Anna Linstrom was a Swedish nurse who made a one time appearance in the Season 2 episode of M*A*S*H titled "Dear Dad...Three". The part of Anna is played in the episode by Sivi Aberg.
About Anna Lindstrom[]
During the happy hour at the end of the episode, Trapper brings a girl into the mess tent and introduces her to Hawkeye as "Nurse Anna Linstrom" from the Swedish unit. Hawkeye invites Anna to sit with him while he finishes his letter to his father. He sings a few lines from "Makin' Whoopie" while writing, which leads Anna to ask what "Whoopie" means. Hawkeye slyly replies, "I'll be with you in a minute, darling."
The only Swedish unit in Korean at that time was the Swedish Red Cross Field Hospital so it can be deduced that Anna must belong to the Red Cross, although she is wearing US pattern military fatigues. Her rank is never stated, but something shiny can be seen on her right lapel, so she is probably an officer, most likely a lieutenant, which is a common entry-level rank for nurses in many uniformed services.