
25
insertions of trapezius
acromion
| spine of scapula
26
origins of trapezius
superior nuchal line
C7
T12
27
how do you test the trapezius
shrug against resistance
28
innervations of trapezius
spinal accessory nerve CN X1
29
function of latissimus dorsi
extends, adducts, and medially rotates the humerus
brings body towards arms when climbing
forms part of posterior wall of axilla
30
innervation of latissimus dorsi
thoracodorsal nerve
31
origin of latissimus dorsi
T7-12
thoracolumbar fascia
iliac crest
32
insertion of latissimus dorsi
intertubercular groove of humerus (medial lip)
| superior fibers insert inferiorly on humerus (twisting when arm is adducted)
33
what do trapezius and lat dorsi have in common
both superficial back muscles and muscles of the upper extremity
34
injury to thoracodorsal nerve
can be injured in surgery (radical breast dissections)
if injured, patient cannot use axillary crutch because there will be no counter force for the shoulder when it is pushed up by the crutch
cannot do pull ups
35
orientation of levator scapulae
superior 1/3 lies deep to the SCM
| inferior 1/3 lies deep to trapezius
36
origin of levator scapulae
transverse process of C1-C4
37
insertion of levator scapulae
medial border of scapula, cranial to spine of scapula
38
function of levator scapulae
elevate and rotate scapula
39
innervation of levator scapulae
dorsal scapular nerve
40
orientation of rhomboid muscles
deep to trapezius
| cannot be seen, but can be palpated
41
innervation of rhomboids
dorsal scapular nerve
42
origins of rhomboids
minor: C7-T1
major: T2-T5
43
insertion of rhomboids
medial borders of scapula
44
rhomboid test
patient lie prone with hand over small of back
| ask patient to lift hand off which hand on rhomboid
45
function of rhomboids
adduct, retract the scapula toward the middle of the back
46
function of deltoid
cannot initiate abduction when arm is fully adducts (assisted by supraspinatus for first 15 degrees)
stabilized shoulder joint by holding head of humerus in the glenoid cavity during movement
anterior part - flex shoulder
posterior part - extend shoulder
47
innervation of deltoid
axillary nerve
48
origins of deltoid
acromion
spine of scapula
clavicle
49
insertion of deltoid
deltoid tuberosity
50
causes of damage to axillary nerve
shoulder joint dislocation
humeral surgical neck fracture
intramuscular injection
51
appearance of damage to axillary nerve
loss of sensation on lateral side of proximal arm skin
| loss of shoulder contour
52
deltoid muscle test
abduction of shoulder beyond 15 degrees
53
orientation of teres major muscle
inferior border of the posterior wall of the axilla
| intercepts with long head of triceps to form triangular space and quadrangular space
54
function of teres major
stabilizes humeral head
counteracts deltoid during abduction
adduction of humerus
medially rotates the humerus
55
origin of teres major
inferior angle of scapula
56
insertion of teres major
medial lip of interturbercular groove
57
innervation of teres major
lower subscapular nerve
58
importance of triangular space
exits circumflex scapular artery
59
important of quadrangular space
exits posterior circumflex humeral artery and axillary nerve
60
rotator cuff muscles
```
supraspinatus
infraspinatus
teres minor
subscapularis
SItS
```
61
function of rotator cuff
stabilize the shoulder and secure humeral head in the glenoid (ALL)
abduct arm- supraspinatus helps with initial 15
adduct the arm - subscapularis, teres minor
medial rotation - subscapularis, teres major
lateral roation- infraspinatus, teres minor
62
shoulder exam of infraspinatus and teres minor
lateral rotators
| patient rotates forearm against resistant
63
shoulder exam of subscapularis
lift off test
patient lifts hand off the small of back against resistant
tests medial rotation of shoulder joint
64
shoulder exam of supraspinatus
empty can test
arms extended held 90 abduction with 30 flexion anteriors
turn thumbs down and elevate arms against resistant
65
most frequently compromised muscle of rotator cuff
supraspinatus
| can be compressed during shoulder abduction by acromion
66
what is a bursa
small viscous fluid filled sac lined by synovial membrane
| completely separate from glenohumeral joint capsule
67
causes of rotator cuff injuries
falls
avoiding crashing into an object using the arm
throwing a ball hard
shoulder joint dislocation
68
result of rotator cuff injuries
pain in anterosuperior part of the shoulder
| shoulder joint dislocation
69
test for rotator cuff injuries
ask patient to lower a fully abducted arm slowly and smoothly
drop arm test
70
epidemiology of rotator cuff injuries
2 million people in US in 2013
presents w dull ache in shoulder, worsened by sleeping on it
most often in repeated overhead motion
71
subacromial bursitis and calcification / supraspinatus tendonitis
occurs between tendon of supraspinatus and the acromion, coracoid ligament, and deltoid
72
result of subacromial bursitis and calcification / supraspinatus tendonitis
pain during abduction in 50-130 degree range
| painful arc syndrome
73
triangular space
circumflex scapular artery
74
quadrangular space
axillary nerve
| posterior circumflex humeral artery
75
triceps hiatus / triangular interval
radial nerve
| profundal brachii artery
76
what is the axilla
pyramidal shaped space between arm and thorax providing a passage for vessels and nerves to reach the upper limb
neurovascular structures are ensheathed in a fascial sleeve called axillary sheath
77
origin of axillary artery
continues from subclavian arty just lateral to first rib
78
how many branches of axillary artery?
