The mouse vertebrae: changes in the morphology of mouse vertebrae exhibit specific patterns over limited numbers of vertebral levels.

The mouse vertebrae from the cervix to the tip of the tail were characterized and anatomical features that have been lacking were added to the classical description. The vertebrae consist of six long-range and fourteen short-range substructures, with the foveal process being a newly identified substructure. The caudal transverse process, cranial hemal process and hemal ridge are substructures that are clearly defined in the mouse. Each long-range and short-range substructure has several specific morphological features such as length, width, area, shape and angle. These features exibit a crescendo, plateau or decrescendo pattern over a limited number of vertebral segments that ranges from just a few to twenty. The variety of substructural combinations and the constant changes in the morphological features lead to the fact that no single vertebra has the same morphology as any other. An analysis of the patterns of changes in morphology provides some insight into the genetic plan for the metameric body axis.