normal anatomy of the breast Flashcards
when do mammary crests or ridges appear
4th week
where do mammary crests extend to
These crests extend from axillary region to inguinal region
The crests usually disappear except in the pectoral region
what do primary mammary buds extend into
Primary mammary buds – Secondary buds – lactiferous ducts and their branches
who are breasts found in and what is their general function
Secondary sexual feature of females
Source of nutrition for the neonates
Present in a rudimentary form in males
Site of malignant change in as many as 1 in 10 women
what are general features of breasts
Modified and highly specialized sweat glands
No special capsule or sheath
Both Males & females have breasts
Well developed in females
Breast size and shape result from genetic,racial, and dietary factors
where is the breast located
Extent: Vertical: 2nd or 3rd rib – 6th rib
Transverse: Sternal edge to midaxillary line
Lies on the deep pectoral fascia
Axillary tail (of spence) or process – a small part of
breast may extend towards axillary fossa
Retromammary space (bursa) – helps some degree of
movement
what anatomical components are related to the breast
2/3rd of the breast rests on the pectoral fascia covering pectoralis major
1/3rd of the breast rests on the fascia covering serratus anterior
Firmly attached to the dermis by suspensory ligament of cooper – help support the lobules of the gland
nipple
Prominence of the breast
areola
Pigmented area around the nipple
how many lobules of glandular tissue does each breast contain
Each breast contains 15-20 lobules of glandular tissue (parenchyma)
what is each lobule drained by
a lactiferous duct – opens independently on the nipple
Each duct has a dilated portion – lactiferous sinus
what does the nipple contain and where is it located
No fat or hair
Contains collagenous dense connective tissue, elastic fibres and bands of smooth muscle
The tips of the nipples are fissured with lactiferous ducts opening into them
Position : variable or 4th intercostal space
what is the areola and how does pregnancy affect it
Skin covering the nipple and areola contains numerous sweat & sebaceous glands
Enlarge during pregnancy
Oily material secreted by the sebaceous gland provides a protective lubricant for nipple and areola
what quadrants are the breast divided into
For anatomical location and description of pathology (cysts and tumours) the breast is divided into 4 quadrants.
The axillary tail is an extension of breast tissue in the supero-lateral quadrant
SUPEROLATERAL
SUPEROMEDIAL
INFEROLATERAL
INFEROMEDIAL
what are components of the male breast
Rudimentary throughout life
Formed by small ducts without lobules or alveoli
Little supporting fibroadipose tissue
Temporary enlargement in newborn & during puberty
what is gynaecomastia
Postnatal development of rudimentary lactiferous ducts in males
During midpuberty about 2/3rd of boys develop varying degrees of hyperplasia of the breasts
what are supernumerary breasts and nipples
Polymastia –An extra breast
Polythelia – An extra nipple
what is athelia or amastia
Absence of nipple or breast
what is the blood supply to the breast
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 nerves of the breast
Anterior and lateral cutaneous branches of 4-6th intercostal nerves
They convey sensory fibers to the skin of the breast
They also carry sympathetic fibres to the blood vessels and to the smooth muscle around the nipple
what is lymphatic drainage of the breast
Great clinical significance because metastatic dissemination occurs primarily by the lymphatic routes
Breast lymphatics branch extensively and do not contain valves
Most lymph (more than 75%) from lateral quadrants – axillary lymph nodes
Some lymph may drain directly to supraclavicular or inferior cervical nodes
Lymph from medial quadrants – parasternal or to opposite breast
Role of sentinel lymph node (first draining node) biopsy – Breast Cancer
lymphatic mapping & staging of patients
A radiolabelled colloid is used to locate the sentinel node
At the time of surgery, a vital blue dye is injected
Combination of rodioisotope and dye provides most accurate means of localizing the node
what makes up the soft tissue of the breast
Made up of lobes which contains a network of glandular tissue consisting of branching ducts and secretory lobules in a connective tissue stroma.
The terminal duct lobular unit is the functional milk secretory component of the breast
The connective tissue stroma that surrounds the lobules is dense and fibrocollagenous, whereas intralobular tissue has a loose texture
what is the histological appearance of a normal breast
Extensive branching duct
system
Surrounded by dense fibrous
interlobular tissue (F) & adipose
tissue (A)
Ducts & acini are lined by two
layers of cells – Luminal
epithelial cells (E) &
myoepithelial cells (M)
prepubertal breast changes
Neonatal breast contain lactiferous ducts but no alveoli
Until puberty, little branching of the ducts occurs
Slight breast enlargement reflects the growth of fibrous stroma and fat
pubertal breast changes
Branching of lactiferous ducts
Solid, spheroidal masses of granular polyhedral cells (alveoli)
Accumulation of lipids in the adipocytes
post menopausal breast changes
Progressive atrophy of lobules and ducts
Fatty replacement of glandular tissue
what are diagnostic methods for the breast
Imaging –Mammography and Ultrasound
Fine needle aspiration cytology
Core biopsy
what are examples of benign breast tumours
Fibroadenomas
Duct papillomas
Adenomas
Connective tissue tumours
what is Paget’s disease of the nipple
Erosion of the nipple resembling eczema
Associated with ductal or invasive carcinoma
