Breast Anatomy Flashcards
What is breast tissue?
A highly modified sweat gland
Where does the breast extend vertically?
2/3rd to 6th rib
Where does the breast extend horizontally?
From sternal edge to midaxillary line
What does the breast lie on?
The Deep Pectoral Fascia
1/3rd lies on the Fascia over the serratus anterior instead
What part of the breast extends towards the axillary fossa?
Axillary Tail/process
What allows movement of the breast?
The retromammary bursa/space
What holds the breast to the skin?
Suspensory ligament of cooper
Supports the lobules by firmly anchoring them to the dermis
How do breast secretions get from lobules to the surface?
Each lobule drained by a lactiferous duct –> Dilated lactiferous sinus –> Opens individually onto the nipple
At what level are the nipples?
4th intercostal space (though highly variable)
How do we divide up the breast when describing locations of abnormalities?
Into 4 quadrants:
Superolateral, superomedial etc.
What different about the male breast?
Made up of small ducts without lobules or alveoli and little fibroadipose support tissue
How do breasts develop?
4th wk = mammary crests appear from axillary to inguinal region
Crests disappear (except in pectoral region)
Primary mammary buds –> 2nd* buds –> Lactiferous ducts & branches
List the major Developmental abnormalities of the breast
Gynaecomastia
Polymastia (extra breast) & polythelia (extra nip)
Athelia or Amastia
What arteries supply the breast?
Branches of axillary, internal thoracic and intercostal arteries:
- Thoracoacromial art
- Lateral thoracic artery
- Internal mammary art
Where do the breasts get sensory fibres from?
Ant & Lat cutaneous branches of 4-6th intercostal nerves (so T4-6)
Where do breasts get sympathetic supply to the blood vessels and smooth muscle of nips?
Also from the ant & lat cutaneous branches of the 4-6th intercostal nerves
Where does lymph from the breasts go?
Lateral –> Axillary & some supraclavicular
Medial –> Parasternal or opp breast
How do we look for lymphatic spread in breast cancer?
Sentinel node biopsy
Inject a radiolabelled colloid & dye into breast and trace it to the first node
How do breasts change at puberty?
This is when the alveoli form and lactiferous ducts branch
Also accumulate lipids
How do breasts change at menopause>?
lobules/ducts progressively atrophy and the glandular tissue is replaced by fat
How do breasts change during pregnancy?
Lobules enlarge
Acini dilate
Milk production
What tests do we have for breast pathologies?
Mammography & Us
FNA cytology
Core biopsy
Classic signs of breast carcinoma?
- dimpling
- Abnormal contours
- Nipple retracted or deviated
- Skin Oedema (orange peel)
