The breast contains lobules composed of alveoli (milk sacs) that produce milk and ducts that take the milk to the nipple. These are surrounded by fatty tissue and connective tissue.

Normal structures which may be felt as changes in your breast include:

• Normal breast tissue – accentuated by changes in hormones
• Prominent fat lobule – a soft nodule of fat tissue
• Prominent rib
• Normal lymph node within or near the main breast tissue
• Scar tissue
• Skin lesions – e.g. sebaceous cyst, epidermal inclusion cyst
• Accessory breast tissue – a focal area of extra breast tissue, often found in the armpit
• Montgomery’s tubercle – a modified sebaceous gland found on the areola, which is the darker skin immediately surrounding the nipple.

1. Rib
2. Chest wall muscle
3. Fat & Connective tissue
4. Lobule
5. Ducts
6. Nipple
7. Skin

Adapted from Hughes LE, Mansel RE and Webster DJT, Benign Disorders and Diseases of the Breast, Concepts and Clinical Management, 2nd Edition, London: WB Saunders, 2000. p 36