Breast anatomy

Mature female breasts are made up of:

• Fatty tissue
• Fibrous connective tissue and ligaments which provide support for the breast.
• 15 – 20 lobes which, like bunches of grapes, are divided into smaller lobules. These are the milk-producing glands.
• Ducts which transport the milk to the nipple.

The darker skin surrounding the nipple is called the areola. Sweat glands contained in the areola moisturise the skin to assist with breastfeeding. The tiny bumps on the areola are known as Montgomerey’s tubercles.

Prior to menopause (when periods have stopped as the ovaries cease producing oestrogen) breasts have more glandular tissue than fatty tissue. This means that the breast tissue is dense. It is more difficult to read a mammogram when the breast tissue is very dense, making mammograms less reliable in young women.

After menopause, the amount of glandular tissue decreases and the remaining tissue shrinks, so that there is a greater proportion of fatty tissue, resulting in lower breast density.

Breast density remains high in women taking hormone replacement therapy (HRT), so mammograms may also be less accurate in these women.

The breast sits on the chest (pectoral) muscles which cover the ribs.

The female breast extends from just below the collarbone (clavicle) to the armpit and across to the breastbone (sternum) in the centre of the chest. Both men and women have breasts, but women have significantly more breast (glandular) tissue than men.

In childhood, boys and girls have similar breast tissue. During puberty, testosterone levels rise in boys, and oestrogen levels stay low, which prevents further breast development.

During puberty, girls will often feel a firm, tender “breast bud” behind their nipples. This is the glandular tissue beginning to develop under the influence of hormones produced by the ovaries and pituitary gland.