Breast

Female human breasts

A woman breast-feeding her child; image painted by Mary Cassatt, 1890

Anatomy, function, and clinical significance of the human breast

The breast is a glandular organ located on the anterior chest wall of humans and other mammals. In humans, breasts develop as secondary sexual characteristics, particularly in females, where they serve a primary function in lactation. The structure of the breast includes mammary glands, connective tissue, adipose tissue, and a network of ducts.

Breasts undergo developmental, hormonal, and age-related changes, influenced by factors such as puberty, pregnancy, and menopause. In addition to their reproductive role, breasts have cultural, social, and medical significance.

Anatomy of the Breast

The breast is composed of various tissues that contribute to its function and appearance.

Macroscopic Structure

Each breast consists of:

• Mammary glands: Functional units responsible for milk production.
• Lobules: Small clusters of milk-producing glands.
• Lactiferous ducts: Tubes that transport milk from lobules to the nipple.
• Adipose tissue: Fat tissue that determines the size and shape of the breast.
• Cooper's ligaments: Fibrous bands providing structural support.
• Nipple and Areola: The nipple contains openings of the lactiferous ducts, while the areola is the pigmented area surrounding the nipple.

Vascular and Lymphatic Supply

Breasts receive blood supply from:

• Internal thoracic artery
• Lateral thoracic artery
• Intercostal artery

The lymphatic system of the breast plays a crucial role in immune defense and cancer metastasis. The primary lymphatic drainage is to the axillary lymph nodes, followed by the supraclavicular and parasternal nodes.

Innervation

Breast sensation is supplied by:

• Intercostal nerves (T3-T5): Provide sensory input to the nipple and surrounding tissue.
• Supraclavicular nerves: Supply sensation to the upper portion of the breast.

Development and Hormonal Influence

Breast development occurs in distinct phases:

Embryological Development

Breast tissue originates from the mammary ridge (milk line) during fetal development. By birth, rudimentary mammary glands are present in both males and females.

Pubertal Changes

During puberty, estrogen and progesterone stimulate the growth of ductal and glandular tissue, leading to breast enlargement in females.

Pregnancy and Lactation

During pregnancy:

• Increased levels of estrogen, progesterone, and prolactin promote breast enlargement and ductal expansion.
• After childbirth, prolactin stimulates milk production, while oxytocin triggers milk ejection.

Menopause and Aging

Postmenopausal changes involve:

• Reduction in estrogen levels, leading to glandular tissue shrinkage.
• Increase in adipose tissue, which alters breast size and shape.

Clinical Significance

Breast health is a crucial aspect of women's health and oncology, as various conditions can affect breast tissue.

Common Breast Conditions

• Mastitis: Infection of the breast, often occurring during breastfeeding.
• Fibroadenoma: A benign breast tumor common in young women.
• Breast cysts: Fluid-filled sacs in the breast.
• Gynecomastia: Enlargement of breast tissue in males due to hormonal imbalances.

Breast Cancer

• Breast cancer is the most common malignancy in women worldwide.
• It originates from the ductal or lobular epithelium and may spread to lymph nodes.
• Risk factors include genetic predisposition (BRCA1/BRCA2 mutations), hormonal exposure, and lifestyle factors.
• Screening and Diagnosis:
• Mammography: Standard imaging for early breast cancer detection.
• Breast ultrasound and MRI: Used in high-risk cases.
• Biopsy: Confirms malignancy through histopathological examination.

Breast Reconstruction and Augmentation

• Breast augmentation involves the use of implants or fat grafting for cosmetic or reconstructive purposes.
• Breast reduction surgery is performed to alleviate symptoms related to macromastia (large breasts).

Breastfeeding and Maternal Health

Breastfeeding offers benefits such as:

• Optimal nutrition for infants, providing antibodies and essential nutrients.
• Lower risk of breast and ovarian cancer in mothers.
• Promotion of bonding between mother and child.

Male breast

Men also have breasts. They are built the same way as those of women but are much smaller and underdeveloped. Men cannot use their breast for breastfeeding. Their breasts will usually not produce milk, but might become larger and produce milk during some diseases or with some hormonal medical treatments.

Cultural and Social Perspectives

Breasts have symbolic, aesthetic, and sociocultural significance across different cultures. In many societies, breasts are associated with fertility, femininity, and beauty standards.

• Breast representation in art and media: Breasts have been depicted in sculptures, paintings, and modern media.
• Cultural attitudes toward breastfeeding: Public breastfeeding is widely accepted in some cultures but remains a topic of debate in others.
• Breast self-image and body confidence: Societal expectations influence self-perception and body image issues.

See Also

• Mammary gland
• Lactation
• Breast cancer
• Gynecomastia
• Mammoplasty
• Mastectomy
• Areola