What does "WORK ONE’S FINGER TO THE BONE" mean?

What does "WORK ONE’S FINGER TO THE BONE" mean?


                              "Se matar de trabalhar" 

E.g. He´s worked his finger to the bone along five years and now that he asked for a raise, his boss fired him. 
        Ele se matou de trabalhar ao longo de cinco anos e agora que ele pediu um aumento, o chefe o despediu.