breast - normal anatomy Flashcards
at which point of fetal development do mammary crests/ridges appear
week 4
location of mammary crests
extend from axillary region to inguinal region
crests usually disappear except in the pectoral region
stages of breast development
1y mammary buds
2y buds
lactiferous ducts and their branches
function of breasts
2y sexual feature of F
source of nutrition for neonates
present in a rudimentary form in M
site of malignant change - up to 1/10 women
general features of breasts
modified and highly specialised sweat glands - tubuloacinar
no special capsule or sheath
present in M and F, well developed in F
breast size and shape result from genetic, racial and dietary factors
breast - vertical and transverse location
vertical - 2nd/3rd rib - 6th rib
transverse - sternal edge to midaxillary line
what is the axillary tail of spence
small part of breast may extend towards axillary fossa
what is the function of the retromammary space (bursa)
helps some degree of movement
breast relations
2/3 of breast rests on pectoral fascia covering pec. maj
1/3 rests on the fascia covering serratus anterior
how is the breast attached to the dermis
firmly attached by suspensory ligament of cooper - helps support the lobules of the gland
breast structure - nipple
nipple - prominence of the breast
breast structure - areola
pigmented area around the nipple
rich in sebaceous glands - not associated with the hair follicle as in other regions
breast structure - lobules
each breast contains 15-20 lobules of glandular tissue (parenchyma)
each lobule is drained by a lactiferous duct - opens independently on the nipple
each duct has a dilated portion - lactiferous sinus
does the nipple contain any fat or hair
no fat or hair
what tissue makes up the nipple
collagenous dense connective tissue
elastic fibres
bands of smooth muscle
lactiferous ducts and the nipple
the tips of the nipples are fissured with lactiferous ducts opening into them
position of the nipple
variable or 4th IC space
glands on the surface of the areola
skin covering the nipple and areola contains numerous sweat and sebaceous glands
changes to the areola during pregnancy
enlarges
secretions from the areola
oily material secreted by the sebaceous gland provides a protective lubricant for the nipple and areola
breast quadrants
divided into 4 quadrants for anatomical location and description of pathology
superomedial, inferomedial, inferolateral, superolateral
axillary tail is an extension of the breast tissue in the superolateral quadrant
describe the male breast
rudimentary throughout life
formed by small ducts w/o lobules or alveoli
little supporting fibroadipose tissue
temporary enlargement in newborn and during puberty
define gynaecomastia
postnatal development of rudimentary lactiferous ducts in males
during midpuberty ~2/3 of boys develop varying degrees of hyperplasia of the breasts
define polymastia
an extra breast
define polythelia
extra nipple
define athelia/amastia
absence of nipple/breast
what arteries supply the breasts
branches of axillary a., internal thoracic a., and some IC a.
thoraco-acromial a.
lateral thoracic a.
internal mammary (thoracic) a.
nerves of the breast
anterior and lateral cutaneous branches of 4-6th IC n. - convey sensory fibres to the skin of the breast
also carry sympathetic fibres to the blood vessels and smooth muscle around the nipple
lymphatic drainage of the breast - clinical significance
great clinical significance - metastatic dissemination occurs primarily by the lymphatic routes
breast lymphatics branch extensively and don’t contain valves
lymphatic drainage of the breast
>75% of lymph from lateral quadrants –> axillary LNs
some lymph may drain directly to supraclavicular or inferior cervical nodes
lymph from medial quadrants - parasternal or to opposite breast
what is a sentinal lymph node
first draining node
role of sentinal lymph node biopsy in breast cancer
lymphatic mapping and staging of patients
radiolabelled colloid is used to locate the sentinal node
blue dye is injected at the time of surgery
combination of radioisotope and dye provides most accurate means of localising the node
describe the breast soft tissue
lobes which contain a network of glandular tissue consisting of branching ducts and secretory lobules in a connective tissue stroma
connective tissue stroma = dense and fibrocollagenous
intralobular tissue = loose texture
what is the functional secretory component of the breast
terminal duct lobular unit is the functional milk secretory component
what breast tissue is shown here
describe the histology features
normal breast histology
extensive branching duct system
surrounded by dense fibrous interlobular tissue (F) and adipose tissue (A)
ducts and acini are lined by 2 layers of cells - luminal epithelial cells (E) and myoepithelial cells (M)
age related changes in breasts - prepuberty
neonatal breasts contain lactiferous ducts but no alveoli (acini)
until puberty, little branching of the ducts occurs
slight breast enlargement reflects the growth of fibrous stroma and fat
age related changes in breasts - puberty
branching of lactiferous ducts
solid, spheroidal masses of granular polyhedral cells (alveoli)
accumulation of lipids in the adipocytes
age related changes in breasts - postmenopausal
progressive atrophy of lobules and ducts
fatty replacement of glandular tissue
what breast histology is shown here - label the letters
during pregnancy
Lo - lobules
S - septa
A - acini
E - epithelial cells
enlarged lobules, acini are dilated, epithelium vary from cuboidal to low columnar
what is colostrum
protein rich fluid, available a few days after birth
rich in maternal antibodies
what breast histology is shown here - identify the labels
lactating breast
acini distended with milk
thin speta (S) between the lobules
image b - higher power, acini with eosinophilic material containing clear vacuoles
milk production - suckling - neurohormonal reflex - prolactin and oxytocin
diagnostic methods for breast cancer
mammography and US
fine needle aspiration cytology
core biopsy
how common is breast cancer
20% of all cancers in women
commonest cause of death in women aged 35-55y/o
in UK any women has 1/9 chance of developing breast cancer
what is shown here
CIS - carcinoma in situ
Ca - cluster of malignant epithelial cells invade into the normal stroma (S)
what are some signs of breast cancer
skin dimpling
abnormal contours
edema of skin (peau d’orange sign)
nipple retraction and deviation
benign breast tumours
fibroadenomas
duct papillomas
adenomas
connective tissue tumours
Paget’s disease of the nipple
what is Paget’s disease of the nipple
erosion of the nipple resembling eczema
associated with ductal or invasive carcinom
