The breast doesn't consist of muscles. Breast tissue is found on top of the muscles on the upper body wall. Blood vessels and lymphatic vessels (a system of vessels that drains fluid) can be found all over the breast. These implants are created of the thicker, far more cohesive silicone https://grok.com/share/c2hhcmQtMw%3D%3D_21b4ddf4-c274-418a-a078-c9d2af4898ff