Does jem brake his arm in To Kill A Mockingbird?

In the last part of the story, Mr. Ewell follows Jem and Scout home when Scout is wearing a Halloween costume. Ewell attacks Jem, but Ewell intends to hurt Scout as payback to Atticus. When Ewell throws Jem about, Jem breaks his arm-- but that is not known until Bo carries Jem to the house and Atticus calls a doctor.