What evidence can you find in the story that the author might have intended to make Jem's broken arm symbolic in To Kill a Mockingbird?
Readers think that Jem's broken arm may symbolize the wound that the system of segregation inflicted on white Southerners.
It is indeed curious that there are two arms disabled--both left arms--in Harper Lee's To Kill a Mockingbird, one white, one black. And, since injustice has been dealt to Tom Robinson, the perpetrator of this injustice, Bob Ewell, is also the agent of the injury inflicted upon the son of the lawyer for justice, Atticus Finch.
It is, perhaps, because this virulent disease, what Atticus has called in Chapter 9 "Maycomb's usual disease," has not been arrested that Bob Ewell feels empowered in his hatred to avenge himself upon the Finch family. For, smug after Atticus's loss in the Robinson trial, Ewell spits in the lawyer's face and boasts of getting even with Atticus Finch. Atticus's "peaceful reaction" prompts Ewell to taunt him, "Too proud to fight, you n--lovin' bastard?" Thus emboldened by Atticus's lack of response, Bob Ewell decides to attack his children, symbolic of the innocent. Thus, his cruel injurying of Jem represents the gratuitous injury to all of society when bias and prejudice reign over reason and fairness, the wound inflicted upon Southern society