Axilla & Brachial plexus part 1

Question 1

• All major structures passing into and out of upper limb pass through_________________

Answer 1

Axilla

Question 2

Describe the shape of the axilla

Answer 2

Irregularly shaped pyramidal space
- Inlet
- Four sides
- Floor (Base)

Question 3

The axilla is formed by:

Answer 3

-Clavicle, scapula and humerus
- Upper thoracic wall
- Related muscles

Question 4

What is the position of the apex of the axilla?

Answer 4

• Near medial aspect of coracoid process. It is directed laterally

Question 5

Describe the margins of the axillary inlet

Answer 5

Margins completely formed by bone:
- Medial margin: Lateral border of first rib
- Anterior margin: Posterior surface of clavicle
- Posterior margin: Superior border of scapula up to
coracoid process

Question 6

Major vessels and nerves pass between neck and axilla by_______________________

Answer 6

crossing over lateral border of first rib and through axillary
inlet

Question 7

What is the transition point where the subclavian artery becomes the axillary artery?

Answer 7

As is crosses the Lateral margin of 1st rib and enters the axilla

Question 8

What is the transition point where the axillary vein becomes the subclavian vein?

Answer 8

Axillary vein becomes subclavian vein as it passes over
lateral margin of first rib and exits axilla

Question 9

Artery and vein separated by insertion of __________________ as they pass over first rib

Answer 9

Anterior scalene muscle

Question 10

Where is the Inferior trunk of brachial plexus, subclavian artery and
subclavian vein located? i

Answer 10

They lie directly on the first rib.

Question 11

Name the muscles that make up the anterior wall of the axilla

Answer 11

Pectoralis major and minor, subclavius
AND Clavipectoral fascia

Question 12

What is the anterior axillary fold?

Answer 12

Fold of skin
- Anteroinferior border of axilla
- Inferior margin of pectoralis major muscle lies underneath

Question 13

Describe the clavipectoral fascia

Answer 13

Thick sheet of connective tissue
* Connects clavicle to floor of axilla
* Encloses subclavius and pectoralis minor muscles
- Spans gap between muscles

Question 14

What structures pass between clavipectoral fascia and pec MINOR?

Answer 14

Cephalic vein, thoraco-acromial artery, and lateral pectoral
nerve

Question 15

The __________________________ leaves axilla by passing through
fascia inferior to pectoralis minor muscle

Answer 15

Long thoracic artery

Question 16

The __________________ Leaves axilla by penetrating
pectoralis minor muscle and fascia (Branches occasionally
pass around lower margin of muscle and through fascia)

Answer 16

medial pectoral nerve

Question 17

What consists of the medial wall?

Answer 17

-It consists of the upper thoracic wall ( ribs and related intercostal muscles)
-serratus anterior muscles

Question 18

Describe the intercostobrachial nerve

Answer 18

Lateral cutaneous branch of 2nd intercostal nerve
- Passes directly through wall and into axilla
- Communicates with medial cutaneous nerve of arm in
axilla and supplies skin on upper posteromedial side of arm

Question 19

What makes up the lateral wall?

Answer 19

Narrow
• Formed entirely by intertubercular sulcus of humerus

Question 20

What makes up the posterior wall?

Answer 20

Bony framework formed by costal surface of scapula.

Subscapularis
Teres major
Lattisimus dorsi
Long head of the triceps brachii

Question 21

What is the posterior axillary fold?

Answer 21

Fold of skin
- Posteroinferior border of axilla
- Terminal part of teres major muscle and tendon of
latissimus dorsi muscle lie underneath

Question 22

T or F:

Anterior axillary fold is more inferior than posterior fold

Answer 22

False. It is more superior

Question 23

What is the significance of the gaps in between muscles?

Answer 23

Allow structures to pass between axilla, posterior scapular
and deltoid regions and posterior compartment of arm

Question 24

What passes on the quandrangular space?

Answer 24

Passageway between axilla and posterior scapular & deltoid regions.

Axillary nerve
- Posterior circumflex humeral artery - Posterior circumflex humeral vein

Question 25

Boundaries of the Quadrangular space

Answer 25

Inferior margin of subscapularis muscle
- Surgical neck of humerus
- Superior margin of teres major muscle
- Lateral margin of long head of triceps brachii muscle

Question 26

What passes on the triangular space?

Answer 26

Passageway between axilla and posterior scapular region

• Circumflex scapular artery
• Circumflex scapular vein

Question 27

Boundaries of the triangular space

Answer 27

Medial margin of long head of triceps brachii muscle - Superior margin of teres major muscle
- Inferior margin of subscapularis muscle

Question 28

What passes on the triangular interval?

Answer 28

Passageway between axilla and posterior compartment

• Radial nerve
• Profunda brachii artery

Question 29

Boundaries of the triangular interval?

Answer 29

Lateral margin of long head of triceps brachii muscle
- Shaft of humerus
- Inferior margin of teres major muscle

Question 30

Describe the floor of the axilla

Answer 30

Formed by fascia and a dome of skin
- Spans distance between inferior margins of walls
Supported by clavipectoral fascia
Structures enter and exit axilla immediately lateral to floor - Convergence of anterior and posterior walls
- Continuation of axilla with anterior compartment of arm

Question 31

What makes the floor of axilla?

Answer 31

Clavipectorialis fascia