A woman’s breasts are rarely balanced (symmetrical). Usually, one breast is slightly larger or smaller, higher or lower, or shaped differently than the other.
The size and characteristics of the nipple also vary greater from one woman to another. In some women, the nipples are constantly erect. In others, they will only become erect when stimulated by cold or touch. Some women also have inverted (turned in) nipples. Inverted nipples are not a cause for concern unless the condition is a new change. Since there are hair follicles around the nipple, hair on the breast is not uncommon.
The nipple can be flat, round, or cylindrical in shape. The color of the nipple is determined by the thinness and pigmentation of its skin. The nipple and areola (pigmented region surrounding the nipple) contain specialized muscle fibers that respond to stimulation to make the nipple erect. The areola also houses the Montgomery’s gland that may appear as tiny, raised bumps on the surface of the areola. The Montgomery’s gland helps lubricate the areola. When the nipple is stimulated, the muscle fibers will contract, the areola will pucker, and the nipples become hard.
Breasts change through a woman’s life. Young women have more glandular tissue than older women, making their breasts former and denser. As women grow older, the proportion of fat increases and breasts tend to droop more.
On mammogram films, breast masses, including both non-cancerous and cancerous lesions, appear as white regions. Fat appears as black regions on the films. All other components of the breast (glands, connective tissue, tumors, calcium deposits, etc.) appear as shades of white on a mammogram. In general, younger women have denser breasts. As a woman ages, her breasts become less dense and the space is filled with fatty tissue shown as dark areas on mammography x-rays. It is usually easier for radiologists to detect breast cancer in older women because abnormal areas are easier to spot.
During each menstrual cycle, breast tissue tends to swell from changes in the body’s levels of oestrogen and progesterone. The milk glands and ducts enlarge, and in turn, the breasts retain water.
During menstruation, breasts may temporarily feel swollen, painful, tender, or lumpy. Doctors recommend that women practice monthly breast self-examinations the week following menstruation when the breasts are least tender.
Factors that may influence a woman’s breast size include:
- Volume of breast tissue
- Family history
- Weight loss or gain
- History of pregnancies and lactation
- Thickness and elasticity of the breast skin
- Degree of hormonal influences on the breast (particularly oestrogen and progesterone)