What would you conclude about what Atticus plans to reveal when he devotes a great deal of time discussing Mayella Ewell's injuries during the trial?

At the beginning of the trial, Atticus pays particular attention to the location of Mayella's injuries. When Sheriff Tate takes the witness stand, Atticus asks him to describe Mayella's injuries. Tate mentions that Mayella was beaten badly and says that her eye was starting to bruise. Atticus questions which eye Heck is referring to, and Tate initially says that it was her left eye, then recants and says that it was her right eye. Heck Tate confirms that Mayella's right eye was swollen and mentions that the majority of her bruises were to the right side of her face. When Bob Ewell takes the witness stand, Atticus asks him if he agrees with Sheriff Tate's description of Mayella's injuries, and Bob says that he does. Atticus even reads the court reporter's record of Tate's testimony to confirm that Bob agrees that Mayella's injuries were to the right side of her face. Bob says, "I holds with Tate. Her eye was blackened and she was mighty beat up" (Lee 236). Atticus then has Bob write his signature to reveal that he is in fact left-handed.

The reason Atticus spends a great deal of time discussing the location and extent of Mayella's injuries is because he plans to reveal that Tom Robinson could not have been responsible for assaulting Mayella. Atticus knows that Tom's left arm is crippled. A person who throws a punch with their left arm would typically strike the right side of a person's face. If Mayella's injuries are to the right side of her face, it would suggest that an individual who was predominately left-handed beat her. Atticus reveals that Bob Ewell is left-handed, which suggests that Bob was, in fact, Mayella's perpetrator.