• Each breast consists of ~15-20 lobes of secretory tissue arranged in radial pattern around nipple.

• Alveoli (hormone sensitive, milk producing microorgans) 

• Lobule is drained by terminal duct and called the TDLU

  • Ducts joint together to drain into a main lactiferous duct and converge at nipple.

• Lobe is embedded in CT & adipose tissue; composed of lobules

• Collecting ducts (~2 mm in diameter) coalesce in subareolar region into lactiferous sinuses (ampullae ~5-8 mm in diameter)

  • 9 - 20 orifices that drain the segments of the nipple.

• Nipple areolar complex: A circular smooth muscle that overlies the 4th intercostal space/slightly lateral to midclavicular line. Smm allows for erection.

  • Projection of nipple is 5 m ahd 5-8 mm in diameter

  • Inversion is when the nipple imaginates into the breast.

  • Retraction is when the nipple is pulled back slightly.

  • Both can be normal if chronic.If they are new, it should make you think about underlying cancers causing distortion.

• Montgomery glands/tubercles: 

  • MG are large intermediate stage sebaceous glands that are embryological transition b/n sweat glands and mammary glands, capable of secreting milk.

  • MG open at the Morgagni tubercles (1-2 mm) raised papules on areola.

  • Complex contains many sensory nerve endings, smm muscle, abundant lymphatic system called the subareolar/Sappey plexus

  • Areola can roughen w MT 

• TDLU: 

  • Extralobular terminal duct

  • Lobule: intralobular terminal duct

  • Ductule / acini

ULTRASOUND

• Fibroglandular tissue: fibrous tissue with fat, ducts, and glands laying on top of the anterior chest wall.

• Axillary extension is called the “tail of Spence”.

• The upper outer quadrant is more densely populated with fibroglandular tissue, which is why most breast cancers start there. 

• There is usually no dense tissue in the medial/inferior breast and retroglandular regions (DANGER ZONES).

NERVOUS SYSTEM

BLOOD SUPPLY

LYMPHATICS