Breast

Question 1

What is the difference between the nipple and areola?

Answer 1

NIpple:

• ciruclarly arranged smooth muscle
• contains opening of 15-20 lactiferous ducts

Areola:

• circular pigmented skin surrounding nipple
• contains 18-20 sebaceous glands

Question 2

What is the location of the breast?

Answer 2

• over ribs 2-6

- from lateral border of sternum to mid axillary line

Question 3

What is the structure of the breast?

Answer 3

Nipple:

• anterior and central
• circularly arranged smooth muscle
• 15-20 lactiferous ducts

Areola:

• circular pigmented skin surrounding nipple
• 18-20 sebaceous glands

Lobes:

• breast divided into 15-20 lobes
• lobes contain lobules (mammary glands) where milk is produced

Mammary glands:

• modified sweat glands
• in lobes of breast
• supported by connective and adipose tissue

Suspensory ligaments:

• between mammary glands and dermis
• support breast structure

Retromammary space:
- between breast and deep pectoral fascia

Question 4

What is the process of milk production?

Answer 4

1. Alveoli inside mammary lobules secrete milk
2. 15-20 alveoli drain milk into lactiferous ducts
3. lactiferous ducts converge into a lactiferous sinus near the nipple and secrete milk

Question 5

Which nerves innervate the breast?

Answer 5

Branches of intercostal nerves 4-6 (anterior cutaneous and lateral cutaneous nerves)

Question 6

What is the vascular supply for the breast?

Answer 6

Arterial supply:

• anterior intercostal artery
• posterior intercostal arteries 2-4
• lateral thoracic arteries
• thoracoacromial arteries

Venous drainage:

• axillary vein
• internal thoracic vein

Question 7

What is the lymphatic drainage of the breast?

Answer 7

Subareolar Lymphatic Plexus:
- all breast lymph drains here originally

Pectoral & Axillary nodes:
- 75% of lymph (lateral aspect) draining from breast

Inferior Phrenic & Parasternal Nodes:
- 25% of lymph (medial aspect) draining from breast

Question 8

Which 5 hormones are involved in the production of milk?

Answer 8

FSH (follicle stimulating hormone)

LH (luteinising hormone)

Oestrogen & progesterone
Prolactin
Oxytocin

Question 9

What are the roles of hormones in milk production?

Answer 9

FSH & LH = gonadotrophin hormones

• stimulate production of oestrogen and progesterone
• produced in anterior pituitary gland

Oestrogen & progesterone:

• stimulate growth of bresat tissue
• maintain breast function
• produced in the ovaries

Prolactin:

• stimulates milk production
• produced in anterior pituitary gland

Oxytocin:

• stimulates milk ejection by causing smooth muscle in nipples to contract
• produced in posterior pituitary gland