摩顶放踵（摩頂放踵）　

◎ 摩顶放踵 módǐng-fàngzhǒng

[dedicate oneself completely to the welfare of mankind;wear oneself out from head to foot to help others] 摩秃了头顶,走破了脚跟。形容不辞辛劳,舍己为人