摘要: The embryology of the breast shows that ectoderm and mesenchyme are responsible for genesis male female breast, with formation ducts alveoli connective tissue its vessels. milk ridge develops in ventral area body, pectoral part produces right left mammary. Very little is known about molecular mechanisms initiate formation. chronology development discussed through developmental differentiation phases. Developmental anomalies can occur, such as bilateral amastia, unilateral amastia congenital ectodermal defects, athelia, polythelia, polymastia, asymmetry. anatomy described.