Anatomy & Physiology Flashcards
What are Cooper’s ligaments?
Thin sheets of fascia that extend like a mesh through the breast parenchyma attaching to the dermis and superficial and deep fascias layers.
Provide support to the breast.
Where does the breast extend to superiorly, inferiorly, medially and laterally?
Superior: 2nd rib
Inferior: 6th rib
Medially: lateral edge of body of sternum
Laterally: mid-axillary line
At the superior-lateral aspect the breast extends into the axilla along the lower border of the pectoralis major -> known as the axillary tail (tail of Spencer)
What is the vascular supply to the breast? (3 arteries)
The breast is supplied by an anastomotic network formed from:
1) branches of the axillary artery
2) perforating branches of intercostal muscles
3) perforating branches of the internal mammary artery
What are the two main groups of lymph nodes which drain the breast and how is the drainage split?
2 groups - the axillary nodes and the internal mammary nodes
75% of the drainage goes to the 20-30 axillary nodes which are anatomically subdivided into 5 groups but for surgical and pathalogical purposes split into 3 levels:
Level 1: nodes inferior to pectoralis minor
Level 2: nodes behind pectoralis minor
Level 3: nodes above pectoralis minor
Most of the remaining lymph drains to the internal mammary nodes. Any part of breast can drain to any group but generally tumours in the medial part of the breast are more likely to drain to the internal mammary nodes than those in the lateral breast.
In breast histology, what is the TDLU?
TDLU = terminal duct lobar unit
The TDLU consists of a lobule (milk-producing gland) and it’s associated terminal duct. A lobule takes the form of a cluster of multiple blind-ending ductules surrounded by specialised connective tissue.
What histological part of the breast is breast cancer thought to originate?
The TDLU (terminal ductal lobar unit)
What is the arrangement of the breast before puberty?
Before puberty, male and female breasts are identical and consist of multiple rudimentary blind-ending ducts arranged radially and converging towards the nipple.
What changes occur in the breast at puberty?
At puberty, under the influence of hormones (predominantly oestrogen but also progesterone):
- proliferation and branching of the ductal system
- formation of solid masses of cells at the duct terminations (which are to become the future breast lobules)
When does fully functional development of the breast occur? What happens?
At pregnancy and lactation - due to the hormonal changes.
At pregnancy:
- ductal and lobular proliferation
- glandular tissue now occupies proportionally more of the breast
- increased pigmentation of the nipple and areolar can occur
At lactation:
- lactation only becomes established if the baby suckles regularly
What are the changes to the breast after menopause?
- Atrophy of the glandular elements
- Decrease in the amount of fibrous tissue within the breast
- Fatty tissue tends to predominate
Which two hormones are involved in lactation after pregnancy?
Prolactin:
- lactogenic
Oxytocin:
- released in response to suckling
- causes contraction of myoepithelial cells increasing the supple of milk
- mediates the secretion of prolactin
Name 2 complications of breast surgery.
In axillary surgery - damaging axillary long thoracic nerve can cause damage to serrations anterior muscle causing winged scapula and difficulty getting from sitting to standing.
When removing lymph nodes - can get lymphadenopathy in arm due to disrupted lymphatic drainage.
