Lymphatic drainage of the thorax

Question 1

Why do we have a lymphatic system?

Answer 1

• More fluid leaves blood capillaries than returns to them
• Uncompensated fluid movement from blood to the extracellular fluid would result in oedema and loss of blood volume
• Lymphatic vessels drain excess extracellular fluid back into the blood
• Ensure foreign particles come into contact with immune system

Question 2

what is the lymphatic system?

Answer 2

• Network of tissues and organs consisting of lymph vessels, lymph nodes and lymph
• Includes tonsils, adenoids, spleen and thymus
• 600-700 lymph nodes in humans
• Filter the lymph before it returns to the circulatory system

Question 3

How many lymph nodes are there in humans?

Answer 3

600-700

Question 4

what does the lymph trunk and lymph node contain?

Answer 4

Lymph trunk = carry the fluid
Lymph node= have expansions that do some of the filtering

Trunks= channel
Nodes= enlargements

Question 5

Describe the arrangement of the lymphatics across the body. State where the lymphatics join the venous circulation.

Answer 5

Right upper quadrant drains into the right subclavian vein.

Other three quadrants all drain via the thoracic duct into the left subclavian vein.

Question 6

What is the size of a normal lymph node?

Answer 6

<2.5 cm

Question 7

where are lymph nodes found and what do they contain?

Answer 7

• Found along lymph vessels
• contain lymphocytes and macrophages
• can act upon foreign bodies in the lymph
• drainage from infected regions detectable in enlarged lymph nodes
• found in armpit, groin, neck

Question 8

What is a common cause of lymphadenopathy?

Answer 8

Infection

Question 9

What is lymph usually like?

Answer 9

Colourless and odourless

Question 10

where is the lymph node usually enlarged in children?

Answer 10

It is usually enlarged in the neck in children due to the large number of respiratory infections

Question 11

How is lymph from the small intestines different? What is it called?

Answer 11

It is opaque and milky due to absorption of fats (chylomicrons)
It is called chyle

Question 12

how does the lymph move?

Answer 12

-no pumps exist
-moves by the action of others
Slow and sporadic – no “pump”
Maintained by action of adjacent structures
Skeletal muscles and the pulses in arteries
Unidirectional due to the presence of valves

Question 13

What causes movement of lymph through the vessels?

Answer 13

Skeletal muscle contraction

Pulses in arteries

Question 14

What prevents backflow in the vessels?

Answer 14

Valves

Question 15

What three groups of lymph nodes does the thoracic wall drain to?

Answer 15

The ones that drain the anterior chest wall--- Parasternal node (inside the chest wall)
Lymph drains into nodes associated with:
internal thoracic arteries (parasternal)
ribs (intercostal)
diaphragm (diaphragmatic)

REMEMBER: lymph nodes are going upwards towards the neck.

Question 16

Which larger lymph vessels do these three groups of nodes drain to?

Answer 16

Parasternal
-Bronchomediastinal trunks

Intercostal (upper)
-Bronchomediastinal trunks

Intercostal (lower)
-Thoracic duct

Diaphragmattic

• Brachiocephalic
• Aortic/lumbar

Superficial
-Axillary or parasternal

Question 17

Where does the thoracic duct start? State the vertebral level.

Answer 17

It begins at the cysterna chyli - L2 begins at vertebral level

It is the main channel draining most of the body

Question 18

Describe the path of ascension of the thoracic duct.

Answer 18

The thoracic duct ascends just to the right of midline, in between the aorta and the azygos vein. It crosses over to the left side at T5 and it then empties into the left subclavian vein.

Question 19

Where do the lymphatics in the lungs drain to?

Answer 19

Tracheobronchial nodes - this is the largest collection of lymph nodes in the body

Question 20

where does the thoracic duct empty?

Answer 20

-Empties into junction of left internal jugular and left subclavian vein

Question 21

What do the tracheobronchial lymph vessels join with and what does this form and where are they ?

Answer 21

Tracheobronchial lymph vessels join the parasternal and brachiocephalic lymph vessels to form the BRONCHOMEDIASTINAL trunk. They are located around bronchi and trachea, from within lung through hilum.

Question 22

Describe the lymphatic drainage of the heart.

Answer 22

Lymphatic drainage of the heart follows the coronary arteries and drains into the:
Tracheobronchial nodes
Brachiocephalic nodes

Question 23

What do the nodes on the aorta receive lymph from?

Answer 23

Oesophagus, diaphragm, pericardium and liver

Question 24

Where do these aortic nodes drain to?

Answer 24

Thoracic duct and posterior mediastinal nodes