Ans: A. Circumferential(Ref Sahiston and Spencer's Surge, of Chest 8/chapter 7)Circumferential incision: generally taken for diaphragmatic surgery.Circumferential incisions:In periphery regions - Result in little loss of function.Must be at least 5 cm lateral to edge of central tendon.To avoid posterolateral & anterolateral branches of phrenic nerve.Difficult to correctly realign after long operation.Placement of surgical clips on each side of muscular incision greatly facilitates correct spatial orientation on closing.