Breast: Normal Anatomy

Question 1

What is the breast?

Answer 1

• Secondary sexual feature of females
• Rudimentary structure in males
• Source of nutrition for neonates

Question 2

What is the association between the breast and malignancy?

Answer 2

Site of malignant change in as many as 1 in 10 women

Question 3

What does breast size and shape depend on?

Answer 3

Genetic, racial and dietary factors

Question 4

What are the general features of the breast?

Answer 4

• Modified and highly specialized sweat glands
• No special capsule or sheath
• Well developed in females

Question 5

What is the surface markings of the breast?

Answer 5

• Extends from 2nd/3rd rib to 6th rib

- Extends from sternal edge to midaxillary lie

Question 6

What is the axillary tail (of spence)/process?

Answer 6

A small part of the breast which may extends towards the axillary fossa

Question 7

What is the function of the retomammary space (bursa)?

Answer 7

Helps some degree of movement

Question 8

What does the breast lie on?

Answer 8

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

Question 9

How does the breast attach to the dermis?

Answer 9

By the suspensory ligament of cooper which helps support the lobules of the gland

Question 10

What is the nipple?

Answer 10

Prominence of the breast

Question 11

What is the areola?

Answer 11

Pigmented area around the nipple

Question 12

What is the basic structure of the breast?

Answer 12

• Each breast contains 15-20 lobules of glandular tissue (parenchyma)
• Each lobule is drained by a lactiferous duct – opens independently on the nipple
• Each duct has a dilated portion – lactiferous sinus

Question 13

What are the features of the nipple?

Answer 13

• No fat or hair
• Contains collagenous dense connective tissue, elastic fibres and bands of smooth muscle
• The tips of the nipples are fissured with lactiferous ducts opening into them
• Position : variable or 4th intercostal space

Question 14

What are the features of the areola?

Answer 14

• Skin covering the nipple and areola contains numerous sweat & sebaceous glands
• Enlarge during pregnancy
• Oily material secreted by the sebaceous gland provides a protective lubricant for nipple and areola

Question 15

How is the breast divided for description of pathology?

Answer 15

Into 4 quadrants

• Superomedial quadrant
• Inferomedial quadrant
• Superolateral quadrant (axillary tail is an extension)
• Inferolateral quadrant

Question 16

When does temporary enlargement of the male breast occur?

Answer 16

In the newborn and during puberty

Question 17

What are the features of the male breast?

Answer 17

• Rudimentary throughout life
• Formed by small ducts without lobules or alveoli
• Little supporting fibroadipose tissue

Question 18

How does the breast develop?

Answer 18

• Mammary crests or ridges appear during 4th week
• These crests extend from axillary region to inguinal region
• The crests usually disappear except in the pectoral region
• Primary mammary buds – Secondary buds – lactiferous ducts and their branches

Question 19

Athelia

Answer 19

Absence of nipple

Question 20

Polythelia

Answer 20

An extra nipple

Question 21

Polymastia

Answer 21

An extra breast

Question 22

Amastia

Answer 22

Absence of breast

Question 23

Gynecomastia

Answer 23

• Postnatal development of rudimentary lactiferous ducts in males
• During puberty around 2/3rd of boys develop varying degrees of hyperplasia of the breasts

Question 24

What is the blood supply to the breasts?

Answer 24

Supplied by Branches of 
axillary artery, internal thoracic, and
some intercostal arteries
-Thoraco acromial artery
-Lateral thoracic artery
-Internal mammary (thoracic) artery

Question 25

What is the nerve supply to the breasts?

Answer 25

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

Question 26

Why is the lymphatic drainage of the breast of great clinical significance?

Answer 26

Metastatic dissemination occurs primarily by the lymphatic routes

Question 27

What is the lymphatic drainage of the beast?

Answer 27

- Most lymph (more than 75%) from lateral quadrants – axillary lymph nodes - Some lymph may drain directly to supraclavicular or inferior cervical nodes - Lymph from medial quadrants – parasternal or to opposite breast

Question 28

What is the sentinel node?

Answer 28

First draining node

Question 29

How is the sentinel localised?

Answer 29

- A radiolabelled colloid is used to locate the sentinel node - At the time of surgery, a vital blue dye is injected - Combination of radioisotope and dye provides most accurate means of localizing the node

Question 30

What is identification of the sentinel node used for?

Answer 30

Lymphatic mapping and staging of patients

Question 31

What is the soft tissue of the breast made from?

Answer 31

Made up of lobes which contains a network of glandular tissue consisting of branching ducts and secretory lobules in a connective tissue stroma.

Question 32

What is the terminal duct lobular unit?

Answer 32

Functional milk secretory component of the breast

Question 33

Describe the connective tissue stroma which surrounds the lobules in the breast.

Answer 33

It is dense and fibrocollagenous

Question 34

Describe the interlobular tissue of the breast?

Answer 34

Loose texture

Question 35

What can be seen on histology of the breast?

Answer 35

- Extensive branching duct system - Surrounded by dense fibrous interlobular tissue and adipose tissue - Ducts and acini are lined by 2 layers of cells: luminal epithelial cells and myoepithelial cells

Question 36

What age related changes occur in the breast prepuberty?

Answer 36

- Neonatal breast contain lactiferous ducts but no alveoli - Until puberty, little branching of the ducts occurs - Slight breast enlargement reflects the growth of fibrous stroma and fat

Question 37

What age related changes occur in the breast during puberty?

Answer 37

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

Question 38

What age related changes occur in the breast post-menopausal?

Answer 38

- Progressive atrophy of lobules and ducts | - Fatty replacement of glandular tissue

Question 39

What is colostrum?

Answer 39

Protein rich fluid, available for a few days after birth. It is rich in maternal antibodies

Question 40

What can be seen on histology of a lactating breast?

Answer 40

- Acini distended with milk - Thin septa between the lobules - At higher magnification acini with eosinophilic material containing clear vacuoles can be seen?

Question 41

What stimulates milk production?

Answer 41

- Suckling, neurohormonal reflex | - Prolactin and oxytocin

Question 42

What diagnostic methods are used in diagnosing breast pathology?

Answer 42

- Imaging including mammography and ultrasound - Fine needle aspiration cytology - Core biopsy

Question 43

How common is breast cancer?

Answer 43

- 20% of all cancers in women - Commonest cause of death in women in 35-55 age group - In UK, any woman has a 1in 9 chance of developing breast cancer

Question 44

What are some signs of breast cancer?

Answer 44

- Skin dimpling - Oedema of skin - Abnormal contours - Nipple retraction and deviation

Question 45

Give examples of benign breast tumours.

Answer 45

- Fibroadenomas - Duct papillomas - Adenomas - Connective tissue tumours

Question 46

What are the features of Paget's disease?

Answer 46

- Erosion of the nipple resembling eczema | - Associated with ductal or invasive carcinoma