Thorax 1 - Breast Anatomy Flashcards
what three muscles is the breast anatomically related/ close to?
pectoralis major (2/3 of breast)
serratus anterior (1/3 of breast)
rectus abdominus (overlaps with upper part of rectus sheath)
what ribs does the breast overlie vertically?
2nd to 6th ribs
what are the two main types of tissue in breast tissue?
connective tissue
glandular tissue
what is the primary component of the breast tissue during lactation?
glandular tissue - composition increases in lactating women
in non-lactating women, what is the predominant composition of breast tissue?
fatty connective tissue
what role do the glandular tissue and ducts play in the breast?
glandular tissue in the breast contains ducts & secretory lobules - converge into 15-20 lactiferous ducts around the nipple that open independently
what happens to the breast tissue composition during lactation?
increase in proportion of glandular tissue compared to non-lactating women
what key ligament does the connective tissue of the breast? why is it important?
suspensory ligament of Cooper - separates the breast lobules & is continuous with the skin and deep fascia
what happens when the suspensory ligaments of Cooper are shortened or tethered? what conditions might this indicate?
shortened/tethered = leads to dimpling of the breast
indicative of breast carcinoma or lymphatic obstruction
role of the areola in the breast?
pigmented area surrounding the nipple - provides lubrication during lactation
what is the primary tissue type in the breast during lactation?
a) Glandular tissue
b) Fatty connective tissue
c) Cartilage
d) Muscle tissue
A: glandular tissue
which structure in the breast separates the lobes and is continuous with the skin and deep fascia?
a) Suspensory ligament of Cooper
b) Lactiferous duct
c) Mammary gland
d) Areola
A: suspensory ligament of Cooper
what does dimpling of the breast usually indicate?
a) Increased glandular tissue
b) Shortening or tethering of the suspensory ligaments of Cooper
c) Lactation
d) A decrease in fatty connective tissue
B: shortening or tethering of the suspensory ligaments of Cooper
WHAT structure of the breast contains numerous sebaceous glands that enlarge during pregnancy?
areola - sebaceous glands provide lubrication during lactation
each lobule of the breast is drained by WHAT structure?
lactiferous duct
what artery supplies the medial part of the breast? what artery does it arise from?
internal thoracic/mammary artery (+ its perforating branches)
arises from the subclavian artery
what arteries supply the lateral part of the breast? what artery do these arise from?
mammary branches from:
1. lateral thoracic artery (from axillary artery)
2. posterior intercostal arteries (from thoracic aorta)
3. anterior intercostal arteries (from internal thoracic artery)
which arteries provide mammary branches to the anterior part of the breast? what artery does it arise from?
anterior intercostal arteries - arise from the internal thoracic artery
what role do the posterior intercostal arteries play in supplying the breast? what artery does this arise from?
mammary branches supply lateral part of the breast - arises from the thoracic aorta
what artery do the anterior intercostal arteries arise from? what does it supply?
internal thoracic artery - supply the anterior part of the breast via its mammary branches
which artery gives medial mammary and perforating branches to the medial part of the breast?
internal thoracic/ mammary artery
TRUE/FALSE: the medial part of the breast is supplied by the axillary artery
FALSE - it’s supplied by the internal thoracic artery (branch of the subclavian artery)
TRUE/FALSE: the lateral thoracic artery provides mammary branches to the lateral part of the breast
TRUE
TRUE/FALSE: the posterior intercostal arteries arise from the thoracic aorta and give rise to lateral mammary branches
TRUE - go on to supply the lateral part of the breast
which artery supplies the medial part of the breast?
a) Lateral thoracic artery
b) Internal thoracic (mammary) artery
c) Axillary artery
d) Subcostal artery
B: internal thoracic/mammary artery - its medial mammary & perforating branches
from where do the lateral mammary branches of the breast arise?
a) Internal thoracic artery
b) Lateral thoracic artery and thoracoacromial arteries
c) Posterior intercostal arteries
d) Subclavian artery
B: lateral thoracic artery & thoracoacromial arteries - supply lateral part of breast
which of the following arteries primarily supplies the lateral mammary branches of the breast?
a) Internal thoracic artery
b) Lateral thoracic artery
c) Thoracoacromial artery
d) Subcostal artery
B: lateral thoracic artery
describe the arterial supply to the different parts of the breast (medial, lateral & anterior) and where these arteries arise from
medial part of breast: perforating branches of the internal thoracic artery - arise from the subclavian artery
lateral part of breast:
- mammary branches of lateral thoracic artery arise from axillary artery
- mammary branches of posterior intercostal arteries - arise from thoracic aorta
anterior part of breast: mammary branches of anterior intercostal artery - arises from internal thoracic artery
TRUE/FALSE: the anterior intercostal artery arises from the thoracic aorta
FALSE - arises from the internal thoracic artery (the posterior intercostal arteries arise from the thoracic aorta)
where is the circular venous plexus found? what does it drain into?
