The novel tells us the events leading up to Jem breaking his arm. Why is it important that he is still affected by that injury?

Jem's broken arm is a result of Bob Ewell's attack on the children the night of the pageant. Jem's broken arm becomes a symbol of many of the themes in the story. Courage, broken society, and an attack on innocence are just a few of these themes. Jem is shaped by all of these themes.