There are piercings for nearly every part of the body. However, there are some spots where a traditional piercing just can not be used. That is when dermal piercings are used. Dermal piercings are piercings that go into skin but don’t leave it through the same layer or another layer of skin.
The dermal piercings in the image shown makes one of the most unique sets of piercings I have ever seen and I think it is awesome.