SS blood group tattoos (German: Blutgruppentätowierung) were worn by members of the Waffen-SS in Nazi Germany during World War II to identify the individual's blood type. After the war, the tattoo was taken to be prima facie, if not perfect, evidence of being part of the Waffen-SS, leading to potential arrest and prosecution. This led a number of Ex-Waffen-SS to shoot themselves through the arm with a gun, removing the tattoo and leaving scars like the ones resulting from pox inoculation, making the removal less obvious.
Tattoo sleeves are defined as a large tattoo or a bunch of small random designs that when placed together cover most of the arm. A serious and committing tattoo style, sleeves start at the shoulder and continue down, usually carrying a centralized theme. While sleeve tattoos continue to rise in popularity, especially among women, you should always consider the following before opting for a full arm of art.
The American Academy of Dermatology distinguishes five types of tattoos: traumatic tattoos, also called "natural tattoos", that result from injuries, especially asphalt from road injuries or pencil lead; amateur tattoos; professional tattoos, both via traditional methods and modern tattoo machines; cosmetic tattoos, also known as "permanent makeup"; and medical tattoos.