Axilla & Brachial plexus part 1 Flashcards
- All major structures passing into and out of upper limb pass through_________________
Axilla
Describe the shape of the axilla
Irregularly shaped pyramidal space
- Inlet
- Four sides
- Floor (Base)
The axilla is formed by:
-Clavicle, scapula and humerus
- Upper thoracic wall
- Related muscles
What is the position of the apex of the axilla?
- Near medial aspect of coracoid process. It is directed laterally
Describe the margins of the axillary inlet
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
Major vessels and nerves pass between neck and axilla by_______________________
crossing over lateral border of first rib and through axillary
inlet
What is the transition point where the subclavian artery becomes the axillary artery?
As is crosses the Lateral margin of 1st rib and enters the axilla
What is the transition point where the axillary vein becomes the subclavian vein?
Axillary vein becomes subclavian vein as it passes over
lateral margin of first rib and exits axilla
Artery and vein separated by insertion of __________________ as they pass over first rib
Anterior scalene muscle
Where is the Inferior trunk of brachial plexus, subclavian artery and
subclavian vein located? i
They lie directly on the first rib.
Name the muscles that make up the anterior wall of the axilla
Pectoralis major and minor, subclavius
AND Clavipectoral fascia
What is the anterior axillary fold?
Fold of skin
- Anteroinferior border of axilla
- Inferior margin of pectoralis major muscle lies underneath
Describe the clavipectoral fascia
Thick sheet of connective tissue
* Connects clavicle to floor of axilla
* Encloses subclavius and pectoralis minor muscles
- Spans gap between muscles
What structures pass between clavipectoral fascia and pec MINOR?
Cephalic vein, thoraco-acromial artery, and lateral pectoral
nerve
The __________________________ leaves axilla by passing through
fascia inferior to pectoralis minor muscle
Long thoracic artery
The __________________ Leaves axilla by penetrating
pectoralis minor muscle and fascia (Branches occasionally
pass around lower margin of muscle and through fascia)
medial pectoral nerve
What consists of the medial wall?
-It consists of the upper thoracic wall ( ribs and related intercostal muscles)
-serratus anterior muscles
Describe the intercostobrachial nerve
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
What makes up the lateral wall?
Narrow
• Formed entirely by intertubercular sulcus of humerus
What makes up the posterior wall?
Bony framework formed by costal surface of scapula.
Subscapularis
Teres major
Lattisimus dorsi
Long head of the triceps brachii
What is the posterior axillary fold?
Fold of skin
- Posteroinferior border of axilla
- Terminal part of teres major muscle and tendon of
latissimus dorsi muscle lie underneath
T or F:
Anterior axillary fold is more inferior than posterior fold
False. It is more superior
What is the significance of the gaps in between muscles?
Allow structures to pass between axilla, posterior scapular
and deltoid regions and posterior compartment of arm
What passes on the quandrangular space?
Passageway between axilla and posterior scapular & deltoid regions.
Axillary nerve
- Posterior circumflex humeral artery - Posterior circumflex humeral vein
Boundaries of the Quadrangular space
Inferior margin of subscapularis muscle
- Surgical neck of humerus
- Superior margin of teres major muscle
- Lateral margin of long head of triceps brachii muscle
What passes on the triangular space?
Passageway between axilla and posterior scapular region
- Circumflex scapular artery
- Circumflex scapular vein
Boundaries of the triangular space
Medial margin of long head of triceps brachii muscle - Superior margin of teres major muscle
- Inferior margin of subscapularis muscle
What passes on the triangular interval?
Passageway between axilla and posterior compartment
- Radial nerve
- Profunda brachii artery
Boundaries of the triangular interval?
Lateral margin of long head of triceps brachii muscle
- Shaft of humerus
- Inferior margin of teres major muscle
Describe the floor of the axilla
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
What makes the floor of axilla?
Clavipectorialis fascia
