Breasts are glands that have an extremely variable morphology, i.e. different volume, elasticity, etc. They are particularly sensitive to hormonal secretions which cause them to change during menstruation, pregnancy, and menopause. The breast may be small and insufficiently developed (breast hypoplasia) or voluminous and thick (breast hypertrophy). The breast may also collapse due to pregnancies, hormonal changes and weight (breast ptosis).
Since they undergo changes in life and take many different shapes and sizes, they don’t always match the figure or wishes of the patient.