3 parts
| 6 branches
79
first part of axillary artery
superior thoracic artery
80
second part of axillary artery
thoracoacromial
| lateral thoracic artery
81
third part of axillary artery
subscapular
| anterior and posterior circumflex humeral arteries
82
lateral thoracic artery
important source of blood to lateral part of mammary gland in women
runs with long thoracic nerve to serratus anterior
83
subscapular artery
largest branch of axillary artery
| divides into circumflex scapular and thoracodorsal arteries
84
circumflex scapular artery
supplies subscapularis and teres major
85
thoracodorsal artery
supplies lat dorsi
86
circumflex humeral arteries
anterior and posterior anastomose w each other and supplies delt, teres major and minor, and long head of triceps
87
compression of the axillary artery
do this when there is heavy bleeding of the arm
2 compression locations
1. distal part of axillary artery, palpate the inferior part of the lateral wall of the axilla against the humeral bone
2. at beginning of artery, downward pressure in the angle between the clavicle and the attachment of SCM muscle against 1st rib
88
mnemonic for axillary artery branches
1: Superior thoracic
2: Thoracoacromial
Lateral thoracic
3: Subscapular
Anterior
Posterior circumflex humeral
"screw the lawyer, save a patient"
89
axillary lymph node dissection
```
2 vulnerable nerves
long thoracic nerve (serratus anterior, winged scapula if cut)
thoracodosal nerve (lat dorsi)
```
90
location of brachial plexus
C5-T1
91
overview of brachial plexus
union of anterior rami of C5, C6, C7, C8, and T1
begins in neck and extends into axilla
carries nerve fibers from motor neurons, sensory neurons, and autonomic (sympathetic) neurons
92
5 sections of the brachial plexus
```
roots -5
trunks -3
divisions - 6
cords - 3
terminal branches -5
```
93
roots of brachial plexus
C5-8
| T1
94
3 nerves given out of roots of brachial plexus
```
dorsal scapular (C5)
phrenic (C3,4,5)
long thoracic (C5,6,7)
```
95
dorsal scapular nerve
rhomboids and levator scapulae
96
phrenic nerve
diaphragm
97
long thoracic nerve
serratus anterior
| C5,6,7 wings to heaven
98
anatomy of long thoracic nerve
travels between middle and posterior scalene muscles
hypertrophy of these muscles (Swimmers) can cause compression and loss of function
SUPERFICIAL to serratus anterior (rare)
99
3 trunks of brachial plexus
superior
middle
inferior
100
superior trunk of brachial plexus
union of C5 and C6 roots
give out 2 nerves
1. subclavius
2. suprascapular nerve (C4,5,6)
101
suprascapular nerve
supraspinatus
infraspinatus
glenoid joint
102
middle trunk of brachial plexus
continuation of C7 root
103
inferior trunk of brachial plexus
union of C8 and T1
104
3 cords of brachial plexus
lateral
posterior
medial
named for relationship to axillary artery
105
lateral cord
union of anterior division of superior and middle trunks
| carry fibers from C5,6,7
106
branch off of lateral cord
lateral pectoral nerve (C5,6,7)
107
lateral pectoral nerve
innervates pec major
108
medial cord
formed from continuation of the anterior division of the inferior trunk
fibers from C8-T1
three branches
109
branches off medial cord
medial pectoral nerve (C8, t1)
medial cutaneous nerve of arm (C8, T1)
medial cutaneous nerve of the forearm (C8,T1)
110
medial pectoral nerve
pec major and minor
111
medial cutaneous nerve of arm
supplies skin on medial side of the arm and superior part of the forearm
112
medial cutaneous nerve of the forearm
supplies skin on medial side of forearm
113
posterior cord
formed by posterior divisions of all 3 trunks
carrying fibers from C5-T1
three branches
114
branches off posterior cord
```
upper subscapular (C5,6)
thoracodorsal (C6,7)
lower subscapular (C6,7)
```
115
upper subscapular nerve
subscapularis
116
thoracodorsal nerve
lat dorsi
117
lower subscapular nerve
teres major
| inferior subscapularis
118
anatomy of thoracodorsal
travels with thoracodorsal artery to lat dorsi
119
5 terminal branches
```
musculocutaneous - lat cord
axillary - post cord
median - lat and med cords
