Artículo
The following figure shows in A, is a bridge right Sulcata and B the left, you can see the big differences shields in A the bridge has not grown at the same pace as in B, with consequent deformations.
Reading the article recommended
Lesiones ulcerativas cutáneas en tortugas dulceacuícolas, (cutaneous ulcerative lesions in freshwater turtles) de J. L. Granados, O. G. Moreno2, C. I. Brieva
http://www.revistas.unal.edu.co/index.php/remevez/article/view/37893/40143