Anatomy of the breast

Question 1

what are breasts?

Answer 1

It is a modified apocrine sweat gland

Question 2

what is the breast made of?

Answer 2

It is made of:

• fat
• glandular tissue
• fibrous tissue

Question 3

What marks the base of the breast?

Answer 3

Rib 2 - Rib 6 (midclavicular line)

Question 4

where does the breast parenchyma extend?

Answer 4

Extends in the anterior axillary fold as the axillary tail of spence.

Question 5

What muscles underlie the breast?

Answer 5

Pectoralis Major

Laterally: Serratus Anterior + External Oblique

Question 6

What subunits are the breast made of? How many of them are there?

Answer 6

Ductal Lobular Units - 15-20 of them, each draining into a main duct

Question 7

How many milk ducts are there in the breast?

Answer 7

4-18

Question 8

What is interspersed between the ductal lobular units?

Answer 8

FAT

Question 9

What structures divide the breast?

Answer 9

Fibrous septae - Suspensory ligaments of Cooper

Question 10

what supplies blood to the breasts?

Answer 10

Branches of the lateral thoracic artery, internal thoracic artery, thoracoacromial artery, thoracodorsal artery and intercostal arteries.

Question 11

what supplies the breast skin?

Answer 11

The skin is supplied by the subdermal plexus which communicates with the deep parenchymal vessels.

Question 12

what supplies the nipple-areola?

Answer 12

The nipple-areola receives a branch from the internal thoracic artery in most cases.

Question 13

Is the upper part of a cranio-caudal mammogram the lateral or medial side?

Answer 13

Lateral

Question 14

What can breast cancer cause that appears as white streaks following the ducts?

Answer 14

Microcalcification

Question 15

What happens if the tumour interferes with the suspensory ligaments of Cooper?

Answer 15

Tethering of the skin

Question 16

Describe the blood supply to the breast.

Answer 16

Rich blood supply with branches from: 
Internal thoracic artery 
Lateral thoracic artery 
Thoraco-dorsal artery 
Thoraco-acromial artery 
Intercostal arteries

Question 17

What nerves are mainly involved in providing sensory innervation to the breast?

Answer 17

Anteromedial and anterolateral branches of intercostal nerves T3-T5

Question 18

What nerve supplies the nipple?

Answer 18

Lateral cutaneous branch of the intercostal nerve T4

Question 19

How are benign lumps different to breast cancer?

Answer 19

They are smooth and longer than they are tall in the longitudinal plane

Question 20

Where does the lymph from the superficial and deep parts of the breast initially drain to?

Answer 20

Superficial - subareolar plexus

Deep - submammary plexus

Question 21

Where does it then drain to from here?

Answer 21

Axillary group of pectoral lymph nodes

Question 22

When using dye to identify the sentinal lymph node, two blobs can appear on the X ray. What is the large blob usually caused by?

Answer 22

Bigger blob is probably the site of injection of the dye

Question 23

When using dye to identify the sentinal lymph node, two blobs can appear on the X ray. What is the large blob usually caused by?

Answer 23

Bigger blob is probably the site of injection of the dye

Question 24

describe the 3 ways of the venous drainage breast?

Answer 24

3 principle groups of veins

1. Perforating branches of the internal mammary vein
2. Tributaries of the axillary vein
3. Perforating branches of the posterior intercostal veins

Question 25

where is the innervation of the nipple? | how is the breast innervated

Answer 25

Dominant supply from the lateral cutaneous banch of T4. | Principally through the lateral and anterior cutaneous branches of the 2nd through 6th intercostal nerves

Question 26

what are the arrangments of the lymph nodes on the breast?

Answer 26

T1, T2, and T3.

Question 27

``` what is the lymphatic drainage breast and the axilla. Medially Laterally Anteriorly Posteriorly ```

Answer 27

- Medially: Serratus Anterior over 1st 4 ribs Laterally: Intertubercular groove of humerus & Biceps tendon, & Coracobrachialis Anteriorly: Pectoralis Major & Minor - Posteriorly: Teres Major, Subscapularis + tendon Latissimus Dorsi

Question 28

what is lymphoedema and what causes this and what does this cause?

Answer 28

- Removal of lymph nodes through surgeries - 2-3 years after patients get lymphoedema - Abnormal, generalized or regional accumulation of protein rich interstitial fluid - Oedema formation and change in tissue architecture - causes fat accumulation and scarring

Question 29

What is axillary reverse mapping?

Answer 29

- way to prevent lymphodema of the hands - Aims to identify and preserve nodes and/or lymphatics draining from the arm during ALND, thereby minimizing arm lymphedema Reverse mapping – blue dye, radioisotope or ICG

Question 30

congential abnormalities of the breast

Answer 30

Underdevelopment or absence of one breast (may coexist with muscle/ribcage anomaly) – *Poland syndrome Accessory nipples (polythelia) absent nipples (athelia) Accessory breast tissue Tubular breast defomity