Sons of Anarchy star Katey Sagal (born Catherine Louise Sagal on January 19, 1954 in Hollywood, California) doesn't have any real scars on her chest, they are part of her makeup for the TV series.
In the series, Gemma Teller Morrow (the character she plays) has had open heart surgery, and the scar is the result of that operation. Gemma has a genetic heart condition from her mother’s side which she passed on to her children.
In the 5th season premiere on September 11, 2012, Gemma talks about her scar to Nero Padilla (played by Jimmy Smits) who has a similar scar also due to heart surgery (which is apparently what got them talking to each other in the first place).
Learn more about Katey Sagal with exclusive news, full bio and filmography as well as photos, videos, and more at TVGuide.com.