Breast Anatomy• Composed of 15-20 pyramid-shaped lobes.• Separated and supported by Cooper ligaments.• Each lobes contains 20-40 lobules.• Each lobules subdivided into glandular alveoli.• Alveoli composed of secretory acini.• Alveoli empty into lactiferous ducts.• Ducts reach the skin through 9-10 pore in the nipple.• Each lobes and lobules separated and supported by muscle strands and fatty connective tissue.
Breast Anatomy• Supplied by the perforating branches of the internal mammary artery, thoracoacromial artery, internal and lateral thoracic artery and intercostal arteries.• Venous return follows arterial supply, empty into superior vena cava.• Lymphatic drainage through axillary nodes and transpectoral nodes.• Receive sensory innervation from 2nd through 6th intercostal nerves and cervical plexus
Nipple & Areola Anatomy• Nipple is a pigmented, cylindrical structure.• Usually located at the 4th or 5th intercostal space.• On surface, lies multiple openings. One from each lobes.• Areola is the circular pigmented area surrounding the nipple.• Contains a number of Montgomery glands.
Nipple & Areola Anatomy• Nipple and areola contains smooth muscle.• Motor innervation from sympathetic nervous system.
Breast Physiology Stage DevelopmentFetal Breast tissue begins to develop around the sixth week in utero.DevelopmentPrepuberty Ducts are present but nonfunctional – resting state.Puberty Ducts elongate due to estrogen; breast bud appears.Young Adult Progesterone influence initiation of ovulation; ducts elongate; side branches of ducts and lobular elements form.Maturity Lobular elements are well formed.Pregnancy Distal ducts grow and branch; breast enlarge to twice it’s normal weight; increase in mammary blood flow; vascular engorgement and areolar pigmentation.Menopause Lobules begin to recede, leaving mostly ducts, adipose tissue and fibrous tissue.