Axilla and Brachial Plexus

Question 1

A pyramidal shaped space which contains fat and many neurovascular structures. It is considered the portal to the upper limb from the neck

Answer 1

Axilla

Question 2

The arterial supply, venous drainage, lymphatic drainage and nerve supply of the upper limb all pass through the

Answer 2

Axilla

Question 3

The axilla contains many lymph nodes which receive drainage from the

Answer 3

Upper limb, anterior chest wall (including breast), back, and neck

Question 4

What is the structure of the axilla?

Answer 4

Three walls, a apex, and a base (triangular pyramid)

Question 5

The ANTERIOR wall of the axilla is composed of the

Answer 5

Pectoralis major and pectoralis minor

Question 6

The POSTERIOR wall of the axilla is composed of the

Answer 6

Subscapularis, latissimus dorsi, and teres major

Question 7

The MEDIAL wall of the axilla is composed of the

Answer 7

Serratus anterior

Question 8

Formed by the bicipital groove of the humerus, where the anterior and posterior walls converge

Answer 8

Lateral “wall” of axilla

Question 9

Attaches to the lateral lip of the groove

Answer 9

Pectoralis major

Question 10

Attaches to the floor of the groove

Answer 10

Latissimus dorsi

Question 11

The groove contains the tendon of the long head of the

Answer 11

Biceps femoris

Question 12

An aperture between the clavicle and the first rib which communicates between the axilla and the base of
the neck

Answer 12

Upper apex of the axilla

Question 13

Contains fat, lymph nodes, neurovascular structures, short head of biceps brachii and coracobrachialis

Answer 13

Axilla

Question 14

The continuation of the subclavian artery (changes its name as it passes the first rib and enters this structure)

Answer 14

Axillary artery

Question 15

The pectoralis minor muscle crosses in front of the axillary artery and divides the artery into which three parts?

Answer 15

1st part: proximal to the pec minor
2nd part: behind the pec minor
3rd part: distal to the pec minor

Question 16

The third part ends as the artery passes the inferior border of the teres major muscle (thus leaving the axilla and entering the arm), where it is continuous with the

Answer 16

Brachial Artery

Question 17

The axillary artery has six branches in the axilla. The 1st part has one branch called the

Answer 17

Superior thoracic artery

Question 18

The 2nd part of the axillary artery has two branches, called the

Answer 18

Thoracoacromial artery and lateral thoracic artery

Question 19

The 3rd part of the axillary artery has three branches, called the

Answer 19

Subscapular, anterior humeral circumflex, and posterior humeral circumflex arteries

Question 20

The nerve supply to the upper limb: provides the sensory and motor innervation to the upper limb

Answer 20

Brachial Plexus

Question 21

The brachial plexus arises from nerves in the

Answer 21

Neck and upper thorax

Question 22

The portion of the brachial plexus within the axilla consists mostly of the

Answer 22

Cords of the plexus

Question 23

The three cords surround the axillary artery and are named according to their position relative to the artery. They are called the

Answer 23

Lateral, medial, and posterior cords

Question 24

Connective tissue which surrounds the axillary artery and brachial plexus

-an evagination of deep fascia of the neck

Answer 24

Axillary sheath

Question 25

Because the axillary sheath holds the elements of the brachial plexus against the axillary artery, the nerves may be compressed by

Answer 25

Aneurysms of the artery

Question 26

The proximal continuation of the basilic vein which changes its name when it crosses the lower border of the teres major to enter the axilla

Answer 26

Axillary vein

Question 27

In addition to receiving other deep veins within the axilla, the axillary vein receives the

Answer 27

Cephalic vein

Question 28

The axillary vein is NOT within the axillary sheath, rather it is

Answer 28

Anterior to the sheath

Question 29

Important clinically due to their drainage of the breast. | Also receives drainage from the upper limb, chest wall, neck and back

Answer 29

Axillary lymph nodes

Question 30

Axillary lymph nodes drain to the subclavian lymph trunk which, on the left, drains into the

