Breast anatomy

What area does the base of the breast cover?

• Extends from lateral border of sternum to midaxillary line

• From 2nd to 6th ribs• Small part may extend towards the axilla – the

axillary tail

What two muscles does the breast overly?

• Pectoralis major• Serratus anterior

What separates the breast from the underlying muscle?

• Retromammary space• A potential space filled with loose connective

tissue

How is the breast attached to the skin that overlies it?

• Suspensory ligaments of Cooper• Helps support the lobules of the breast

On what line does the nipple lie?

• Mammary ridge/milk line• From the anterior axillary fold to the groin• Supernumerary nipples can be occur along

this line• Also axillary breasts

How is the breast divided for descriptive purposes?

• Quadrants

What glands are found on the areola?

• Sebaceous (Montgomery) glands

• Secrete oily substance following pregnancy

• Oily substance protects the nipple from irritation

How many lobules are in the breast? How are they separated?

• 15-20 lobules of glandular tissue• Separated by suspensory ligaments of Cooper

Describe the drainage of milk from a lobule?

• Each lobule drains into a lactiferous duct• Each lactiferous duct opens on the nipple

What arteries supply the breast?

• Medial mammary – From internal thoracic (mammary)/anterior intercostal

• Lateral mammary – From lateral thoracic artery & posterior intercostals

What is the nerve supply to the breast?

• T4-6 intercostal nerves

What different areas do the lymphatics of the breast drain to?

Auxiliary nodes

Parasternal nodes

Contralateral parasternal nodes

Contralateral breastSubdiaphragmatic/hepatic nodes

Inguinal lymph nodes (rare)

Interpectoral (rotter’s) nodes

What changes does the breast go through during pregnancy? (6)

• Lengthening and branching of ducts• Development of secretory alveoli• Vascularity increases• Nipples enlarge• Areola becomes more prominent• Lobular structure more prominent

What effect do progesterone and oestrogen have on breast tissue?

• Progesterone – lobular development (growth)• Oestrogen – ductal growth• Combined – suppress lactation

Benefits of breast feeding• Bonding• Infection• Cheap• Convenient• Sterile

Who should not breast feed

• Alcohol misuse• Certain drugs-methotrexate, cyclosporine,

lithium• Active TB• HIV• Breast Cancer Rx• Infant with galactosemia

Difficulties with Breast feeding• 2/3 of women have some problem• Cracked nipple• Mastitis• S. Aureus• Preemie• Need advice and support