Female breast anatomy

Breasts come in all different shapes and sizes but, generally speaking, the anatomy remains the same from woman to woman. Breasts are situated on the pectoralis major muscles which are found on the chest of both women and men.

Female hormones (such as oestrogen) cause a woman’s breast to develop and grow during puberty, whilst male hormones (such as testosterone) stop the breast from growing. In women, the fully developed breast extends from the second to the sixth rib and from your collar bone to your breast bone.

Breasts are made up mainly of different types of tissue and fat. They contain ligaments, milk ducts and glands but no muscles. The Cooper’s ligament holds the breast in place and provides firmness. Size and dimensions of breasts are different in all women but as an average, each breast tends to weigh between 1lb and 2.2lb. The tissues, ducts and fat of the breast are covered with skin and ‘topped off’ with the nipple and the areola (the circle of darker skin that surrounds the nipple). Both the nipple and areola can vary in colour from light pink to dark brown.

The firmness of a woman’s breast is determined mainly by the ratio of fat and tissue they contain. Breasts tend to change size and shape at various times throughout a woman’s life: during puberty, pregnancy, breastfeeding and the menopause for example. In the shorter term, weight loss and hormones can also affect the appearance of breasts.

Of course, the main function of a woman’s breasts is to provide nourishment for her babies. Therefore, they contain a system of milk ducts and mammary glands which carry milk via a series of ‘lobes’ into the nipples, ready for the suckling baby.

Here’s a rundown of the different parts of the breasts – and what they do:

• Adipose tissue – this type of tissue makes up the bulk of the breast and also contains the milk ducts.
• Cooper’s ligament – these ligaments hold up and support the breast and keep the tissues in place. If these ligaments stretch or become out of shape, the breasts may sag and lose their firmness. Once this happens, it is irreversible
• Milk ducts – the network of milk ducts within the breasts work together with a lactogenic hormone to produce milk during the last month of pregnancy and once baby is born.
• Nipple – The nipple is the outermost part of a breast. It contains lots of nerve endings and is the part of the breast that a baby suckles in order to ‘let down’ milk.
• Areola – the area which surrounds the nipple. It contains sebaceous (oil-producing) glands to keep the nipple lubricated during breastfeeding.