Answer 30

Thoracic duct

Question 31

Axillary lymph nodes drain to the subclavian lymph trunk which, on the right, drains into the

Answer 31

Right lymphatic duct

Question 32

Receive drainage from the anterior chest wall and breast

Answer 32

Anterior axillary lymph nodes

Question 33

Receive drainage from the posterior chest wall

Answer 33

Posterior axillary lymph nodes

Question 34

Receive drainage from the upper limb

Answer 34

Lateral axillary lymph nodes

Question 35

The anterior, lateral, and posterior lymph nodes drain into the

Answer 35

Central and apical nodes

Question 36

The efferent drainage from the apical nodes forms the

Answer 36

Subclavian trunk

Question 37

Because of this anatomy, the anterior, central, and apical axillary lymph nodes are interposed in the pathway of cancerous emboli from the breast before they reach the

Answer 37

Venous blood stream

Question 38

Allows for directed and accurate assessment of axillary involvement in breast cancer with minimal morbidity -Replacing axillary lymph node dissection (ALND) as go to treatment

Answer 38

Sentinel lymph node biopsy (SLNB)

Question 39

A colored dye and a radioactive dye are injected into the region of the tumor and then the very few lymph nodes to which the dye drains are removed

Answer 39

SLNB

Question 40

A network of nerve fibers that arise from multiple sources, intermingle, and then give rise to nerves that contain nerve fibers from these multiple sources

Answer 40

Nerve plexus

Question 41

In the case of the brachial plexus, the multiple sources of nerve fibers are the anterior rami of

Answer 41

C5 through T1

Question 42

These fibers intermingle in the trunks and cords of the plexus and then give rise to nerves that contain combinations of nerve fibers from different spinal level between

Answer 42

C5 and T1

Question 43

The radial nerve contains nerve fibers from

Answer 43

C5, C6, C7, and C8

Question 44

The musculotaneous nerve contains nerve fibers from

Answer 44

C5, C6, and C7

Question 45

The median nerve contains nerve fibers from

Answer 45

C6,C7, C8, and T1

Question 46

Begins in the neck (supraclavicular portion) and continues into the axilla (infraclaviculr portion)

Answer 46

Brachial plexus

Question 47

As the nerve fibers pass from the neck to the axilla, they sort themselves into

Answer 47

Anterior and posterior divisions (distribute to anterior and posterior portions of the limb)

Question 48

These divisions will then be bundled together by connective tissue into three

Answer 48

Cords

Question 49

The lateral and medial cords contain only

Answer 49

Anterior division nerve fibers

Question 50

The posterior cord contains only

Answer 50

Posterior division nerve fibers

Question 51

The cords divide to give rise to the

Answer 51

Terminal nerves

Question 52

What are three nerves that contain anterior division fibers?

Answer 52

Musculotaneous, median, and ulnar nerves

Question 53

What are two nerves that contain posterior division fibers?

Answer 53

Radial and axillary nerves

Question 54

Within the brachial plexus, collateral nerves arise which innervate proximal structures in the

Answer 54

Shoulder and axilla regions

Question 55

Innervate the muscles that form the posterior wall of the axilla

Answer 55

The three subscapular nerves (from posterior cord)

Question 56

The lateral and medial pectoral nerves (from lateral and medial cords) innervate the muscles that form the

Answer 56

Anterior wall of the axilla

Question 57

Innervates the muscle on the medial wall of the axilla

Answer 57

Long thoracic Nerve

Question 58

The dorsal scapular and suprascapular nerves innervate muscles of the

Answer 58

Shoulder girdle

Question 59

Innervates all of the muscles of the anterior compartment of the arm

Answer 59

Musculocutaneous nerve

Question 60

Innervates most of the muscles of the anterior compartment of the forearm (the remaining muscles are innervated by the ulnar nerve)

Answer 60

Median nerve

Question 61

Innervates most of the muscles of the anterior compartment of the hand (the remaining muscles are innervated by the median nerve)

