breast drainage and lymphatic drainage: Flashcards
what are the two main regions of the breast?
- circular body largest part of the breast - axillary tail smaller part
what is the surface anatomy of the breast on the anterior thoracic wall?
- horizontally = from the lateral border of the sternum to the mid axillary line vertically = between the 2nd and the 6th intercostal cartilages
what is the breast superficial to?
- the pectoralis major muscle - the serratus anterior muscle
what is the nipple the areolae sebaceous glands
nipple: smooth muscle fibres the areolae: pigmented skin sebaceous glands : around the areolae these enlarge during pregnancy and secrete a lubricate for the nipples
what are the mammary glands?
- ducts and secretory lobules - alveoli are drained by a single lactiferous duct - All ducts converge at nipple
what is the connective tissue stroma?
- Supporting structure which surrounds the mammary glands - Has a fibrous and a fatty component:
what is fibrous stroma?
- condenses to form suspensory ligaments of cooper - attaches and secures the breast to the dermis and the underlying pectoral fascia
what is the pectoral fascia?
- the base of the breast lies on the pectoral fascia - there is a flat sheet of connective tissue associated with the pectoralis major muscle - It acts as an attachment point for the suspensory ligaments
what is the overall structure of the breast?
- modified sweat gland - under hormonal influence to make milk post partum - made of glandular tissue, fat, ductal and fibrous tissue
how many lobules does the breast have?
- 15- 20 these contain alveoli
what happens during lactation?
- the alveoli produce milk - the milk is carried to the alveoli in the lactiferous ducts - inside the alveoli, there are myoepithelial cells that contract in response to oxytocin to push the milk along - the lactiferous sinuses are duct expansions that are squeezed during suckling
what are the spaces surrounding the lobules?
fat, ligament and connective tissue
what is breast size determined by?
determined by amount of fat not the lobules
compare younger womens breasts to older womens breasts?
younger women = denser less fatty older women = less dense more fatty
structure of a lobule ?
sections of breast branching out of the nipple contains alveoli
structure of a alveoli ?
- tiny hollow sacs lined with milk secreting cuboidal cells surrounded by myoepithelial cells
structure of a lactiferous duct?
Carry milk from the alveoli toward the areola when lactating
structure of a areola?
Dark pigmented area of skin at the centre of the breast
structure of suspensory ligament
Separates lobules, strong, maintains breast shape
what is the vasculature of the medial aspect of the breast?
Internal thoracic artery Branches from Intercostal artery
what is the vasculature of the lateral aspect of the breast?
Lateral thoracic artery
Thoraco-acromia artery
Thoracodorsal artery
intercostal artery
show the vasculature of the breast :
what nerve is breat skin supplied by?
subdermal plexus
communicates with deep parenchymal vessels
what artery does the nipple-areola region receive?
- branch from internal thoracic artery
what branches of intercostal nerves innervate the breast?
T2 - T6
•Anterolateral and anteromedial branches
what nerves supply the upper and lateral parts of the breast?
supraclavicular nerves
what nerve innervates the nipple?
•lateral cutaneous branch of T4
show a diagram of the innervation of the breast
what is the basis of lympathatics?
- arterial blood enters the capillaries
- substances move out of the blood vessel at the arterial end of the capillary into the interstitial fluid
due to high hydrostatic pressure
- Substances move in the blood vessel at the venous end of capillaries using oncotic pressure
- substance moving out > substance moving in
Excess fluid and solutes are removed by draining lymph vessels
the lympth fluid eventually returns to the general blood circulation
what is lymph normally like?
- clear
- odourless
what is the lymph from the small intestine like?
- opaque & milky due to absorption of fats
how does lymph move?
- there is no real direct pump
- the movement of lymph is done via adjacent structures like skeletal muscle, arterial pulses
- valves are also important for unidirectional movement
what are potential causes of an enlarged lymph node?
infection
cancer
tuberculosis
where does the lymphatic system cover?
where are the most lymph nodes?
- covers everywhere apart from the brain
- the largest collection of lymph nodes is found at the bifurcation of the trachea
- Highly extensive lymphatic system in the Head & Neck especially
where does the upper right quadrant drain into?
where does the rest of the brain drain into?
- the upper right quadrant - drains into the right subclavian vein
- the rest of the body - drains into the left subclavian vein
show where the thoracic duct and the right subclavian vein is located?
what are the three groups of lymph nodes that receive lymph from the breast tissue?
- axillary nodes ( 75% )
- parasternal nodes (20%)
- posterior intercostal nodes (5%)
how is the skin of the breast lymphatically drained?
- skin = drains to the axillary, inferior deep cervical and infraclavicular nodes
- the nipple and areola = drains to the subareolar lymphatic plexus.
where do the superficial parts of the breast drain to?
superficial parts of the breast drain to sub areolar plexus
Deep parts of Breast drain to the Sub-mammary plexus
where are the most common sites of breast cancer metastasis ?
- bone
- regional LNs
- the brain
- the lungs
- the liver
what are the lymphatics of the thoracic wall?
lymph drains to the
- parasternal nodes
- Upper & Lower intercostal nodes
- Diaphragmatic nodes
- Superficial nodes
these are all superficial to the organs
how is the incidence and mortality of breast cancer changing?
the incidence is increasing
the mortality is going down
what is a mammogram?
advantages and disadvantages?
- it is an xray
ads: diagnostic and screening
disads:
Ionising radiation
False negative rate of at least 10%
High false positive - over treatment
what is an ultrasound for?
what is an MRI for?
ultrasound - further evaluation of masses
- measures the size and location of the mass
- it shows the difference between a solid mass and a cyst filled with fluid
the MRI is for further evaluation of the tumor
this is for pre-surgical evaluation
there is good soft tissue differentiation
