Lecture 7 - Lymphatic drainage of the breast Flashcards Preview

Y1 - Anatomy of the Thorax > Lecture 7 - Lymphatic drainage of the breast > Flashcards

Flashcards in Lecture 7 - Lymphatic drainage of the breast Deck (33)
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1
Q

What level does the breast extend over?

A

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

2
Q

What muscle does the breast overlie?

A

Pectoralis major.

3
Q

What is the breast made up of?

A

Glandular tissue, fat and fibrous tissue.

4
Q

How does the tissue distribution change in pregnant women?

A

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

5
Q

What is the structure of the breast?

A
  • 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
6
Q

Describe the blood supply to the breast.

A

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
7
Q

Describe the nerve supply to the breast.

A
  • 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
8
Q

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

A

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

9
Q

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

A

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

10
Q

Where does the lymph from the breast drain?

A
  • Infraclavicular group
  • Parasternal nodes
  • Mediastinal nodes
  • Opposite breast
11
Q

What colour is dense tissue on an ultrasound?

A

Black

12
Q

What colour is glandular tissue on an ultrasound?

A

White

13
Q

What colour is a tumour on an MRI normally?

A

White with everything else black.

14
Q

Why can identifying tumours be more difficult in younger women?

A

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

15
Q

What are the signs of breast cancer?

A
  • Speculation (tethers and draws in tissue)

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

16
Q

What is gynaecomastia?

A

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

17
Q

What are some congenital abnormalities of the breast?

A
  • Accessory nipples or breast tissue
  • Underdevelopment or absence of the breast
  • Poland syndrome
18
Q

What is Poland syndrome?

A

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

19
Q

What is the breast composed of?

A
  • Circular body

- Axillary tail (tail of Spence)

20
Q

What is the breast superficial to?

A
  • Pectoralis major muscle (base of the breast lies on pectoral fascia)
  • Serratus anterior muscle
21
Q

What produces milk during lactation?

A

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.

22
Q

What is breast size determined by?

A

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

23
Q

What separates the lobules?

A

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

24
Q

How is the nipple/areola supplied with blood?

A

Via the internal thoracic artery.

25
Q

How is the breast innervated?

A
  • 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

26
Q

What are some caused of enlarged lymph nodes?

A
  • Infection
  • Cancer
  • Tuberculosis
  • Arthritis
  • Drug reactions
27
Q

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

A

Brain

28
Q

Where is the largest collection of lymph nodes found?

A

At bifurcation of the trachea.

29
Q

Where are common sites for breast cancer metastasis?

A
  • Bone
  • Regional lymph nodes
  • Brain
  • Lungs
  • Liver
30
Q

Describe the trends in breast cancer.

A

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

31
Q

What are the limitations of a mammogram?

A
  • 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)
32
Q

What is the standard diagnostic test for breast cancer?

A

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

33
Q

What is normal screening for breast cancer?

A

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.