The risen Christ showing his wounds. It was a popular topic in medieval art.
The scene is not described in the New Testament. But there is a passage in Isaiah 53:3-4 that mentions a despised and rejected man carrying our griefs and sorrows.
Several variants are known in art, ranging from just the head with the crown of thornes to the full length tortured body. Usually the instruments of the Passion are present.
Related works of art: