Axilla

Question 1

What makes up the apex of the axilla?

Answer 1

Apex: cervico-axillary canal

-bounded by 1st rib, clavicle and superior border of scapula.

Question 2

What makes up the base of the axilla?

Answer 2

Base: formed by concave skin, subcutaneous tissue and axillary fascia extending from arm to thoracic wall.

• Forms axillary fossa (armpit)
• bounded by anterior and posterior axillary folds, thoracic wall and medal aspect of arm.

Question 3

What makes up the anterior wall of axilla?

Answer 3

Anterior wall: formedby pectoralis major/minor mm. and deep fascias.
-anterior axial fold: inferior most part of anterior wall that can be grasped which is formed by pectoralis major m. and overlying skin.

Question 4

What makes up the posterior wall of axilla?

Answer 4

Posterior wall: formed by scapula, subscapularis, trees major and latissimus dorsi mm.
-Posterior axial fold: inferior most part of posterior wall that may be grasped , extends further inferior than anterior wall, formed by latissimus corse and trees major mm. and skin.

Question 5

What makes up the medial wall of axilla?

Answer 5

Medial wall: formed by thoracic wall.

-1st-4th ribs and intercostal mm. and serratus anterior m.

Question 6

What makes up the lateral wall of axilla?

Answer 6

Lateral wall: formed by inter tubercular groove of humerus (narrow wall)

Question 7

What does the axilla contain?

Answer 7

contains:

• axillary blood vessels
• lymphatic vessels and nodes
• axillary fat
• cords and branchesof brachial plexus

Question 8

What is the axillary artery continuous with and what does it become?

Answer 8

Continuos with Subclavian a. and becomes brachial a.

Question 9

In the 1st part of the axillary artery what is branches off in this section?

Answer 9

• From lateral border of 1st rib to medial border of pectoralis minor m.
• Superior (supreme) thoracic a.

Question 10

What are the branches in the 2nd part of the axillary artery?

Answer 10

• Posterior to pectoralis minor
• Thoracoacromial trunk which was four branches-> clavicular, acormial deltoid, pectoral.
• Lateral thoracic a

Question 11

What are the branches of the 3rd part of the axillary artery?

Answer 11

• From lateral border of pectoralis minor to inferior border of teres major
• subscapular a.
• anterior humeral circumflex a.
• posterior humeral circumflex a. ->found in quadrangular space.

Question 12

Scapular anastomoses involves what arteries?

Answer 12

• Dorsal scapular a.
• Suprascapular a.
• Circumflex scapular a. (via subscapular a.)

Question 13

What is the key player in scapular anastomosis?

Answer 13

Circumflex scapular a.
-it is via its anastomoses with supra scapular, dorsal scapular and even intrecostal aa. that allow bloode flow to be reversed through the sub scapular a. thus reaching the 3rd part of the axillary a.

Question 14

The surgical ligation of the axillary a. between what two arteries will cut off blood supply to arm?

Answer 14

between subscapular a. and profunda brachii a.

Question 15

The axillary vein is formed by the union of….. and it occurs where?

Answer 15

Brachial vv. (venae comitatnates) and basilic v.

-occurs at inferior border of trees major m.

Question 16

The axillary vein ends at….. and becomes what?

Answer 16

Ends at lateral border of 1st rib and becomes subclavian v.

Question 17

What does the axillary vein receive?

Answer 17

Cephalic v.

Question 18

Where are the axillary lymph nodes (arranged in 5 groups)?

Answer 18

• Pectoral (anterior) nodes:lie along medal wall of axilla
• Subscapular (posterior) nodes: lie along posterior axillary fold
• Humeral (lateral) nodes: lie along lateral wall of axilla
• Central nodes: lie dep to pectoralis minor m.
• Apical nodes: located at apex of axilla

Question 19

Where do pectoral, subscapular, humeral, central and apical nodes receive lymph?

Answer 19

• Pectoral receive lymph mainly from anterior thoracic wall and scapular region
• Subscapular receive lymph from posterior thoracic wall and scapular region.
• Humeral receives nearly all lymph from upper limb
• Central receive lymph from the above 3 groups
• Apical receives lymph from all groups of axillary nodes as well as those accompanying cephalic v.

Question 20

Where does the brachial plexus begin and end?

Answer 20

Begins in neck and extends to axilla.

Question 21

What forms the union of brachial plexus…. VPR of?

Answer 21

VPR of C5-C8 and T1

-often C4 and T2 will contribute

Question 22

What do C5-C6 primarily innervate?

Answer 22

Primarily innervate mm. that act at shoulder or flex elbow.

Question 23

What do C7-8 innervate?

Answer 23

innervate mm. that extend elbow or are part of forearm

Question 24

What does T1 primarily innervate?

Answer 24

primarily innervates intrinsic mm. of hand

Question 25

Where do almost all branches of the brachial plexus arise?

Answer 25

Almost all branches arise in axilla

Question 26

Brachial Roots unite to form 3 trunks, what are they and what forms them?

Answer 26

• Superior trunk: formed by union of C5 and C6 (sometimes C4)
• Middle trunk: continuation of C7
• Inferior trunk: formed by union of C8 and T1 (sometimes T2)

Question 27

Where are the following located:

• roots and trunks
• Divisions
• Cords and branches

Answer 27

• Roots and trunks: are in the neck
• Divisions: are deep to the clavicle
• Cords and branches: are in the axilla