Upper Limb - Axilla (1)

Question 1

What is the name for the apex of the axilla? What are the bony boundaries?

Answer 1

Cervicoaxillary canal. Bounded by the 1st rib, the clavicle, and the superior border of the scapula.

Question 2

What is the anterior axillary fold?

Answer 2

This is the anterior boundary of the base of the axilla. It can be grasped between the fingers. It is formed by the pectoralis major muscle, as it bridges from thoracic wall to humerus, and the overlying integument.

Question 3

What is the posterior axillary fold?

Answer 3

This is the posterior boundary of the base of the axilla. It can be grasped between the fingers. It is formed by the latissimus dorsi and the teres major, as they bridge from the back to the humerus, and the overlying integument.

Question 4

What forms the base of the axilla?

Answer 4

The deep axillary fascia, bridging from the clavipectoral fascia (of pectoralis muscles), to join the fascia of latissimus dorsi. It forms concave skin. The anterior border is the anterior axillary fold, and the posterior border is the posterior axillary fold.

Question 5

What forms the medial wall of the axilla?

Answer 5

The thoracic wall of 1st-4th ribs and intercostal muscles, and the overlying serratus anterior.

Question 6

What forms the lateral wall of the axilla?

Answer 6

This is a narrow bony wall formed by the intertubercular groove of the humerus.

Question 7

What forms the anterior wall of the axilla?

Answer 7

Pectoralis minor and Pectoralis major, with their clavicopectoral fascia, extending down to the anterior axillary fold.

Question 8

What forms the posterior wall of the axilla?

Answer 8

Mostly subscapularis, extending down to latissimus dorsi and the posterior axillary fold.

Question 9

What is the axillary sheath, and what does it contain?

Answer 9

This is a sleeve-like extension of the cervical fascia. It contains a neurovascular bundle made up of the brachial plexus, the axillary artery and the axillary vein.

Question 10

Where does the axillary artery come from?

Answer 10

It is an extension of the right subclavian artery, and starts being named so as it enters the cervicoaxillary canal.

Question 11

What marks the distal end of the axillary artery?

Answer 11

The inferior border of teres major, at which point it has reached the humerus and is now called the brachial artery.

Question 12

The second part of the axillary artery travels beneath which muscle?

Answer 12

Pectoralis minor (near its attachment to the coracoid process of the scapula).

Question 13

Name two branches that come off the third part of the axillary artery.

Answer 13

Subscapular artery. Anterior and posterior circumflex humeral arteries.

Question 14

Which part of the humerus is encircled by the circumflex humeral arteries?

Answer 14

The surgical neck of the humerus.

Question 15

Which veins converge to form the axillary vein?

Answer 15

Brachial veins (surrounding the axillary artery) and Basilic vein. After they have converged and formed the axillary vein, the Cephalic vein drains into this terminal part of the axillary vein.

Question 16

Into which vein does the axillary vein drain?

Answer 16

Subclavian vein.

Question 17

At which bony landmark does the axillary vein become the subclavian vein?

Answer 17

1st rib.

Question 18

What are the five groups of axillary lymph nodes?

Answer 18

Pectoral (anterior), Subscapular (posterior), Humeral (lateral), Central, Apical.

Question 19

What is the typical drainage pattern between the five groups of axillary lymph nodes?

Answer 19

Pectoral, Subscapular and Humeral nodes all drain into the Central nodes, which drain into the Apical nodes.

Question 20

Which axillary lymph nodes receive lymph from the anterior thoracic wall?

Answer 20

Pectoral

Question 21

Which axillary lymph nodes receive lymph from the posterior thoracic wall and scapular region?

Answer 21

Subscapular

Question 22

To which axillary lymph nodes does most of the lymph from the upper limb drain? Where does the remainder drain to?

Answer 22

Mostly to the humeral (lateral) nodes, except for the lymphatic vessels surrounding the cephalic vein, which drain into the apical axillary nodes.

Question 23

What is important about the anatomy of the suprascapular artery and the subscapular artery?

Answer 23

These arteries anastomose (as do many arteries around the scapula), and so there is collateral supply available when a section of the axillary artery is ligated.