Repro - Breast Anatomy Flashcards
Where is milk made in the breast and how does it travel to the nipple?
Secretory lobes –> Lactiferous ducts –> Lactiferous sinuses –> Out nipple
All this is supported by fibro-fatty tissue
What kind of gland is the breast tissue?
Highly specialized sweat glands
What are the bony borders of the breast?
From 2/3rd rib to 6th vertically
From sternal edge to midaxillary line horizontally
There is also an Axillary tail to the breast that can stretch towards the axillary fossa
What does the breast sit on?
2/3rd rest on Pectoral fascia (over pec major) & 1/3rd over fascia of serratus anterior
It also sits on the Retromammary bursa which enables some movement
How is the breast attached to the skin?
Attached to the dermis by the Suspensory Ligament of Cooper
This supports the gland
How many lobules of parenchyma are found in the breast?
15-20 in each breast
What tissue type is the nipple?
Collagenous Dense CT
Elastic CT
Smooth muscle bands
(NO fat or hair on nipple)
Where is the nipple in relation to bony landmarks?
Varys but ~ 4th intercostal space
What is the function of the areola?
The skin over the nipple & areola contains lots of sweat & sebaceous glands, they enlarge in pregnancy and secrete an oily material that lubricates the nipple
How do we divide up the breast when describing the location of pathologies e.g. cysts?
4 Quadrants:
- Inferomedial
- Inferolateral
- Superolateral (+axilaly tail)
- Superomedial
Men have breasts too, how are they different?
- Undeveloped
- Small ducts but no lobules or alveoli
- Less Fibro-fatty tissue
When do breasts start developing in the embryo?
Wk4 is when the mamary crests or ridges appear
Where are the mammary crests found?
They extend from axillary to inguinal regions in the embryo, they eventually dissapear except in the pectoral region
How does the mammary crest become a breast?
Most of the mammary crest dissapears leaving the:
- Pectoral part
- -> Primary Mammary Bud
- -> Secondary Mammary Bud
- -> Lactiferous ducts
The ducts then branch inwards until the form glands
List some major embryological defects of the breast:
Polymastia (extra breast)
Polythelia (Extra nipple)
Atelia or Amastia (absence of nipple or breast)
Define Gynaecomastia?
Postnatal development of lactiferous ducts in males
2/3rds of boys in puberty have hyperplasia of breast, not the same thing.
What arteries supply the breast?
Thoraco Acromial Artery
Lateral thoracic artery (From axillary)
Internal thoracic artery
What nerves innervate the breast and what do they do?
Anterior & Lateral cutaneous branches of 4-6th intercostal nerves:
- Sensory to skin of breast
- Symp to blood vessels
- Symp to smooth muscle of nipple
Where does lymph drain in the breast?
Lateral quadrants:
- Mostly to Axillary Nodes
- Some to Supraclavicular or Inf Cervical nodes
Medial Quadrants:
- Parasternal nodes
- Other breast
What is sentinal node biopsy?
When we find a cancer in the breast and remove it we also biopsy the first lymph node (found by injecting radioisotope dye) to assess for spread
What cell types can you see on histology of breast tissue?
Ducts & Acini contain 2 cell types:
- Luminal epithelial cells
- Myoepithelial cells outside
Surrounded by Dense Fibrous Interlobular tissue (Stroma) and Adipose tissue
What happens to the breast pre-puberty?
Some enlargement due to growth of fibrous stroma and fat
But not yet any lobules (ducts havent brancehd much)
What happens to the breast during puberty?
Branching of lactiferous ducts and formation of alveoli
Lipids also accumulate in adipocytes
What happens to the breast after menopause?
Progressive atrophy of the lobules & ducts
The glandular tissue is replaced with fat
How does the breast change during pregnancy? (hist)
Lobules enlarge and acini dilate
The epithelium varies from cuboidal to columnar
What is colostrum?
PRotein rich fluid full of maternal antibodies thats secreted a few days after birth
How does the breast tissue appear during lactation (hist)?
Acini become distended with milk and the septa look very thin. At a high magnification you can see the acini contain eosinophilic material and clear vacuoles
What hormones are released during suckling to stimulate milk production?
Prolactin & OXytocin
How can you diagnose breast pathology?
Mammography & US
Fine Needle Aspiration Cytology
Core Biopsy
Go look at Powerpoint for images of mammography, will be in exam
How might you see a carcinoma of the breast from the outside?
- Skin dimpling
- Abnormal contours
- Oedema of the skin (Peau d’orange sign)
- Nipple retraction / deviation
List some benign tumours of the breast?
Fibroadenoma
Duct PApilloma
Adenoma
CT tumours
What is Paget’s disease of the niple?
Erosion of the nipply that resembes eczema, commonly associated with ductal or invasive carcinoma
