Since a free flap is a muscle or soft tissue flap that has its blood supply divided and re-attached somewhere else in the body, there needs to be an artery and vein that can connect to (anastomosed) in the chest. Often the vessels are found toward the sternum. The vessels commonly used are the internal mammary artery and vein on the same side as the breast defect. A small piece of rib is sometimes removed to gain access to these vessels. Occasionally, branches of the axillary artery found in the armpit might be used for the anastomosis.