Lecture 6: Intro to brachial plexus and shoulder girdle muscles Flashcards

1
Q

What is the major nerve network supplying the upper limb?

A

Brachial Plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The brachial plexus s formed by the union of what?

A

Anterior Rami (C5-T1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is the gap that the brachial plexus passes through?

A

Between the anterior and middle scalene muscles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In the inferior part of the neck, the roots of the brachial plexus unite to form what three trunks?

A

-Superior Trunk (C5 & C6)
-Middle Trunk (continuation of C7)
-Inferior Trunk (C8 & T1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

As the brachial plexus passes posterior to the clavicle it divides into two compartments, what are these compartments?

A

-Anterior (flexor) compartment
-Posterior (extensor) compartment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The division of the brachial plexus forms three chords. What are they?

A

1) Anterior divisions of the superior and middle trunks
2) Anterior division of the inferior trunk
3) Posterior divisions of all three trunks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Anterior divisions of the superior and middle trunks form what?

A

Lateral chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Anterior division of the inferior trunk form what?

A

Medial chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Posterior divisions of all three trunks form what?

A

Posterior chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The brachial plexus is divided into what two parts by the clavicle?

A

Supraclavicular & Infraclavicular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the four branches of the supraclavicular part of the plexus?

A

1) Dorsal scapular nerve (C5 root)
2) Long thoracic nerve (C5,6,7)
3) Nerve to subclavius (From superior trunk)
4) Suprascapular nerve (from superior trunk)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The median and lateral cords of the plexus join to form what?

A

Median nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What parts make up the infraclavicular part of the plexus?

A

-Branches of the lateral cord
-Branches of the medial cord
-Branches of the posterior cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the branches of the the lateral cord?

A

1) Lateral pectoral nerve
2) Musculocutaneous nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the branches of the medial cord?

A

1) Medial pectoral nerve
2) Medial cutaneous nerve of arm
3) Medial cutaneous nerve of forearm
4) Ulnar nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the branches of the posterior cord?

A

1) upper subscapular nerve
2) Thoracodorsal nerve
3) Lower subscapular nerve
4) Axillary Nerve
5) Radial nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Review nerves and locations on back of card:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The brachial plexus in situ:

A

-Lateral to cervical spine
- Passes through scalene muscles
-Heads inferolaterally to travel underneath the clavicle and enter the axilla/armpit
-Associated with arterial supply of upper limb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The subclavian artery transitions to what as it passes under the clavicle?

A

Axillary artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the formation of the plexus?
-Remember “5-3-6-3-5
“Real Texans Drink Cold Beer”

A

5 roots
3 trunks
6 divisions
3 cords
5 terminal branches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the arrangement of the terminal branches? “MARMU”

A

Musculocutaneous
Axillary
Radial
Median
Ulnar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the roots of the brachial plexus?

A

Anterior branches of fully formed spinal nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which nerves make up the brachial plexus?

A

C5,6,7,8 & T1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which trunks make up the brachial plexus?

