Pectoral Muscles & The Axilla Flashcards Preview

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Flashcards in Pectoral Muscles & The Axilla Deck (10):
0

What is the action of the pectoralis minor?
What are the attachments?
How is it innervated?

Stabilises scapula (it attaches to the coracoid process)
Medial pectoral nerves
O: 3rd-6th ribs
I: coracoid process

1

What is the action of the subclavius?
How is it innervated?

Anchors and depresses clavicle
Nerve to subclavius

2

What is the action of the serratus anterior?
How is it innervated?

Protracts and rotates scapula
Long thoracic nerve (nerve roots:c5,c6&c7)

3

What are the causes and consequences of damage to the long thoracic nerve?

May be injured by blows or pressure on the posterior triangle, trauma to the shoulder, Axillary clearance, repetitive movements involving the shoulder or by structures becoming inflamed and pressing on the nerve
The serratus anterior is paralysed
Inability to rotate the scapula when abducting the arm above 90 degrees

4

What happens in axillary clearance?

If breast cancer is confirmed, the axillary nodes need to be removed to prevent the cancer spreading. The is known as axillary clearance. (During this procedure, the long thoracic nerve may become damaged, resulting in winged scapula)

5

What is the action of the pectoralis major?
What are the attachments?
How is it innervated?

Adducts, flexes and medially rotates the humerus
Medial and lateral pectoral nerves
O: clavicle and sternum
I: intertubecular groove

6

The axilla is a passageway for the neurovascular structures supplying the upper limb. What are its borders?

Apex - at the top
Base - skin folds and subcutaneous tissue
Anterior - pec major and pec minor
Posterior - scapula covered by subscapularis
Medial - thoracic cage covered by serratus anterior
Lateral - inter-tubercular groove of the humerus

7

What are the contents of the axilla?

Axillary artery
axillary vein - formed by the union of the brachial and bascillic veins
axillary fat
Axillary lymph nodes - central, humeral, pectoral
Lymphatic vessels and the brachial plexus.
These neurovascular structures are embedded in the axillary sheath

8

Describe the anatomy of the axillary artery

Can be split in to three parts
Continues on from the subclavian artery, and continues as the brachial artery
The first part of the axillary artery is contained within the axillary sheath, it gives rise to one branch - superior thoracic artery
The second part of the axillary artery is posterior to pec minor - two branches: thoraco-acromial and lateral thoracic artery
The third branch of the axillary artery goes from pec minor to teres major - three branches: subscapular and anterior and posterior circumflex humeral

9

What are the causes and consequences of damage to the axillary nerve?

Anterior dislocation of the humerus, surgical neck fracture, IM deltoid injection
Paralysis of deltoid and teres minor - unable to abduct arm
Paralysis of the lateral cutaneous nerve of the arm - loss of sensation over the regimental badge area