Lecture 7 - Lymphatic drainage of the breast

Question 1

What level does the breast extend over?

Answer 1

Extends from the 2nd to the 6th rib along the midclavicular line.

Question 2

What muscle does the breast overlie?

Answer 2

Pectoralis major.

Question 3

What is the breast made up of?

Answer 3

Glandular tissue, fat and fibrous tissue.

Question 4

How does the tissue distribution change in pregnant women?

Answer 4

In non-lactating women, the predominant component of the breast is fat however in pregnant women, glandular tissue is more prominent.

Question 5

What is the structure of the breast?

Answer 5

• 15-20 ductal lobar units that drain into one main duct
• 4-18 milk ducts, culminating at one nipple/areola
• Fat is interdispersed between the ducts

Question 6

Describe the blood supply to the breast.

Answer 6

Rich blood supply delivered to pectoral region by several branches of these arteries:

• Lateral thoracic artery
• Internal thoracic artery
• Thoraco-acromial artery
• Thoraco-dorsal artery
• Intercostal arteries

Question 7

Describe the nerve supply to the breast.

Answer 7

• Sensory innervation from anteromedial branches (T3-5)
• Some innervation by supraclavicular nerves (upper and lateral regions)
• Nipple is supplied by lateral cutaneous branch of T4

Question 8

Why is the number of lymph nodes removed restricted in the pectoral region?

Answer 8

Cannot remove too many lymph nodes otherwise oedema can build up in the arm.

Question 9

Which lymph node is usually removed in the case of metastatic breast cancer?

Answer 9

Sentinel lymph node - axillary node is only removed in special cases.

Question 10

Where does the lymph from the breast drain?

Answer 10

• Infraclavicular group
• Parasternal nodes
• Mediastinal nodes
• Opposite breast

Question 11

What colour is dense tissue on an ultrasound?

Answer 11

Black

Question 12

What colour is glandular tissue on an ultrasound?

Answer 12

White

Question 13

What colour is a tumour on an MRI normally?

Answer 13

White with everything else black.

Question 14

Why can identifying tumours be more difficult in younger women?

Answer 14

Younger women often have denser breasts so can appear radiopaque on a mammogram, making it difficult to identify tumours.

Question 15

What are the signs of breast cancer?

Answer 15

• Speculation (tethers and draws in tissue)

- Calcification of milk ducts (easier to see in fatty breasts)

Question 16

What is gynaecomastia?

Answer 16

Enlargement of the breasts in males often due to a hormone imbalance or hormone therapy whereby glandular tissue can often be seen.

Question 17

What are some congenital abnormalities of the breast?

Answer 17

• Accessory nipples or breast tissue
• Underdevelopment or absence of the breast
• Poland syndrome

Question 18

What is Poland syndrome?

Answer 18

Birth defect characterised by underdeveloped chest muscle (pectoralis major), short ribs, less fat and nipple abnormalities.

Question 19

What is the breast composed of?

Answer 19

• Circular body

- Axillary tail (tail of Spence)

Question 20

What is the breast superficial to?

Answer 20

• Pectoralis major muscle (base of the breast lies on pectoral fascia)
• Serratus anterior muscle

Question 21

What produces milk during lactation?

Answer 21

The alveoli, which are tiny hollow sacs that are lined with milk secreting cuboidal cells. Surrounding the alveoli there are myoepithelial cells which contract in response to oxytocin, causing the milk to pushed out into the ducts.

Question 22

What is breast size determined by?

Answer 22

Largely determined by the amount of fat present and not the number of lobules as this is nearly the same in all women.

Question 23

What separates the lobules?

Answer 23

Fat is interdispersed as well as suspensory ligaments, which are strong and help to maintain breast shape.

Question 24

How is the nipple/areola supplied with blood?

Answer 24

Via the internal thoracic artery.

Question 25

How is the breast innervated?

Answer 25

• Branches of intercostal nerves (T2-6)
• Supraclavicular nerves (upper and lateral regions of the breast)

Nipple - dominant supply from the lateral cutaneous branch of T4

Question 26

What are some caused of enlarged lymph nodes?

Answer 26

• Infection
• Cancer
• Tuberculosis
• Arthritis
• Drug reactions

Question 27

Where is the only place that there are no lymph nodes?

Answer 27

Brain

Question 28

Where is the largest collection of lymph nodes found?

Answer 28

At bifurcation of the trachea.

Question 29

Where are common sites for breast cancer metastasis?

Answer 29

• Bone
• Regional lymph nodes
• Brain
• Lungs
• Liver

Question 30

Describe the trends in breast cancer.

Answer 30

Incidence is increasing whilst mortality is falling - better treatment and screening programs.

Question 31

What are the limitations of a mammogram?

Answer 31

• Ionising radiation (X-rays)
• False negative rate of at least 10%
• High false positive (only 15% with lumps will haveve malignant disease - leading to over treatment)

Question 32

What is the standard diagnostic test for breast cancer?

Answer 32

Mammogram - if a mammogram detects a suspicious site then an ultrasound is used.

Question 33

What is normal screening for breast cancer?

Answer 33

Every 2-3 years between the ages of 50 and 70. More frequent mammograms lead to a small but significant increase in breast cancer induced by radiation.