A

Superior, Middle. Inferior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How many divisions?
6 divisions -2 (superior trunk) -2 (middle trunk) -2 (inferior trunk)
26
Where do the 6 divisions pass under?
Clavicle and head towards the axilla
27
After the brachial plexus enters the axilla, they combine together to form three cords.
Lateral Posterior Medial (their positions are named relative to the axillary artery)
28
The brachial plexus cords then form the terminal branches, what are they?
-musculocutaneous nerve (lateral cord) -Axillary & Radial nerves (Posterior cord -Median nerve (lateral & medial cord) -Ulnar nerve (medial cord)
29
Which part of the brachial plexus passes through the scalenes muscles in the neck?
Roots
30
Review nerve locations:
31
What are the origins and insertions of the trapezius muscle?
O: upper trap-External occipital protuberance & the medial superior nuchal line of the occipital bone, the ligamentum nuchae, the SP's of C7 Middle trap: SP of T1-T5 Lower trap: SP of T6-T12 I: Lateral 1/3 of clavicle; acromion, spine of scapula
32
What action do the upper traps perform?
Elevation and upwardly rotate the scapula & extend the neck
33
What action do the middle traps perform?
Retraction of the scapula
34
What action do the lower traps perform?
Depression and aid in upward rotation of the scapula
35
What is the origin and insertion of the rhomboids minor?
O: SP's of C7-T1 I: Medial (vertebral) border of scapula at the root of the spine
36
What are the origins and insertions of rhomboids major?
O: SP's of T2-T5 I: Medial (vertebral) border of scapula inferior to spine
37
What actions do the rhomboids perform?
Upward rotation and downward rotation
38
What are the origins and insertions of levator scapula?
O: TP's of C1-C4 I: Medial border of the scapulae (above the spine of the scapula)
39
What are the actions of the levator scapulae?
Elevate the scapula
40
What are the origins and insertions of Pectoralis minor?
O: 3rd-5th rib I: Coracoid process
41
What nerve innervates the pectoralis minor?
Medial nerve
42
What nerve innervates the rhomboids?
Dorsal scapular
43
What nerve innervates the traps?
Spinal accessory nerve (CN XI)
44
What are the actions of the pectoralis minor?
-stabilization, depression, abduction or protraction, internal rotation, and downward rotation of the scapula
45
What is the origin and insertion of the Subclavius?
O: First rib I: Subclavian groove of the clavicle
46
What nerve innervates the subclavius?
Nerve to subclavius
47
What is the origin and insertion of Serratus anterior?
O: upper 9 ribs I; Anterior surface of vertebral (medial) border of scapula
48
What nerve innervates the serratus anterior?
Long thoracic nerve (C5,6,7)
49
What is paralysis of the serratus anterior, due to injury of the long thoracic nerve called?
Winged scapula
50
What happens during winged scapula?
Inferior angle of the medial border of the scapula is excessively prominent.
51
What actions does winged scapula make difficult?
Pushing actions or raising arm above head
52
What are the origins and insertions of the pectoralis major?
O: Clavicular head-Medial half of clavicle. -Sternocostal head -sternum & costal cartilages of 1st to 7th ribs I: lateral lip of intertubular (bicipital) groove of the humerus
53
What are the actions of the pectoralis major?
Horizontal adduction
54
What are the origins and insertions of the latissimus dorsi?
O: SP's of T7-L5 Crest of ilium & sacrum Lowest four ribs (via thoracolumbar fascia) I: Floor of the intertubercular groove of the humerus
55
What nerve innervates the latissimus dorsi?
Thoracodorsal
56
What actions does the latissimus dorsi perform?
Internal rotation, adduction, and extension of the arm
57
What are the origins and insertions of the deltoid muscle?
O: lateral clavicle (anterior fibers) acromion (lateral fibers) Spine of the scapula (posterior fibers) I: Deltoid tuberosity of humerus
58
What nerve innervates the deltoid?
Axillary
59
What are the origins and insertions of the subscapularis?
O: Subscapular fossa I: lesser tubercle of the humerus
60
What nerve innervates the subscapularis?
Upper and lower subscapularis
61
What are the origins and insertions of the Supraspinatus?
O: Supraspinous fossa I: Greater tubercle of humerus
62
What nerve innervates the supraspinatus?
Suprascapular nerve
63
What are the origins and insertions of the infraspinatus?
O: infraspinous fossa I: Greater tubercle of humerus
64
What nerve innervates the infraspinatus?
Suprascapular nerve
65
What are the origins and insertions of the Teres minor?
O: The superior lateral border of scapula I: Greater tubercle of humerus
66
What nerve innervates the teres minor?
Axillary nerve
67
What are the origins and insertions of the teres major?
O: The inferior lateral border of the scapula I: Medial lip of intertubercular (bicipital) sulcus (groove) of humerus
68
What nerve innervates the teres major?
Upper and lower subscapular nerve
69
What muscles are included in the rotator cuff?
1) Supraspinatus 2) Infraspinatus 3) Teres minor 4) Subscapularis
70
What is the roll of the rotator cuff?
Strengthen the shoulder capsule all around except inferiorly.
71
In which direction it is most common to dislocate the humerus?
Downward direction
72
Review axillary spaces: