Axilla

Question 1

What is the axilla?

Answer 1

The name given to an area that lies underneath the glenohumeral joint, at the junction of the upper limb and thorax

Question 2

What is the function of the axilla?

Answer 2

It’s a passageway by which structures such as vessels and nerves can enter and leave the upper limb

Question 3

What is the overall 3D shape of the axilla?

Answer 3

Looks slightly like a pyramid

Question 4

What do the borders of the axilla consist of?

Answer 4

Four sides, and a base with an opening at the apex

Question 5

What are the walls of the axilla?

Answer 5

Apex
 Lateral wall
 Medial wall
 Anterior wall
 Posterior wall

Question 6

What is the apex of the axilla also known as?

Answer 6

The axillary inlet

Question 7

What forms the apex of the axilla?

Answer 7

The lateral border of the first rib, superior border of the scapula, and the posterior border of the clavicle

Question 8

What forms the lateral wall of the axilla?

Answer 8

The intertubecular groove of the humerus

Question 9

What forms the medial wall of the axilla?

Answer 9

The serratus anterior and thoracic wall (ribs and intercostal muscles)

Question 10

What forms the anterior wall of the axilla?

Answer 10

Pectoralis major and underlying pectoralis minor and subclavius muscles

Question 11

What forms the posterior wall of the axilla?

Answer 11

Subscapularis, teres major, latissimus dorsi

Question 12

How does the size and shape of the axilla vary?

Answer 12

With arm abuductio

Question 13

When does the size of the axilla decrease most markedly?

Answer 13

When the arm is fully abducted

Question 14

What is true of the axilla when the arm is fully abducted?

Answer 14

The contents of the axilla are at most risk of injury

Question 15

How many routes are there by which structures leave the axilla?

Answer 15

Three

Question 16

What is the main route of exit from the axilla?

Answer 16

Immediately inferiorly and laterally, into the upper limb

Question 17

What are the other routes of exit from the axilla?

Answer 17

Via the quadrangular space

Via the clavipectoral triangle

Question 18

What is the quadrangular space?

Answer 18

A gap in the posterior wall of the axilla

Question 19

What does the quadrangular space allow?

Answer 19

Access to the posterior arm and shoulder

Question 20

What structures pass through the quadrangular space?

Answer 20

Axillary nerve

Posterior circumflex humeral artery

Question 21

What is the clavipectoral triangle?

Answer 21

An opening in the anterior wall of the axilla

Question 22

What is the clavipectoral triangle bound by?

Answer 22

The pectoralis major, deltoid and clavicle

Question 23

What travels through the clavipectoral triangle?

Answer 23

The cephalic vein enters the axilla

The medial and lateral pectoral nerves leave the axilla

Question 24

What are the clinically important contents of the axilla region?

Answer 24

Axillary artery Axillary vein
Brachial plexus
Biceps brachii and coracobrachialis tendons
Axillary lymph nodes

Question 25

What is the axillary artery?

Answer 25

The main artery supplying the upper limb

Question 26

What is the axillary artery commonly referred to having?

Answer 26

Three parts, one medial to the pectoralis minor, one posterior to the pectoralis minor, and one lateral to the pectoralis minor

Question 27

What parts of the axillary artery travel in the axilla?

Answer 27

The medial and posterior parts

Question 28

What is the axillary vein?

Answer 28

The main vein draining the upper limb

Question 29

What are the axillary veins largest tributaries?

Answer 29

The cephalic and basilic veins

Question 30

What is the brachial plexus?

Answer 30

A collection of spinal nerves that form peripheral nerves of the upper limb

Question 31

What happens to the biceps brachii and coracobrachialis tendons when they move through the axilla?

Answer 31

They attach to the coracoid process of the scapula

Question 32

What do the axillary lymph nodes do?

Answer 32

Filter lymph that has drained from the upper limb and pectoral region

Question 33

What does axillary lymph node enlargement mean in women?

Answer 33

It is a non-specific indicator of breast cancer

Question 34

What is the apex of the axilla?

Answer 34

An opening between the clavicle, first rib and the scapula

Question 35

What can happen in the apex of the axilla?

Answer 35

The vessels and nerves may become compressed between the bones, called thoracic outlet syndrome

Question 36

What are the common causes of TOS?

Answer 36

Trauma, e.g. fractured clavicle  | Repetitive movements

Question 37

How does TOS often present?

Answer 37

Pain in the affected limb, tingling, muscle weakness and discolouration

Question 38

What does where the pain in TOS is felt depend on?

Answer 38

What nerves are affected

Question 39

Why can lymph nodes be biopsied if breast cancer is suspected?

Answer 39

Approx. 75% of lymph from the breast drains into the axilla lymph nodes

Question 40

What may happen if breast cancer is confirmed?

Answer 40

The axillary nodes may need to be removed to prevent the cancer spreading, a procedure called axillary clearance

Question 41

What may happen during axillary clearance?

Answer 41

The long thoracic nerve may become damaged, resulting in winged scapula