Axilla and Brachial Plexus

Question 1

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

Answer 1

axilla

Question 2

The lymph nodes of the axilla receive drainage from:

Answer 2

• back
• neck
• upper limb
• anterior chest wall (including the breast)

Question 3

The shoulder girdle consists of:

Answer 3

• scapula and clavicle
• no joint connection to the back; only muscle

Question 4

Muscles that connect the shoulder girdle to the back:

Answer 4

• levator scapulae
• trapezius
• rhomboids
• latissimus dorsi

Question 5

What is the only joint connecting the should girdle/upper limb to the axial skeleton?

Answer 5

sternoclavicular joint

Question 6

Label:

Answer 6

• left: head of humerus
• right: glenoid fossa

Question 7

Label:

Answer 7

glenohumeral joint

• between head of humerus and glenoid fossa of the scapula.

Question 8

The four walls of the axilla:

Answer 8

• posterior (back)
• lateral (side)
• anterior (front)
• medial (bottom)

Question 9

Composition of the Lateral Wall of the axilla:

Answer 9

Humerus (bicipital groove)

• where the anterior and posterior walls converge

Question 10

Composition of the Anterior Wall of the axilla:

Answer 10

• Pectoralis Major
• Pectoralis Minor

Question 11

Composition of the Medial Wall of the axilla:

Answer 11

• Serratus Anterior

Question 12

Composition of the Posterior Wall of the axilla:

Answer 12

• Subcapularis
• Teres major
• Latissimus Dorsi

Question 13

Axillary Arteries Diagram:

Answer 13

Question 14

Label:

Answer 14

Question 15

Three cords of the brachial plexus run through the axilla and surround the axillary artery. What are the three cords?

Answer 15

• lateral
• medial
• posterior

Question 16

Axillary sheath:

Answer 16

• connective tissue that surrounds the axillary artery and brachial plexus cords.
• axillary vein is not contained in the axillary sheath.

Question 17

An aneurysm of the axillary artery can cause:

Answer 17

• compression of the brachial plexus cords due to their containment in the axillary sheath.

Question 18

A nerve plexus is:

Answer 18

• 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.

Question 19

The multiple sources of nerve fibers in the brachial plexus are:

Answer 19

• anterior rami of C5, C6, C7, C8, and T1

Question 20

The lateral and medial cords of the brachial plexus contain only _______ nerve fibers.

Answer 20

• anterior division

Question 21

The posterior cord of the brachial plexus contains only _________ nerve fibers.

Answer 21

• posterior division

Question 22

What terminal nerves of the brachial plexus contain only anterior division fibers?

Answer 22

• musculocutaneous, median, and ulnar nerves

Question 23

What terminal nerves of the brachial plexus contain only posterior division fibers?

Answer 23

• radial and axillary nerves

Question 24

What are the collateral nerves of the brachial plexus?

Answer 24

• long thoracic nerve
• dorsal scapular and suprascapular nerves
• three subscapular nerves (from posterior cord)
• lateral and medial pectoral nerves (from lateral and medial cords)

Question 25

The three subscapular nerves of the brachial plexus innervate:

Answer 25

* muscles that form the posterior wall of the axilla

Question 26

The lateral and medial pectoral nerves of the brachial plexus innervate:

Answer 26

* muscles that form the anterior wall of the axilla

Question 27

The long thoracic nerve of the brachial plexus innervates:

Answer 27

* muscle on the medial wall of the axilla.

Question 28

The dorsal scapular and suprascapular nerves of the brachial plexus innervate:

Answer 28

muscles of the shoulder girdle.

Question 29

The musculocutaneous nerve of the brachial plexus innervates:

Answer 29

* all muscles of anterior arm.

Question 30

The median nerve of the brachial plexus innervates:

Answer 30

* most muscles of anterior forearm (except 1.5) * remaining muscles innervated by ulnar nerve

Question 31

The ulnar nerve of the brachial plexus innervates:

Answer 31

* most muscles of anterior hand (except 5) * remaining muscles innervated by median nerve

Question 32

The radial nerve of the brachial plexus innervates:

Answer 32

* all muscles of posterior arm and forearm.

Question 33

The axillary nerve of the brachial plexus innervates:

Answer 33

* only two muscles: deltoid and teres minor.

Question 34

The collateral nerves of the brachial plexus innervate:

Answer 34

* proximal muscles of shoulder and axillary walls

Question 35

Segmental innervation of the muscles of the upper limb has what kind of gradient?

Answer 35

* "proximo-distal gradient" * more proximal muscles innervated by higher spinal cord segments. * more distal muscles innervated by lower spinal cord segments.

Question 36

The median nerve contains nerve fibers from C6 to T1, and innervates the anterior muscles of the forearm. What is the segmental innervation?

Answer 36

* proximal forearm: C6 and C7 * distal forearm: C7 and C8 * hand muscles: C8 and T1

Question 37

In general, higher spinal cord segments provide sensory innervation to the ______ side of the upper limb.

Answer 37

lateral side

Question 38

In general, lower spinal cord segments provide sensory innervation to the ______ side of the upper limb.

Answer 38

medial side

Question 39

In general, pre-plexus nerve injuries (i.e. SUPRACLAVICULAR) will result in:

Answer 39

* dermatomal sensory losses and segmental muscular weakness.

Question 40

In general, post-plexus nerve injuries (i.e. INFRACLAVICULAR) will result in:

Answer 40

* cutaneous nerve sensory losses and muscle paralysis related to specific terminal/collateral nerves.

Question 41

The long thoracic nerve (LTN) innervates what muscle?

Answer 41

* serratus anterior muscle. * injury leads to “winged-scapula”.

Question 42

The thoracodorsal nerve predecesor and innervation:

Answer 42

* arises from posterior cord of the brachial plexus * innervates latissimus dorsi (attaches to humeral head) * injury results in deficits in arm movement

Question 43

Label dermatomes:

Answer 43

Question 44

Label dermatomes:

Answer 44

Question 45

Label nerves:

Answer 45