Anatomy

Authors Mia Demant, MD, Magnus Balslev Avnstorp, MD, Mia Steffensen, MD, Tine Damsgaard, MD, PhD, Professor

The breast consists of a milk-producing mammary gland (green), enclosed by a skin envelope (yellow), resting on its breast footprint (blue). The footprint rests on the pectoral muscles and anterior thoracic wall. The mammary gland consists of adipose tissue (fat), milk-producing lobules and milk ducts leading the milk to the nipple-areola complex.

The normal breast

Formed like af bell or a tear drop. Lesser fullness in the top, heavier in the bottom. The areola complex with nipples point forward and a little to the sides.

The standard breast measures

On a young woman with a medium sized breast (300-500 ml) the measures should be:

• Jugulum (sternal notch) – Nipple Distance: 19-21 cm
• Medio clavicular point – Nipple Distance: 19-21 cm
• Nipple – Inframammary fold Distance: 5-6 cm
• Nipple – sternal bone distance: 9-11 cm

Pathophysiology

The patient may suffer from a congenital disease resulting in macromastia, micromastia or asymmetry of the breast or thorax.

All breasts will over time be influenced by changing weight, pregnancy, aging of the skin and/or suspensive connective tissue caused by the gravity.

The patient may have been through a massive weight loss (following bariatric surgery or by changes in her lifestyle). As a result, the skin envelope is stretched compared to the now smaller mammary gland.

The abnormal breast

• Breast Atrophy Shrinkage of the breast commonly occurs in women during menopause with decreasing estrogen levels.
• Breast Hypertrophy Enlargement of the breast tissue, often bilaterally. Occurs during pregnancy or due to medications and can cause neck- and back-pain.
• Tuberous breasts Congenital abnormality where the breast fails to develop during puberty, with herniation of the areolar complex.
• Breast Asymmetry A common difference in form, position or volume.
• Pectus Excavatum Chest wall deformity where ribs and sternum grow abnormality, causing a concave appearance in the anterior chest wall.
• East-west asymmetry Nipples pointing outward in opposite directions.

Breast ptosis

• Grade I (Mild ptosis/sagging) Nipple at the level of the IMF and above most of the lower breast tissue.
• Grade II (Moderate ptosis/sagging) Nipple below the IMF but higher than most of the breast tissue.
• Grade III (Advanced ptosis/sagging) Nipple below the IMF and at the level of maximum breast downwards projection.
• Pseudoptosis Nipple located either at or above the IMF. The lower half of the breast sags below the fold. Often seen when a woman stops nursing, as her milk glands atrophy.