Breast anatomy

Question 1

What factors affect the breasts?

Answer 1

Menstrual cycle/ hormones 
Age and sexual maturity 
Inherited factors
Pregnancy 
Lactation 
Nutrition

Question 2

How do the breasts develop in utero?

Answer 2

Along the mammary ridge (milk line) which runs from the groin to the axilla
[Regresses in normal development leaving breast to develop in select region]

Question 3

What is the surface anatomy of the breast base?

Answer 3

Ribs 2-6 (sternal angle used to identify rib 2)
Lateral sternal border to midaxillary line
Extends superolaterally into the axilla (important to examine during breast examination)

Question 4

What is the areolar?

Answer 4

Region of pigmented skin around the nipple, often darkens during and after pregnancy
Sweat and sebaceous (Montgomery) glands open into the areolar

Question 5

What is the nerve innervation to the breasts?

Answer 5

T4-T6 intercostal nerves

Question 6

What is mastalgia?

Answer 6

Pain in the breast

Question 7

What is the arterial supply to the breast?

Answer 7

Lateral mammary branches (from lateral thoracic and posterior intercostal arteries)
Medial mammary branches (from internal thoracic and anterior intercostal arteries)

Question 8

What type of gland is the breast?

Answer 8

Modified apocrine sweat gland (composed of fat, fibrous and glandular tissues)

Question 9

What muscles do the breasts sit anteriorly to?

Answer 9

Pectoralis major (and minor)
Serratus Anterior

Question 10

What causes sex differences in breasts?

Answer 10

Secondary breast development during female puberty

Question 11

What can happen if the mammary ridge fails to regress typically?

Answer 11

Supranumerary nipples (polythelia) 
Accessory breasts (polymastia)

Question 12

What drains into the nipple?

Answer 12

Lacteriferous ducts (approx. 15-20)

Question 13

What is the retromammary space and its function?

Answer 13

Space filled with loose conncetive tissue and fat between the breast tissue and pectoralis fascia
Function is to permit free movement of breast independent of pectoralis major

Question 14

What ligaments support the breast?

Answer 14

Suspensory (Cooper) ligaments - run through breast and attach to the dermis

Question 15

What is Paget’s Disease of the breast/ nipple?

Answer 15

Cancer of the breast which spreads along duct to involve nipple

Question 16

How do the breasts change with age?

Answer 16

Increased adipose tissue (compared to fibrous, connective tissue)

Question 17

What can cause breast pain?

Answer 17

Cyclical
Non-cyclical (pain present at all time)
Non-breast origin (e.g. MSK, skin, respiratory, cardiac)

Question 18

What is the main lymph drainage from the breast tissue, nipple and aleolar?

Answer 18

Para-sternal (inter thoracic) nodes

Anterior and central axillary nodes (esp. medial aspect of breast)

Question 19

What is the lymph drainage from the breast skin?

Answer 19

Axillary, infraclavicular and deep cervical nodes

Question 20

What is axillary node sampling or clearance, and what can it result in?

Answer 20

Sampling = removal of some nodes
Clearing = removal of all nodes

Can result in lymphedema (due to limited ability to drain through axillary region)

Question 21

What symptoms can indicate a breast pathology?

Answer 21

Pain
Lump
Nipple discharge or inversion
Skin changes

Question 22

What observable changes of the breast indicate breast cancer?

Answer 22

Asymmetric or new onset nipple retraction
P’eau d’orange (orange peel texture of skin caused by local oedema)
Dimpling of the skin (can be caused by pulling of suspensory ligaments that are attached to the dermis)
Nipple discharge or bleeding
Paget’s Disease of the breast or nipple
Inflammatory changes

Question 23

What is gynaecomastia?

Answer 23

Enlargement of male breasts caused by proliferation of the glandular component