radial - post cord
ulnar - med cord
```
120
mnemonic for branches
most alcoholics must really urinate
121
anatomy of axillary nerve
quadrangular space
122
axillary nerve
deltoid
skin over lower half of deltoid
teres minor
abducts shoulder
123
fracture of the surgical neck
can damage axillary nerve
common in elderly due to FOOSH
fracture may be stable due to ligaments surrounding this region
124
injury of the axillary nerve
loss of sensation on skin of medial shoulder
125
test for injury of axillary nerve
abduction of the shoulder joint beyond the first 15 degrees and continued abduction against resistant
126
musculocutaneous nerve
innervates all 3 muscles in anterior compartment of the arm
| flexes shoulder and elbow
127
branches of musculocutaneous nerve
coracobrachialis
biceps
brachialis
lateral cutaneous nerve of forearm
128
radial nerve
innervates all posterior arm muscles
innervates all 11 posterior compartment forearms muscles
extends shoulder, elbow, and wrist
129
nerve and vessel injuries related to humerus fractures
surgical neck = axillary nerve
mid humeral = radial nerve and deep arm vessels
distal end = median nerve (rare)
medial epicondyle = ulnar nerve
130
radial nerve injury
before triceps: paralysis of triceps (loss of elbow extension), brachioradialis, supinator and extensor muscles of the wrist and digits. loss of sensation on back of hand over first 3 fingers.
after triceps: same except triceps still functions (can extend elbow)
131
radial neuropathy
Saturday night palsy
wrist and finger drop
numbness in hand
weak supination and elbow flex
132
median nerve
innervates all anterior compartment muscles of forearm except 1.5 (innervated by ulnar)
flexes wrist and fingers
3 thumb muscles and 1/2 lumbricles
133
ulnar nerve
innervates 1.5 forearm muscles (flexor carpi ulnaris and half of flexor digitorum profundus)
innervates all hand muscles
134
relationship between roots and terminal branches
axillary- C5,6
musculocutaneous - C5,6,7
ulnar- C8,T1
median and radial- C5-T1
135
cause of brachial plexus injuries
mechanical, sometimes cancer
136
presentation of brachial plexus injuries
paralysis or anesthesia
137
superior brachial plexus injuries
C5,6
| Erb's palsy
138
inferior brachial plexus injuries
C8.T1
| Klumpkes palsy
139
causes of erbs palsy
excessive separation of the head and neck such as falling with shoulder on ground
shoulder dystocia, head delivers but babies shoulders get stuck in birth canal causing excessive stretching of babies head from shoulder(1-3 per 1000)
140
appearance of erbs palsy
waiter tip position
limb hangs at side in medial rotation
loss of sensation on lateral aspect of limb down to thumb
141
nerves injured in erbs pals
suprascapular
musculocutaneous
axillary
142
muscle paralysis in erbs
```
supraspinatus
infraspinatus
deltoid
biceps
brachialis
brachioradialis
```
143
cause of klumpkes palsy
sudden pull of arm superiorly such as grasping a tree during a fall
144
appearance of klumpkes palsy
short muscles of hand form a claw when trying to form a fist
similar to ulnar nerve damage
rare
145
brachial plexitis
sharp, severe sudden onset pain in nerves of brachial plexus or a portion
weakness, pain and atrophy follow
unknown cause
146
treatment of brachial plexitis
corticosteroids and gabapentin
teakes months to slowly improve
2-3 years for recovery, some have permanent damage
147
2 compartments of arm muscles
anterior: biceps brachii, brachialis, coracobrachialis
posterior: triceps brachii, anconeous
148
anterior compartment of arm muscles
flexors
| musculocutaneous innervation
149
posterior compartment of arm muscles
extensors of elbow
| innervated by radial nerve
150
proximal origins of biceps brachii
short head from coracoid process
| long head from supraglenoid tubercle
151
path of long head of biceps brachii
runs through glenohumeral joint, surrounded by synovial membrane, then over the head of the humerus, inside the intertubercular groove where it is fixed by the transverse humeral ligament
152
insertions of biceps brachii
