Breast Sanjaya Adikari Department of Anatomy

Consists of milk producing glands Glands are modified sweat glands Assist reproduction in women Rudimentary in men Lies in the subcutaneous tissue

Extension transverse – LSB to MAL vertical – 2nd to 6th rib Position of nipples 4th ICS in males 10 cm from AML Size is variable due to the amount of fat surrounding the glandular tissue. Extent of the base is fairly constant

suspensory ligaments of Cooper retro-mammary space posterior capsule Connects the dermis of the skin to the posterior capsule retro-mammary space Contains loose connective tissue posterior capsule Condensation of the membranous layer of superficial abdominal fascia of Scarpa pectoral fascia

Structure 15 – 25 lobes Each lobe drains by its lactiferous duct Lobes consist of many lobules Lobules consist of alveolar ducts Lobules are separated by loose connective tissure Lobes are separated by dense connective tissue

of Cooper 15-25 breast lobes 15-25

Smooth muscles

Resting breast Lobule Alveolar ducts Lined by cuboidal cells Myoepithelial cells between the cuboidal cells and the BM Cyclical changes according to the ovarian cycle

Breast during pregnancy Changes due to oestrogen, progesteron, prolactin etc. Numerous secretory alveoli formed by proliferating alveolar duct epithelium Interlobular connective tissue becomes less Alveoli and ducts get filled with Colostrum Colostrum is a protein-rich fluid containing maternal antibodies Breast during pregnancy

Lactating breast Consists entirely of glandular tissue Alveoli are dilated with milk Interlobular connective tissue disappears Prolactin promotes the production of milk Oxytocin causes contraction of myoepithelial cells and ejection of milk Lactating breast

Blood supply Thoracoacromial trunk

Development of breasts Mammary line or ridge develops at 7 weeks IUL Thickening of epidermis Persists only in thoracic region If persists in other regions cause accessory nipples – common in axillary region Epithelial sprouts formed and canalized

axilla inguinal region

Development ….cont. Lactiferous ducts open into an ‘epithelial pit’ After birth the nipple is formed by proliferation of underlying mesenchyme Persistance of epithelial pit causes inverted nipples. An underlying tumour can also cause nipples to invert Lobule formation occurs only in the female after puberty

Lymph drainage 75% 25%

Lymph drainage About 75% passes to axillary nodes Rest of it mainly passes to parasternal nodes Superficial lymphatics of the breast have connections with the opposite breast

Axillary lymph nodes apical lateral anterior posterior central

Flow of lymph from axillary nodes Jugular lymph trunk Subclavian lymph trunk Right lymph duct

Breast Quadrants lump Upper outer quadrant Bulk of the tissues 4 cm most benign/malignant conditions occur in this quadrant

suspensory ligaments of Cooper dimpling retro-mammary space posterior capsule pectoral fascia

Mammogram Tumour

Tension lines of the skin

Tension lines of the breast surgical incisions Lactiferous ducts Radial incision

Mastectomy Radical mastectomy Modified radical mastectomy whole breast, pec. Major & minor, axillary fat,fascia & LNs preserve pec. Major but remove pec. minor only the breast breast with axillary tissue Radical mastectomy Modified radical mastectomy Simple mastectomy Extended simple mastectomy

Sentinel node/s First node/s to spread of a malignancy Radioisotope labeled method Blue dye injected around the tumour These are assessed during surgery Removed if tumour cells are detected