Lymphatic Drainage of the Thorax

Question 1

How many lymph nodes are there in humans?

Answer 1

600-700

Question 2

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

Answer 2

Right upper quadrant drains into the right subclavian vein.

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

Question 3

What is the size of a normal lymph node?

Answer 3

<2.5 cm

Question 4

What is a common cause of lymphadenopathy?

Answer 4

Infection

Question 5

What is lymph usually like?

Answer 5

Colourless and odourless

Question 6

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

Answer 6

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

It is called chyle

Question 7

What causes movement of lymph through the vessels?

Answer 7

Skeletal muscle contraction

Pulses in arteries

Question 8

What prevents backflow in the vessels?

Answer 8

Valves

Question 9

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

Answer 9

Parasternal (associated with internal thoracic arteries)

Intercostal

Diaphragmatic

Question 10

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

Answer 10

Parasternal - bronchomediastinal trunk

Upper intercostal - bronchomediastinal trunk

Lower intercostal - thoracic duct

Diaphragmatic - brachiocephalic nodes + aortic/lumbar part of the thoracic duct

Superficial - axillary and parasternal nodes

Question 11

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

Answer 11

It begins with the cysterna chyli - L2

Question 12

Describe the path of ascension of the thoracic duct.

Answer 12

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 13

Where do the lymphatics in the lungs drain to?

Answer 13

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

Question 14

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

Answer 14

Tracheobronchial lymph vessels join the parasternal and brachiocephalic lymph vessels to form the BRONCHOMEDIASTINAL trunk

Question 15

Describe the lymphatic drainage of the heart.

Answer 15

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

Tracheobronchial nodes

Brachiocephalic nodes

Question 16

What do the nodes on the aorta receive lymph from?

Answer 16

Oesophagus, diaphragm, pericardium and liver

Question 17

Where do these nodes drain to?

Answer 17

Thoracic duct and posterior mediastinal nodes