TY - CHAP M1 - Book, Section TI - The Breast A1 - Wells, Robert G. PY - 2015 T2 - Diagnostic Imaging of Infants and Children AB - Paired ectodermal primitive mammary streaks (milk streaks) form along the ventral surface of the embryo during the fifth week of gestation. These extend from the axilla to the inguinal region. The mammary ridges arise in the thorax from these streaks and there is progressive differentiation into breast parenchyma during fetal development. The other portions of the mammary streaks normally regress; incomplete involution of embryonic breast tissue can result in accessory or ectopic breast tissue anywhere along the primitive mammary streaks. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1148942426 ER -