Reproduction Lecture - Breast Anatomy 1 Flashcards
Describe the steps in the development of the breasts?
- Mammary crests or ridges appear during 4th week
- Crests extend from axillary region to inguinal region
- Crests disappear except in the pectoral region
- Primary and secondary mammary buds develop
What are breasts?
They are modified and high specialised sweat glands:
- No special capsule or sheath
- Both males and females have breasts – females are more developed
- Size and shape is the result from genetic, racial and dietary factors
From what ribs do the breasts extend from and to?
- Extent is from 2nd or 3rd rib to 6th rib
- Transverse is sternal edge to midaxillary line
What do the breasts extend from laterally?
- Transverse is sternal edge to midaxillary line
What do the breasts lie on?
- Lies on deep pectoral fascia
What space exists in the breasts?
- Retromammary space exists (bursa)
- Helps some degree of movement
What is the function of the retromammary space?
- Helps some degree of movement
What are the breasts firmly attach to the dermis by?
- Firmly attached to dermis by suspensory ligament of cooper
- Helps support lobules of the gland
What muscles does the breasts rest on?
- 2/3rd of breast rests on pectoral fascia covering pectoralis major
- 1/3rd of breast rests on the fascia covering serratus anterior
Describe the breast structure?
- Nipple
- Prominence of the breast
- Areola
- Pigmented area around the nipple
- Parenchyma
- 15-20 lobules of glandular tissue
- Each lobule drained by lactiferous duct, which opens on nipple
- Each duct has dilated portion called lactiferous sinus
What is the nipple and areola?
- Nipple
- Prominence of the breast
- Areola
- Pigmented area around the nipple
How many lobules of glandular tissue forms the parenchyma of the breasts?
- 15-20 lobules of glandular tissue
What is each lobule of the breast drained by?
- Each lobule drained by lactiferous duct, which opens on nipple
- Each duct has dilated portion called lactiferous sinus
What is the dilated portion of lactiferous duct called?
- Each duct has dilated portion called lactiferous sinus
What intercostal space are the nipples normally in?
Variable, but normally 4th intercostal space
What tissues forms the nipples?
Collagenous dense connective tissue
Elastic fibres
Bands of smooth muscles
Do the nipples contain any fat or hair?
No
What glands are found in the areola?
Numerous sweat and sebaceous glands
What part of the breast enlarges during pregnancy?
Areola
What is the function of the material secreted by sebaceous glands in the areola?
Oily material provides protective lubricant for nipple and areola
What are the 4 quadrants of the breast?
- Superolateral quadrant
- Superomedial quadrant
- Inferolateral quadrant
- Inferomedial quadrant
What is the axillary tail an extension of?
Axillary tail is extension of breast tissue in the supero-lateral quadrant
What are some features of the male breast?
- Rudimentary throughout life
- Formed by small ducts without lobules or alveoli
- Little supporting fibroadipose tissue
- Temporary enlargement in newborn and during puberty
What are examples of breast related pathology?
- Gynaecomastia
- Postnatal development of rudimentary lactiferous ducts in males
- Supernumerery breasts and nipples
- Polymastia – an extra breast
- Polythelia – an extra nipple
- Absence of breast or nipples
- Athelia – absence of nipple
- Amastia – absence of breast
What are the medical terms for:
- an extra breast
- an extra nipple
- Extra breast
- Polymastia
- Extra nipple
- Polythelia
What is the medical term for:
- absence of nipple
- absence of breast
- Absence of nipple
- Athelia
- Absence of breast
- Amastia
The breasts are supplied by what arteries?
Supplied by branches of axillary artery, internal thoracic and some intercostal arteries:
- Thoraco acromial artery
- Lateral thoracic artery
- Internal mammary (thoracic) artery
What are the breasts innervated by?
- Anterior and lateral cutaneous branches of 4-6th intercostal nerves
- Sensory fibres to the skin of breast
- Sympathetic fibres to blood vessels and smooth muscle around nipple
How does breast cancer mainly spread?
Significant as cancer mainly spreads by lymphatic routes:
- Branch extensively
- Do not contain valves
What lymph nodes drain the breasts?
- Axillary lymph nodes 75%
- Drains from lateral quadrants
- Some to supraclavicular or inferior cervical
- Parasternal or to opposite breast
- Drains from medial quadrants
What is the role of the sentinel lymph node biopsy in breast cancer?
- Staging of patients and lymphatic mapping
- Radiolabelled colloid used to locate sentinel node
What does sentinel lymph node mean?
First draining node
What do breast lobes contain?
- Network of glandular tissue made from branching ducts and secretory lobules in a connective tissue stroma
- Connective tissue stroma surrounding lobules is dense and fibrocollagenous, whereas intralobular tissue has loose texture
- Terminal duct lobular unit is the functional milk secretory component of breast
What is the difference between the structure of connective tissue stroma surrounding lobules and the intralobular tissue?
- Connective tissue stroma surrounding lobules is dense and fibrocollagenous, whereas intralobular tissue has loose texture
What is the functional milk secretory component of breast called?
Terminal duct lobular unit
What 2 layers of cells line the ducts and acini of the breasts?
- Luminal epithelial cells
- Myoepithelial cells
What are some age related changes in breasts?
- Prepuberty
- Neonatal breasts contain lactiferous ducts but no alveoli
- Until puberty, little branching of ducts occurs
- Slight breast enlargement due to growth of fibrous stroma and fat
- Puberty
- Branching of lactiferous ducts
- Solid, sphere masses of glandular polyhedral cells (alveoli)
- Accumulation of lipids in the adipocytes
- Post-menopausal
- Progressive atrophy of lobules and ducts
- Fatty replacement of glandular tissue
What happens to the breasts prepuberty?
- Prepuberty
- Neonatal breasts contain lactiferous ducts but no alveoli
- Until puberty, little branching of ducts occurs
- Slight breast enlargement due to growth of fibrous stroma and fat
What happens to the breasts in puberty?
- Puberty
- Branching of lactiferous ducts
- Solid, sphere masses of glandular polyhedral cells (alveoli)
- Accumulation of lipids in the adipocytes
What happens to the breasts post-menopausal?
- Post-menopausal
- Progressive atrophy of lobules and ducts
- Fatty replacement of glandular tissue
What changes can be seen histologically in the breasts during pregnancy?
- Enlarged lobules
- Acini are dilated
- Epithelium vary from cuboidal to low columnar
- Colostrum present - protein rich fluid
What is colostrum?
Protein rich fluid, available until a few days after birth that is rich in maternal antibodies
What is seen in the histology for lactating breast?
- Acini distended with milk
- Thin speta between lobules
- At high magnification
- Acini with oesinophilic materal containing clear vacoules
- Milk production
- Suckling-Neurohormonal reflex
- Prolactin and oxytocin
What are diagnostic methods of breast cancer?
Methods include:
- Imaging
- Mammography and USS
- Fine needle aspiration cytology
- Core biopsy
Breast cancer - epidemiology
(% of all female cancers, incidence)
- 20% of cancers in woman
- Commonest cause of death in woman in 35-55 age group
- 1/9 incidence
What are signs of carcinoma of the breast?
What are some benign tumours of the breast?
- Fibroadenomas
- Duct papillomas
- Adenomas
- Connective tissue tumours
