I don’t know anything about this statue other than what you see here. I haven’t been able to find any information on who Anna Spahn that I can definitively state is this particular woman, although the photographs of her monument are popular online. The hairstyle and clothes on this statue make me wonder if this is supposed to represent Anna herself – most cemetery statues aren’t meant to resemble the person buried there, but this one has such distinctive period-appropriate looks, different from the other statues nearby, that it makes me wonder.
A Grave Concern 
“Miss Anna Spahn, 20 years old, 1017 North Franklin street, half sister of State Representative Lawrence C. O’Brien, died Sunday in Henrotin Memorial hospital, where she had been a patient since August. She was graduated from Loyola academy last June. Funeral services will be held Wednesday at St. Joseph’s church, Orleans and Hill streets. Interment in Calvary cemetery”.
Chicago Tribune Nov 21 1922
(I hadn’t recorded her name, but John Martine put me on the right track)