The breast won't have muscles. Breast tissue is found in addition to the muscles on the upper body wall. Blood vessels and lymphatic vessels (a program of vessels that drains fluid) can be found through the entire breast. Breast tissue starts to type in the fourth 7 days of fetal https://grok.com/share/c2hhcmQtMw%3D%3D_21b4ddf4-c274-418a-a078-c9d2af4898ff