distal end forms a tendon which attaches to the tuberosity of the radius
distal end continues as the bicipital aponeurosis, a membranous band that runs from the biceps tendon around the cubital fossa and merges with antebrachial fascia
153
bicipital aponeurosis
protects brachial artery and medial nerve in the cubital fossa, esp during median cubital vein
154
function of biceps brachii
flexes arm and forearm
| supinates the forearm when elbow is flexed at 90 degrees
155
biceps tendinitis
affects the tendon of the long head which is enclosed by a synovial sheath and lies in the intertubercular groove
caused by repetitive microtrauma
similar pain levels w active and passive motion
156
subluxation/dislocation of the tendon of the long head of the biceps
may be caused by tendinitis and a traumatic separation of the proximal epiphysis of the humerus
disruption of the transverse humeral ligament
associated with rotator cuff injury 70% of the time
157
symptoms of subluxation/dislocation of the tendon of the long head of the biceps
popping or catching sensation in anterior shoulder
| particularly when shoulder is abducted to 90 degrees
158
rupture of the tendon of the long head of the biceps
causes: excessive forceful flexion of the arms or wear and tear of an inflamed tendon
appearance: popeye deformity, ball near center of the distal part of the anterior aspect of the arm
may also avulse its insertion into radial tuberosity or rarely tear the central belly of the muscle
159
dislocation of proximal humeral epiphysis
happens to children or adolescents when arm or shoulder is directly hit by a flow
160
brachialis muscle orientation
deep to biceps
161
origin of brachialis
distal half of anterior surface of humerus
162
insertion of brachialis
coronoid process and tuberosity of ulna
163
innervation of brachialis
musculocutaneous
164
function of brachialis
elbow flexor
165
origin of coracobrachialis
coracoid process
166
insertion of coracobrachialis
mid 1/3 of humerus
167
innervation of coracobrachialis
musculocutaneous
| PIERCES this muscle and innervates it
168
function of coracobrachialis
flexes and adducts shoulder
| stabilizes glenohumeral joint
169
anatomy of coracobrachialis
median nerve and humeral artery run deep
| musculocutaneous runs anterior to the inferior part of the muscle
170
origin of triceps
long head - infraglenoid tubercle
lateral head - posterior of humerus
medial head - distal posterior humerus
171
insertion of triceps
olecronon process of ulna
172
function of triceps
extends elbow
| adduction and extends shoulder
173
triceps test
abduct arms 90 degrees
| extend elbow joint against resistance
174
innervation of triceps
radial nerve
175
brachial artery anatomy
starts from inferior teres major and ends in cubital fossa under the bicipital aponeurosis
divides into radial and ulnar arteries
176
profundal brachii
deep artery of the arm
largest branch of brachial artery, accompanies radial nerve through radial groove
divides around elbow joint
177
2 groups of arm veins
1. superficial - runs in the subQ tissue
| 2. deep - runs along with arteries
178
superficial veins of arm
cephalic
basilic
median cubital
179
cephalic vein
anterolateral surface of proximal forearm and arm
| pass through deltopectoral groove and deltopectoral triangle into axillary vein
180
basilic vein
medial side of inferior arm
| merge with veins accompanying brachial artery to for axillary vein
181
median cubital vein
2 veins forms anastomoses in the forearm and communicate in the cubital fossa
182
result of musculocutaneous nerve injury
paralysis of coracobrachialis, biceps, and brachialis
weakened shoulder flexions
weakened forearm flexion and supination
loss of sensation on lateral forearm
183
what is the cubital fossa
hollow area on the anterior aspect of the elbow
contains: brachial artery (and radial and ulnar branches), deep veins, biceps brachii tendon, median nerve, radial nerve branches
184
venipuncture from cutaneous vein
median cubital vein is a common location of blood sampling, infusion, injection, and cath
