The breasts (from the Latin sinus, “curvature, sinuosity, fold”) are present in men and in women but they are only functional in women. Their biological function is the production of milk for breastfeeding the baby.

The breasts are located at the level of the thorax, in front of the pectoral muscle on each side and extend in height to the collarbone and, in width from the armpit to approximately the middle of the sternum. They are asymmetrical and do not contain muscle. They are supported by ligaments.

The breasts are made up of a mammary gland, connective tissue, and fatty tissue. It is this fatty tissue that gives them shape and volume. Covered by the skin, they have at their center a pigmented region called the mammary areola which itself surrounds the nipple (the milk ejection port). The mammary gland is formed from 15 to 25 lobes which contain lobules. These lobules contain secretory units, the berries, which produce milk. The latter is transported from the lobules to the nipple by secretory ducts, the milk ducts.

Breast development

• Breasts at birth

The mammary gland is immature and remains at rest until puberty. In boys, it remains at this stage for life.

• The breasts at the puberty

In girls, the breasts will develop under the influence of hormones secreted by the ovary (estrogen and progesterone). We then see:

• An increase in breast volume,
• A protrusion of the nipple with an enlargement and pigmentation of the areola,
• Development of the ducts and glands that will produce milk.

The final development of the breasts will take place during the first pregnancy.

• Breasts during and after pregnancy

Under the action of several hormones (mainly estrogen, progesterone and prolactin), the breasts increase in size by the proliferation of ducts and lobules but also of fatty tissue. The nipple sticks out and the areola takes on a grainy appearance because it is traversed by glands which secrete sweat which will serve as lubricant during breastfeeding.

• Breasts at menopause

Hormonal secretion is stopped, the mammary gland atrophies. However, its volume does not always decrease because it is replaced by fibrous or adipose tissue.

The biological function of the breasts is the production and secretion of milk to nourish the baby: this is the phenomenon of lactation.

After childbirth, a hormone, prolactin, stimulates the lobules of the mammary gland which then produce milk. Milk is transported and ejected through the milk ducts which contract under the effect of another hormone, oxytocin. Lactation is maintained thanks to the baby’s sucking reflex: stimulation of the nipple causes the production of prolactin which again triggers the secretion of milk.

Benign pathologies

• Premenstrual mastodynia: corresponds to the painful tension of the breasts in the days preceding the rules. A trivial phenomenon, however, it may require treatment if the pain is too intense.
• Discharge from the nipple: these are abnormal outside of pregnancy and breastfeeding. The cause could be a benign tumor, a missed period, or a tumor in a milk duct. It is then necessary to consult a doctor.
• Fibro-adenomas: benign tumors generally hard and isolated. However, it is necessary to monitor them.
• Mastoses: these are benign tumors characterized by densification of the glandular tissue. Painful nodules (an abnormal, usually rounded lump) or cysts that are frequently filled with fluid may appear. These tumors are detectable on palpation. Oral intake of progestin (a derivative of progesterone) or puncture of cysts to evacuate the liquid are effective.

Breast cancer: the first female cancer, it is the main cause of death in women with nearly 11 deaths estimated in 900 in France. According to the National Cancer Institute (2015), around 4 new cases of breast cancer were expected in 54. One in nine women is affected and the risk increases with age.

Breast cancer can also develop in men. With only 1% of the total number of breast cancers and 0,5% of male cancers, cases are rare.

Stretch marks: tears in the deep dermis. Stretch marks are mainly found on the stomach, breasts, arms, buttocks and thighs. Very common, they can appear during pregnancy, during a significant and sudden loss of weight or during adolescence.

Prevention

According to the WHO (5), eating a healthy diet, exercising and fighting alcohol consumption, overweight and obesity could have an impact on the occurrence of breast cancer.

Breastfeeding, benefits for mother and child

An international study (6) published on January 29 and synthesizing data from 164 other studies, concludes that breastfeeding could prevent the death of 823 children under 000 years of age each year around the world and could prevent childhood illnesses. In addition, the authors attest that it would reduce the annual number of deaths from breast cancer by 5. These conclusions join those of the WHO (20) which, in 000, already spoke of 7 children saved thanks to the feeding with milk.

Treatments

Dogmatil: neuroleptic drug indicated in anxiety disorders in adults and behavioral disorders in children. In high doses, it can cause amenorrhea or galactorrhea (abnormal flow of milk from one or two nipples because it is outside the period of milk production) (2).

Chemicals: in 2014, an American study (8) listed chemicals that could cause breast cancer. Gasoline, diesel or even solvents are examples.

Cancer screening: since 2004, screening organized throughout France has invited women aged 50-74 to screening examinations every two years. Detected early, the chances of recovery are 9 in 10.

• Mammography: x-ray of the breasts which allows to visualize with precision their internal structure. In the presence of tumors, mammography can distinguish their malignant or benign character. According to the WHO, mortality would be reduced by 20 to 30% in women over 50 years thanks to this examination.
• Self-examination of the breasts: palpation of the breasts carried out by the women themselves in order to know their breasts and to monitor their appearance. In the event of the appearance of nodules or changes in the size, shape, contour of the breasts or nipple, it is important to consult a specialist.
• Genetic testing: Genetic mutations have been associated with predispositions to developing breast cancer, such as the mutation in the BRCA1 and BRCA210 genes. If there is a family history, a genetic test can be done to determine whether or not the patient is a carrier of such a mutation.

Breast ultrasound: ultrasound imaging technique to visualize the inside of the breasts

Biopsy: a medical examination that involves taking a sample of the breast tumor to determine if it is cancerous or not. May be accompanied by a puncture.

Mastectomy: partial or total removal of the breast performed with the aim of removing the mammary gland. It is practiced in case of breast cancer or for prevention. In this case, the proposal is only made to women with a mutation in the BRCA1 and BRCA2 genes, such as Angelina Jolie. The probability of developing breast cancer before age 70 and then 65 to 85% (11) (compared to 10% in non-carrier women). The operation reduces the risk of developing breast cancer by 90% (12).

Such an operation leaves a scar on the breast which can be a source of psychological trauma in women. On January 12, the Institut Gustave Roussy (Villejuif) performed a mastectomy using a robot for the first time in the world (13). This technique made it possible to incise the skin under the armpit in order to leave a more discreet and less traumatic scar. A surgeon cannot perform such a gesture in good conditions due to a lack of vision and range of motion.

Breast reconstruction:

• After a mastectomy: breast reconstruction can directly follow the removal of the breasts or be performed later, most often at the end of treatments. There are two main methods: the placement of an internal prosthesis (breast implant) or the use of tissues taken from other parts of the body (flap reconstruction). This operation is not systematic, some women choose not to reconstruct their breasts.
• Modification of the volume of the breasts: cosmetic surgery, it appeals to less than 1% of women wishing to modify the volume of their breasts.

Symbol of femininity and seduction, breasts also embody motherhood and breastfeeding.

Chest perception

By men

Object of fantasy, men are generally fascinated by women’s breasts. According to a study (15), for 82% of men questioned, the breasts represent the second favorite part of a woman’s body. In first position is the face (86%).

By women

According to a survey by the British magazine The Daily Mirror (16), 30% of 167 women surveyed say they “hate” their breasts and only 10% are satisfied. Moreover, the breasts are the last physical elements that women like at home (16%), behind the eyes (51%), the mouth and the smile (28%), and the hair (24%) (17) . However, an American study (18) shows that women linger as much as men on the breasts of other women. But in their case, it would be to compare their silhouettes.