found at the base of the nipple - drains into the axillary and internal thoracic veins
TRUE/FALSE: venous drainage of the breast goes into the subclavian vein
FALSE - goes from the circular venous plexus around the nipple to the axillary & internal thoracic veins
describe venous drainage of the breast
circular venous plexus at the base of the nipple drains into the axillary & internal thoracic veins
which nerve provides sensory innervation to the nipple and areola?
4th intercostal nerve mainly (variations from 3rd to 5th intercostal nerves)
what area of the breast do the 2nd-6th intercostal nerves supply?
anterior skin of breast
which lymph nodes receive the majority of the breast’s lymphatic drainage? how much?
axillary lymph nodes - 75% of drainage
where are the parasternal lymph nodes located and what do they drain?
deep to the anterior thoracic wall - drain the medial portions of the breast & anterior thoracic wall
what artery are the parasternal lymph nodes located along?
internal thoracic artery
how much lymphatic drainage of the breast do the parasternal nodes receive?
20%
what nodes receive 5% of breast lymphatic drainage?
posterior intercostal nodes
what are the 5 groups of axillary lymph nodes?
pectoral/anterior
subscapular/posterior
brachial/lateral
central
apical
which group of axillary lymph nodes drains the upper limb?
brachial/lateral group
where are the central lymph nodes located in the axilla? what do they collect lymph from?
in the centre of the axilla/near the base - collect lymph from pectoral, subscapular, and brachial groups
what happens when lymphatic drainage from the breast is blocked due to breast cancer?
skin dimpling or breast tissue tethering
which axillary lymph nodes are located near the lower border of the subscapularis muscle? where do they collect lymph from?
subscapular/posterior group - lymph from the posterior thoracic wall
TRUE/FALSE: The majority of breast lymphatic drainage drains into the parasternal lymph nodes
FALSE - 75% to the axillary LNs; 20% to parasternal nodes
which lymph node group drains the anterior thoracic wall and most of the breast?
a) Pectoral (anterior) group
b) Subscapular (posterior) group
c) Brachial (lateral) group
d) Apical group
A: pectoral/anterior group
which lymphatic drainage pathway is most likely to be blocked in breast cancer, leading to skin dimpling?
a) Parasternal lymph nodes
b) Abdominal lymph nodes
c) Axillary lymph nodes
d) Posterior intercostal nodes
C: axillary LNs
which of the following lymph node groups primarily drains the medial aspect of the breast and anterior thoracic wall?
a) Axillary lymph nodes
b) Parasternal lymph nodes
c) Posterior intercostal nodes
d) Subscapular lymph nodes
B: parasternal LNs
the apical lymph nodes of the axilla ultimately drain lymph into which major lymphatic structure?
a) Subclavian lymph trunk
b) Thoracic lymphatic duct
c) Right lymphatic duct
d) Internal thoracic vein
A: subclavian lymph trunk - apical LN collects lymph from all the other axilla groups first
what happens during direct muscle/skin infiltration by breast cancer?
cancer invades underlying muscles - e.g. pec major - or skin
muscle invasion makes the skin appear fixed/ immobile; skin invasion causes dimpling or tethering
what symptom is commonly caused by skin invasion in breast cancer? why?
dimpling/tethering of the skin due to involvement of the suspensory ligaments (of Cooper)
which lymph node group is the most common route for breast cancer metastasis?
axillary LNs
in advanced breast cancer, where can metastases spread via the bloodstream?
lungs, bones, liver, brain
TRUE/FALSE: the primary lymphatic route for breast cancer metastasis is through the brachial lymph nodes
FALSE - it’s through the axillary LNs
TRUE/FALSE: skin dimpling caused by breast cancer is due to the invasion of subcutaneous tissues
TRUE
which of the following is a common sign of breast cancer skin invasion?
a) Enlargement of the lymph nodes in the axilla
b) Fixed or immobile breast due to muscle invasion
c) Dimpling or tethering of the skin
d) Protrusion of the nipple
C: dimpling or tethering of the skin
breast cancer can spread through the bloodstream to all of the following organs EXCEPT:
a) Lungs
b) Bones
c) Liver
d) Spleen
D: spleen
