A type of surgery used to rebuild the shape of the breast after a mastectomy. A muscle in the back called the latissimus dorsi, along with skin, fat, and blood vessels, is moved from the back to the chest to form a new breast mound or to form a pocket for a breast implant. This is usually done by passing the muscle tissue and blood vessels through a tunnel under the skin to the chest. A latissimus dorsi flap is a type of breast reconstruction.