Breasts

Breasts in humans are the organs designed to provide milk to the growing babies.

• The breasts of an adult woman are milk-producing, tear-shaped glands.
• A layer of fatty tissue surrounds the breast glands and extends throughout the breast, which gives the breast a soft consistency and gentle, flowing contour.
• The breast is responsive to a complex interplay of hormones that cause the breast tissue to develop, enlarge and produce milk.
• Each breast contains 15 to 20 lobes arranged in a circular fashion.
• Each lobe is comprised of many lobules, at the end of which are tiny bulblike glands, or sacs, where milk is produced in response to hormonal signals.
• Ducts connect the lobes, lobules, and glands; in nursing mothers, these ducts deliver milk to openings in the nipple.
• Breast tissue is drained by lymphatic vessels that lead to axillary nodes (which lie in the axilla) and internal mammary nodes (which lie along each side of the sternum).

Anatomy of human breasts

The breasts of an adult woman are milk-producing, tear-shaped glands. They are supported by and attached to the front of the chest wall on either side of the breast bone or sternum by ligaments. They rest on the major chest muscle, the pectoralis major. The breast has no muscle tissue. A layer of fat surrounds the glands and extends throughout the breast.

Hormones and breasts

The breast is responsive to a complex interplay of hormones that cause the tissue to develop, enlarge and produce milk. The three major hormones affecting the breast are estrogen, progesterone and prolactin, which cause glandular tissue in the breast and the uterus to change during the menstrual cycle.

Lobes of breasts

Each breast contains 15 to 20 lobes arranged in a circular fashion. The fat (subcutaneous adipose tissue) that covers the lobes gives the breast its size and shape. Each lobe is comprised of many lobules, at the end of which are tiny bulb like glands, or sacs, where milk is produced in response to hormonal signals.

Ducts of breasts

Ducts connect the lobes, lobules, and glands in nursing mothers. These ducts deliver milk to openings in the nipple. The areola is the darker-pigmented area around the nipple.

Breast diseases

Most women experience breast changes at some time. Your age, hormone levels, and medicines you take may cause lumps, bumps, and discharges (fluids that are not breast milk).

Symptoms of breast diseases

If you have a breast lump, pain, discharge or skin irritation, see your health care provider. Minor and serious breast problems have similar symptoms. Although many women fear cancer, most breast problems are not cancer.

Common breast changes

Some common breast changes are

• Fibrocystic breast changes - lumpiness, thickening and swelling, often just before a woman's period
• Cysts - fluid-filled lumps
• Fibroadenomas - solid, round, rubbery lumps that move easily when pushed, occurring most in younger women
• Intraductal papillomas - growths similar to warts near the nipple
• Blocked milk ducts
• Milk production when a woman is not breastfeeding.

Lymph nodes draining the breasts

Blood and lymph vessels form a network throughout each breast. Breast tissue is drained by lymphatic vessels that lead to axillary nodes (which lie in the axilla) and internal mammary nodes (which lie along each side of the breast bone). When breast cancer spreads, it is frequently to these nodes.

• Axillary lymphatic plexus
• Cubital lymph nodes
• Superficial axillary (low axillary)
• Deep axillary lymph nodes
• Brachial axillary lymph nodes
• nterpectoral axillary lymph nodes (Rotter nodes)
• Paramammary or intramammary lymph nodes
• Parasternal lymph nodes (internal mammary nodes)

Breasts Resources
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