Breast anatomy Flashcards
Describe the normal anatomy and histology of the breast.
Describe the lymphatic drainage of the breast and mode of lymphatic spread in breast disease.
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The breast extends from which ribs vertically
And transversely lies between what points
2nd - 6th
Sternal edge and mid-axillary line
What small part of the breast extends towards the axillary fossa
Axillary tail of spence
2/3 of the breast lies on what fascia
Other 1/3 lies on what fascia
Pectoral fascia covering pec major
Fascia covering serrates anterior
The breasts are firmly attached to the dermis by what ligament
Suspensory ligament of Cooper
Each breast contains 15-20 lobules
Each lobule is drained by a
lactiferous duct which opens on the nipple
Each lactiferous duct has a dilated portion called the
lactiferous sinus
Areola contains what
Sweat and sebaceous glands which secrete oily material that provides a protective lubricant for the nipple and areola
Surface marking of the nipple
4th intercostal space (but varies)
4 quadrants of the breast
- superolateral
- superomedial
- inferolateral
- inferomedial
Which quadrant does the axillary tail (extension of breast tissue) extend into
Superolateral
Why are male breasts not prominent
Very little fat tissue
Embryonic origin of breasts
Mammary crests/ridges appear in first 7 weeks which extend from axilla to inguinal region; the crests shorten over time and become recognisable in the thoracic region
Milk linesform as thickenings of theepidermisof the mammary ridge then nipples usually grow along the milk line
What’s gynaecomastia + at what stage of life does it affect males
Enlarged breasts in males due to postnatal development of lactiferous ducts
Puberty and older men - usually due to imbalance in hormones (lower testosterone, higher oestrogen)
Define
- polymastia
- polythelia
- athelia
- amastia
Extra breast
Extra nipple
Absence of nipple
Absence of breast
Arterial supply to
- medial breast (1)
- lateral breast (4)
Internal thoracic - from subclavian
Lateral thoracic and thoracoacromial branches - from axillary
Lateral mammary branches - from post. intercostals
Mammary branch - from ant. intercostal
The veins of the breast correspond with the arteries, draining into which 2 veins
Axillary and internal thoracic
Innervation of breasts
anterior and lateral cutaneous branches of the 4th to 6th intercostal nerves (both SENSORY + AUTONOMIC)
Lymphatic drainage of the breast (3)
Axillary nodes (75%) - drains lateral quadrant
Parasternal nodes - drains medial quadrant
Posterior intercostal nodes (5%)
Mode of lymphatic spread in breast disease
Mostly to the axillary nodes then from there can spread to liver, lungs, bones, brain
What is a sentinel lymph node + clinical significance
first lymph node to which cancer cells are most likely to spread from that primary tumour
Biopsy of the sentinel lymph node is carried out
The soft tissue of the breast consists of lobes which is glandular tissue consisting of ducts and secretory lobules within a connective tissue stroma (separating it from other lobes)
The terminal duct lobular unit is what
functional milk secretory component of the breast
Ducts and acini of the breasts are lined by 2 layers of cells - name these
Luminal epithelial and myoepithelial cells
How does age change the development of the breast
- prepuberty
- puberty
- post-menopausal
Lactiferous ducts but no alveoli, little branching of the ducts, little fibrous storm and fat
Branching of lactiferous ducts, alveoli develop as solid spherical masses, lipids accumulate
Atrophy of lobules and ducts, fatty replacement of glandular tissue
Changes in a breast during pregnancy on histology
Enlarged lobules Dilated acini (large white blobs)
Changes in a lactating breast on histology
Acini VERY DISTENDED with milk
Thin septa between lobules
To assess a suspected breast cancer a triple assessment is carried out - what does this involve
Clinical examination
Imaging - mammogram and ultrasound scan
Biopsy
Benign breast tumours
Fibroadenomas
Duct papillomas
Paget’s disease of the nipple
