Head and Neck: Lymphatics

Question 1

Describe the formation of tissue fluid

Answer 1

There is higher hydrostatic pressure in the arteriole than oncotic so fluid leaks out into the capillary bed
There is also a small amount of leakage of small proteins which are able to pass easily into the lymphatic capillaries because the pores are much bigger

Question 2

What are the components of lymph

Answer 2

• tissue fluid
• small proteins
• lipids (chylomicrons from gut lymphatics)
• damaged cells
  Pathological: bacteria, cancer cells (therefore a route for spread of infection and metastases)

Question 3

How much lymph is produced per day?

Answer 3

3-4 litres per day

Question 4

What are the features of the lymph nodes wrt the number of lymphatic vessels entering and leaving

Answer 4

Several afferent lymphatic vessels enter the node but only one efferent vessel leaves - this slows the flow

All lymph passes through at least 1 node

Question 5

What are the lymphatic ducts?

Answer 5

Ducts that drain the lymph into the subclavian veins

Right lymphatic duct: drains lymph from the right side of the head, right arm and upper right torso
Left (thoracic duct): drains lymph from rest of body

Question 6

Why does lymph drain into the venous system?

Answer 6

Drains into veins just before the heart as its the lowest pressure point

Question 7

Why does the lymphatic system flow unidirectionally?

Answer 7

There is passive constriction from constriction of muscles surrounding the vessels
There is also intrinsic constriction from smooth muscle in the wall of the vessels
The vessels have valves

Question 8

What is lymphoedema?

Answer 8

Abnormal collection of protein-rich fluid causing tissue swelling
It is due to a compromised lymphatic system (very different to oedema seen in heart failure)

Question 9

What can cause lymphoedema?

Answer 9

• removal of lymph nodes
• infections eg certain parasites
• damage to the lymphatic system eg cancer
• lack of limb movement (muscle contraction aids movement of lymph fluid)
• can be congenital but this is rare

Question 10

What is the structure of a lymph node?

What cells do they contain?

Answer 10

Has a tough fibrous outer capsule with regular connective tissue inside (texture of candy floss so big things can get stuck)
Contains lots of B and T lymphocytes and macrophages

Question 11

What makes the neck nodes superficial or deep?

Answer 11

Whether they are within the investing layer of the deep cervical fascia (deep)

Question 12

Name the superficial lymph nodes of the neck

Answer 12

Submental 
Submandibular 
Pre-auricular 
Post-auricular 
Occipital 
Superficial cervical 
Posterior cervical
Anterior cervical

Question 13

Name the deep lymph nodes of the neck

Answer 13

Jugulo-digastric
Jugulo-omohyoid
Supraclavicular

Question 14

What is Virchow’s node?

Answer 14

The left supraclavicular node

Can be enlarged in thoracic and abdominal malignancies

Question 15

Which node is enlarged in tonsillitis?

Answer 15

The jugulo-digastric

Question 16

Which node would be enlarged if there was infection of the skin of the neck?

Answer 16

Ant and post and superficial cervical lymph nodes

Question 17

Which node would be enlarged if there was infection of the lower lip, chin, tip of tongue?

Answer 17

Submental

Question 18

Which node would be enlarged if there was infection of the upper lip and teeth, most of face, nasal cavity and middle tongue?

Answer 18

Submandibular

Question 19

Which node would be enlarged if there was infection of the scalp, anterior ear or parotid gland?

Answer 19

Pre-auricular

Question 20

Which node would be enlarged if there was infection of the scalp, posterior ear or ear canal?

Answer 20

Post-auricular (mastoid region)

Question 21

Which node would be enlarged if there was infection of the back of the head and neck?

Answer 21

Occipital