<prompt> In patients with breast cancer, chest wall involvement means involvement of any one of the following structures exceptSerratus anteriorPectoralis MajorIntercostal MusclesRibs  <response>: Chest wall involvement means involvement of ribs, intercostal muscles or serratus anterior as chest wall is formed by these structures not the pectoral is major Ref: schwazs principle of surgery 10th edition Pgno :452 