Gross Anatomy and Development of the Breast

Vocabulary flashcards summarising key anatomical structures, blood and nerve supply, lymphatics, embryology and clinical anomalies of the breast.

Mammary gland

The functional female breast; a modified sweat gland classified structurally as a compound tubulo-alveolar gland.

Modified sweat gland

Functional classification of the breast, indicating it evolved from skin (sweat) glands.

Compound tubuloalveolar gland

Structural class of the breast, consisting of branched ducts ending in secretory alveoli.

Glandular tissue

Milk-secreting component of the breast embedded in connective tissue and fat.

Suspensory ligament of Cooper

Fibrous bands that attach breast lobules to the dermis and help support the gland.

Axillary tail of Spence

Extension of breast tissue along the inferolateral edge of pectoralis major toward the axilla.

Areola

Circular pigmented skin around the nipple containing large sebaceous (Montgomery’s) glands, but no fat or hair.

Montgomery’s glands

Sebaceous glands in the areola that secrete oily sebum to moisturize and protect the skin.

Nipple

Cylindrical projection at the areola’s centre, lacking fat, hair and sweat glands; contains smooth muscle to erect the nipple.

Lactiferous duct

Single excretory duct from each lobe that opens on the nipple’s surface.

Lactiferous sinus (Ampulla)

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

Lobes (of breast)

15–20 major subdivisions of glandular tissue, each drained by one lactiferous duct.

Lobules

Subunits (≈20–40 per lobe) composed of many alveoli where milk is produced.

Retromammary space

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

Superficial fascia

Layer of anterior thoracic wall in which the breast lies.

Pectoralis major relation

The breast overlies the pectoralis major muscle on the anterior chest wall.

Breast surface boundaries

Extends vertically from 2nd to 6th ribs and horizontally from lateral sternal border to mid-axillary line.

Mammary ridge (milk line)

Ectodermal thickening in week-4 embryo extending axilla → groin; source of mammary glands.

Mammary pit

Initial depression where lactiferous ducts open; mesoderm proliferation after birth everts it into a nipple.

Axillary artery

Major arterial source to the breast via its branches.

Internal thoracic artery

Supplies medial breast through perforating (medial mammary) branches.

Lateral thoracic artery

Branch of axillary artery supplying the lateral breast.

Thoracoacromial artery

Axillary branch contributing to breast blood supply.

Posterior intercostal arteries

3rd–5th branches provide additional breast perfusion.

Axillary vein

Principal vein draining the breast’s deep venous system.

Internal thoracic vein

Receives medial breast venous return.

Posterior intercostal veins

Drain lateral and deep portions of the breast.

Superficial venous system

Veins just beneath superficial fascia that empty into deep veins around the breast.

Superficial lymphatic drainage

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

Deep lymphatic drainage

Lymph from glandular tissue, areola & nipple to axillary nodes (75%) and other deep nodes.

Axillary lymph nodes

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

Parasternal nodes

Internal mammary nodes along sternum draining medial breast quadrants; may cross to opposite breast.

Interpectoral nodes

Lymph nodes between pectoralis major and minor receiving some breast lymph.

Infraclavicular nodes

Nodes below clavicle included in superficial drainage of breast skin.

Supraclavicular nodes

Nodes above clavicle that can receive breast lymph and indicate spread.

Inferior deep cervical nodes

Lower neck nodes draining upper breast skin regions.

Inferior phrenic lymph nodes

Abdominal nodes draining lower medial breast quadrants.

Anterior & lateral cutaneous branches of 4th-6th intercostal nerves

Provide sensory and sympathetic innervation to breast skin, vessels, and nipple smooth muscle.

Sensory fibers

Nerve fibers conveying touch, pain, temperature from breast skin.

Sympathetic fibers

Autonomic fibers controlling blood vessels and smooth muscle in nipple/skin.

Tanner stages

Five clinical stages describing pubertal female breast development.

Polymastia

Presence of supernumerary (extra) breasts along the mammary ridge.

Polythelia

Presence of extra nipples; most common just below normal breast.

Amastia

Congenital absence of breast tissue.

Micromastia

Abnormally small breast development.

Macromastia

Excessively large breast enlargement.

Athelia

Congenital absence of the nipple.

Microthelia

Abnormally small nipple size.