Breast imaging – Mammography interpretation – Understanding the normal mammogram – Normal mammogram
A clear understanding of the normal appearance of breast tissue patterns is important to detect an abnormal finding on mammography.
Normal breast anatomy on mammography
In a mammographic image the following features should be examined carefully before reporting:
- Skin: The normal skin of the breast is usually 0.5–2 mm thick. It becomes thicker to form the areola surrounding the nipple. The nipple is centred in the lower portion of the breast.
- Adipose tissue: The amount of fat in the breast varies with the body mass index and age of the woman.
- Fibroglandular portion of the breast: The glandular tissues include the major ducts with their tributaries and the TDLUs forming the lobes of the breast. The branches of the major ducts overlap and do not follow boundaries.
- Peripheral zone: This is a zone 1 cm wide that lies just beneath the subcutaneous fat and in front of the retromammary fat. More than 70% of breast cancers develop in this zone.
- Pectoralis major and pectoralis minor muscle: seen on the MLO view.
- Axillary lymph nodes: should be of normal size and with normal central fatty sinus.
- Retromammary fat: This is a clear zone, which does not show any density on a normal mammogram.
Mammograms of the normal breast showing the anatomy
Click on the pictures to magnify and display the legends
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