填空題頸胸部瘢痕攣縮畸形切除頸部瘢痕攣縮時(shí),如胸部有較廣泛的瘢痕,則切口應(yīng)向_______延長(zhǎng),直至瘢痕完全切斷松解,同時(shí)在中線胸骨切跡處應(yīng)作適當(dāng)?shù)腳______或_______切開(kāi),或切除一_______瘢痕使胸上部略能張開(kāi)。