Gross Anatomy and Development of the Breast

Vocabulary flashcards covering gross anatomy, vasculature, lymphatics, innervation, embryology, and clinical anomalies of the breast.

Breast

Paired, hemispherical mammary glands located in the superficial fascia of the anterior thoracic wall.

Mammary gland

A modified sweat gland specialized for milk secretion.

Compound tubulo-alveolar gland

Structural classification of the breast; composed of branching ducts ending in secretory alveoli.

Glandular tissue (breast)

Milk-secreting epithelial tissue arranged in lobes and lobules.

Connective tissue (breast)

Fibrous stroma that supports lobules and forms suspensory ligaments.

Fat (breast)

Adipose tissue determining most of the breast’s size and contour.

Axillary tail of Spence

Prolongation of breast tissue that passes along the inferolateral edge of pectoralis major toward the axilla.

Areola

Circular pigmented skin surrounding the nipple; lacks fat and hair but contains large sebaceous (Montgomery’s) glands.

Montgomery’s glands

Enlarged areolar sebaceous glands that secrete protective oily sebum for nipple and areolar skin.

Nipple

Cylindrical projection at the areola’s center; lacks fat, hair, sweat glands and contains smooth muscle that erects the nipple.

Suspensory ligament of Cooper

Fibrous bands attaching breast to dermis; support lobules and are best developed superiorly.

Lobe (breast)

One of 15–20 major subdivisions of glandular tissue, each drained by a single lactiferous duct.

Lobule (breast)

Subdivision within a lobe containing 20–40 alveoli that produce milk.

Lactiferous duct

Main excretory duct of each lobe opening independently at the nipple.

Lactiferous sinus (ampulla)

Dilated segment of a lactiferous duct deep to the areola that stores milk droplets.

Retromammary space

Loose connective tissue plane between breast and pectoral fascia allowing breast mobility.

Internal thoracic artery

Medial arterial source to the breast via perforating medial mammary branches.

Axillary artery

Primary lateral arterial supply to the breast through lateral thoracic and thoracoacromial branches.

Posterior intercostal arteries (3rd-5th)

Provide deep posterior blood supply to the breast.

Axillary vein

Main venous drainage route of the breast’s deep venous system.

Internal thoracic vein

Medial venous drainage channel accompanying the internal thoracic artery.

Posterior intercostal veins

Posterior venous drainage of the breast; potential pathway for metastasis to vertebrae.

Superficial venous system (breast)

Network just beneath the superficial fascia that empties into deep veins such as axillary and internal thoracic veins.

Superficial lymphatic drainage (breast)

Lymph vessels draining breast skin (except areola & nipple) mainly to axillary, infraclavicular, inferior deep cervical, and parasternal nodes.

Deep lymphatic drainage (breast)

Lymphatics draining glandular tissue, areola and nipple chiefly to axillary nodes (75%) and other regional nodes.

Axillary lymph nodes

Principal nodes (especially anterior/pectoral group) receiving ~75% of breast lymph.

Parasternal (internal mammary) nodes

Medial chain receiving lymph from medial breast quadrants; may communicate with contralateral breast.

Inferior phrenic lymph nodes

Abdominal nodes receiving lymph from lower breast quadrants, especially medial lower quadrant.

Intercostal nerves (4th–6th)

Provide sensory innervation to breast skin and sympathetic fibers to blood vessels and smooth muscle.

Mammary ridge (milk line)

Longitudinal ectodermal thickening in 4-week embryo extending axilla-to-groin; site of mammary primordia.

Primary mammary bud

Initial epithelial down-growth into dermis in 5th embryonic week.

Secondary mammary buds

Branches of primary bud appearing by 10-12 weeks; later canalize to form lactiferous ducts.

Mammary pit

Superficial depression where lactiferous ducts open before nipple everts postnatally.

Tanner stages

Five clinical stages describing pubertal breast development.

Polymastia

Presence of supernumerary (accessory) breasts along the milk line.

Polythelia

Presence of extra nipples, usually inferior to the normal breast.

Amastia

Complete absence of breast tissue.

Micromastia

Unusually small breasts due to underdevelopment.

Macromastia

Excessively large breasts, often causing physical discomfort.

Athelia

Congenital absence of the nipple.

Microthelia

Abnormally small nipples.