Answer 61

Ulnar nerve

Question 62

Innervates all of the muscles of the posterior compartment of the arm and forearm

Answer 62

Radial nerve

Question 63

Innervates only two muscles, the deltoid and teres minor

Answer 63

Axillary nerve

Question 64

In the upper limb, the more proximal muscles are innervated by the

Answer 64

Higher spinal cord segments

Question 65

The more distal muscles of the upper limb are innervated by

Answer 65

Lower spinal cord segments

Question 66

The muscles of the shoulder are innervated by

Answer 66

C5 and C6

Question 67

The muscles of the hand are innervated by

Answer 67

C8 and T1

Question 68

This means, for example, that although the median nerve contains nerve fibers from C6 through T1, the branches of the median nerve that innervate: 1. ) proximal forearm muscles 2. ) distal forearm muscles 3. ) hand muscles Contain fibers from?

Answer 68

1. ) C6 and C7 2. ) C7 and C8 3. ) C8 and T1

Question 69

Also provide cutaneous innervation

Answer 69

Nerves of the brachial plexus

Question 70

The most important region clinically for cutaneous innervation is the

Answer 70

Hand

Question 71

The palmar surface of the hand receives cutaneous sensory information from the

Answer 71

Median and Ulnar nerves

Question 72

The dorsum of the hand receives cutaneous sensory innervation from the

Answer 72

Radial and Ulnar nerves (w/ small contribution from median nerve)

Question 73

The segmental distribution of cutaneous sensory innervation is called the

Answer 73

Dermatomal innervation of the limb

Question 74

In general, the higher spinal cord segments provide sensory innervation to the

Answer 74

Lateral side of the upper limb

Question 75

In general, the lower spinal cord segments provide sensory innervation to the

Answer 75

Medial side of the upper limb

Question 76

In general, pre-plexus nerve injuries (i.e. injuries to the spinal cord, spinal nerve, anterior rami or trunks) will result in

Answer 76

Dermatomal sensory losses and segmental muscular weakness

Question 77

Will result in cutaneous nerve sensory losses and muscle loss related to specific peripheral nerves (e.g. muscles innervated by the radial nerve, the median nerve, the ulnar nerve, etc.)

Answer 77

Post-plexus nerve injuries (injuries to terminal or collateral nerves)

Question 78

There are three nerves in the operative field during ALND that are susceptible to injury and deserve special note, what are they?

Answer 78

1. ) Long thoracic nerve 2. ) Thoracodorsal nerve 3. ) Intercostobrachial nerve

Question 79

Arises in the neck from branches of the anterior rami of cervical vertebrae C5, C6, and C7 and innervates the important serratus anterior muscle

Answer 79

Long thoracic nerve

Question 80

Injury to the long thoracic nerve may paralyze the serratus anterior. Patient would then have a hard time

Answer 80

Raising their hand (i.e. impaired upward rotation of the scapula

Question 81

Arises from the posterior cord of the brachial plexus, passes through the axilla, and descends on the posterior wall to innervate the latissimus dorsi muscle

Answer 81

Thoracodorsal nerve

Question 82

Arises as a branch of the second intercostal nerve. It crosses the axilla to reach the medial side of the arm, where it provides cutaneous sensory innervations

Answer 82

Intercostobrachial nerve

Question 83

Injury to the intercostobrachial nerve during ALND can result in

Answer 83

Chronic postoperative pain in region innervated

Question 84

The only bony connection to the axial skeleton

Answer 84

Sternoclavicular Joint

Question 85

Innervates proximal muscles: intrinsic shoulder muscles and axillary wall muscles

Answer 85

Brachial Plexus

Question 86

Paralysis of muscles innervated by same terminal nerve or collateral nerve

Answer 86

Post-plexus lesion (injury to infraclavicular portion of plexus)

Question 87

Weakness (paresis) of muscles of same segmental innervation

Answer 87

Pre-plexus lesion (Injury to supraclavicular portion)