What changes in the skeleton of the lizard appeared why?

Lizards are representatives of the interrupting class.
Changes in the structure of the skeleton associated with life on land:
– the cervical spine consists of a greater number of vertebrae, which makes it possible to turn the head;
– ribs appeared in the thoracic region near the vertebrae, which, together with the sternum, formed a rib cage, due to which the volume of the lungs increases during breathing;
– the lumbar region appeared in the spine, thanks to which the body became more flexible.