Session 2 The Axilla

Question 0

Describe the axillary artery

Answer 0

Continuation of subclavian artery - begins at lateral border of 1st rib and ends at inferior border of teres major (becomes brachial artery h.
It is divided into 3 parts:
1) located between lateral border of 1st rib and medial border of pec minor,enclosed in the axillary sheath and has 1 branch - superior thoracic artery (arises just inferior to the Subclavius)
2) 2nd part lies posterior to Pectoralis minor and had two branches - thoraco-Acromial and lateral thoracic arteries which pass medial and lateral to the muscle respectively.
3) 3rd part extends from lateral border of Pectoralis minor to inferior border of Pectoralis major. Three branches: subscapular, anterior and posterior circumflex humeral arteries. The circumflex arteries have a common trunk.

Question 1

What does the Axilla contain?

Answer 1

Axillary blood vessels, lymphatic vessels and groups of axillary lymph nodes (all embedded in axillary fat) and brachial plexus,
Proximally these neurovascular structurs are ensheathed in a nerve-like extension of the cervical fascia (axillary sheath)

Question 2

Describe the axillary vein

Answer 2

Formed by the union of the brachial vein and the basilic vein at the inferior border of the teres major. Basilic vein parallels the brachial artery to the axilla where it merges sigh the accompanying veins of the axillary artery to form the axillary vein.
3 parts (3,2,1) which correspond to axillary artery (1,2,3)
Ends at the lateral border of the 1st rib where it becomes the subclavian vein.
The axillary vein receives the thoraco-epigastric vein(s) which are formed by the anastomoses of the superficial veins from the inguinal region with tributaries of the axillary vein (usually the lateral thoracic vein). These veins constitute a collateral route that enables venous return in the obstruction of the inferior vena cava,

Question 3

Describe the Axillary Lymph Nodes

Answer 3

Fibrocartilage connective tissue of the axilla (axillary fat) contains many lymph nodes which are arranged in five principal groups: Pectoral, Subscapular, Humeral, Central and Apical
These efferent vessels ultimately unite to form the subclavian lymphatic trunk although some vessels may drain en route through the Clavicular nodes.

Question 4

Describe Lymphangitis in the Upper Limb (Enlargement of the axillary lymph nodes)

Answer 4

An infection could cause the axillary nodes to enlarge and become tender and inflamed.
Characterised by the development of warm, red, tender, streaks in the skin of the limb.
Infections in the pectoral region and breast including the superior part of the abdomen can also produce enlargement of the axillary nodes,
In metastatic cancer of the apical group of axillary lymph nodes,the nodes often adhere to the axillary vein which may necessitate excision of part of this vessel.
Enlargement of the apical nodes may obstruct the cephalic vein superior to the pec minor.

Question 5

Describe Axillary Clearance

Answer 5

Excision and pathological analysis of axillary lymph nodes are often necessary for staging and determining the appropriate treatment of a cance.
Lymphatic drainage of the upper limb may be impeded after the removal of axillary nodes resulting in lymphedema, swelling as a result of accumulated lymph especially in the subcutaneous tissue

Question 6

During axillary node dissection (removal), what two nerves are at risk of injury?

Answer 6

Long thoracic nerve --> winged scapula
Thoracodorsal nerve (supplies Latissimus dorsi) - weakens medial rotation and Adduction. If the nodes around this nerve are obviously malignant, sometimes the nerve has to be sacrificed to increase the likelihood of complete removal of all malignant cells. The person is unable to raise the trunk with the upper limbs as occurs during climbing.

Question 7

Which parts of the brachial plexus are at most risk to injury as a result of this fracture i.e. which parts lie immediately posterior to the usual fracture point of the clavicle?

Answer 7

The anterior and posterior divisions:
3 anterior divisions (superior, middle and inferior)
3 posterior divisions (lateral, posterior and medial)