Normal Anatomy of the Breasts

Question 1

Describe the development of the breasts - embryology

Answer 1

Mammary crests or ridges appear during 4th week
Crests extend from axillary region to inguinal region
Crests disappear except in the pectoral region
Primary - secondary mammary buds - lactiferous ducts and their branches

Question 2

What are some general features of the breast?

Answer 2

Modified and highly specialised swear glands
No special capsule or sheath
Well developed in females
Size and shape differs from genetics, racial and dietary factors

Question 3

What is location of the breast?

Answer 3

Vertical - 2nd or 3rd rib to 6th rib
Transverse - sternal edge to midaxillary line
Lies on deep pectoral fascia

Question 4

What is the axillary tail or process?

Answer 4

Small part of breast may extend towards the axillary fossa

Question 5

What does the retromammary space (bursa) help?

Answer 5

Helps some degree of movement

Question 6

What are the relations of the breast?

Answer 6

2/3rd of the breast rests on pectoral fascia covering pectoralis major
1/3rd rests on fascia covering serratus anterior

Question 7

How is the breasts attached to the dermis?

Answer 7

By suspensory ligament of cooper - helps supports the lobules of the gland

Question 8

How many lobules does the breast contain?

Answer 8

15-20 lobules of glandular tissue - parenchyma

Question 9

What drains each lobule of the breast?

Answer 9

Lactiferous duct - open independently on the nipple
Each duct has a dilated portion called lactiferous sinus

Question 10

What are some features of the nipple?

Answer 10

No fat or hair
Contains collagenous dense connective tissue, elastic fibres and bands of smooth muscle
Tips of nipples are fissured with lactiferous ducts

Question 11

What is the position of the nipple?

Answer 11

Variable or 4th intercostal space

Question 12

What are some features of the areola?

Answer 12

Skin covering the nipple and areola contains numerous sweat and sebaceous glands
Enlarges in pregnancy
Oily material secreted by sebaceous gland - protective lubricant

Question 13

Describe the male breast

Answer 13

Formed by small ducts without lobules or alveoli
Little supporting fibro adipose tissue
Temporary enlargement in new born and during puberty

Question 14

What is polymastia and polythelia?

Answer 14

Polymastia - an extra breast
Polythelia - an extra nipple

Question 15

What is athelia or amastia?

Answer 15

Absence of nipple or breast

Question 16

What is the blood supply of the breasts?

Answer 16

Branches of axillary artery, internal thoracic and some intercostal arteries
Thoraco-acromial artery
Local thoracic artery
Internal mammary artery

Question 17

Describe the nerves of the breasts

Answer 17

Anterior and lateral cutaneous branches of 4 - 6th intercostal nerves
They cover sensory fibres of the skin and carry sympathetic fibres to blood vessels and smooth muscle around the nipple

Question 18

Describe the lymphatic drainage of the breasts

Answer 18

Most lymph from lateral quadrants to axillary lymph nodes
Some lymph may drain directly to supraclavicular or inferior cervical nodes
Medial quadrants - parasternal or opposite breast

Question 19

What is the role of sentinel lymph node biopsy?

Answer 19

Lymphatic mapping and staging
Radiolabelled colloid is used to locate it
During surgery, vital blue dye is injected
Dye and radioisotope is most accurate for localising node

Question 20

What is the role of the terminal duct lobular unit?

Answer 20

Functional milk secretory component of the breast

Question 21

Describe the connective tissue stroma which surrounds the lobules

Answer 21

Dense and fibro-collagenous, whereas intralobular tissue has a loose texture

Question 22

Describe normal breast on histology

Answer 22

Ducts and acini are lined by 2 layers of cells - luminal epithelial cells and myoepithelial cells
Extensive branching duct system

Question 23

What are the prepuberty related changes which happen to the breasts?

Answer 23

Neonatal breasts contain lactiferous ducts but no alveoli
Until puberty when little branching ducts appear
Slight breast enlargement reflects growth of fibrous stroma and fat

Question 24

What are the puberty changes which happen to the breasts?

Answer 24

Branching of lactiferous ducts
Solid, spheroidal masses of granular polyhedral cells
Accumulation of lipids in the adipocytes

Question 25

What are the post-menopausal changes that happen to the breasts?

Answer 25

Progressive atrophy of the lobules and ducts
Fatty replacement of glandular tissue

Question 26

What is the difference of breast tissue on histology when pregnant?

Answer 26

Enlarged lobules
Acini are dilated
Epithelium varies from cuboidal to low columnar

Question 27

What does the lactating breast look like on histology?

Answer 27

Acini distended with milk
Thin septa between the lobules
Acini with eosinophilic material containing clear vacuoles

Question 28

What are the diagnostic methods used for breast cancer?

Answer 28

Mammography and US
Fine needle aspiration cytology
Core biopsy

Question 29

What are types of benign breast tumours?

Answer 29

Fibroadenomas, duct papilloma, adenomas and connective tissue tumours

Question 30

What is paget’s disease of the nipple?

Answer 30

Erosion of the nipple resembling eczema and associated with ductal or invasive carcinoma