Multiple expanding rib lesions

The turtle shell is a highly complicated shield for the ventral and dorsal parts of turtles, tortoises and terrapins (all classified as "turtles" by zoologists), completely enclosing all the vital organs of the turtle and in some cases even the head. It is constructed of modified bony elements such as the ribs, parts of the pelvis and other bones found in most reptiles. [Source: Wikipedia ]