抄録
The authors presented previously a buckling hypothesis on the etiology of the idiopathic scoliosis by finite element analyses with a finite element model of spine and rib cage. The hypothesis says that the growth of the vertebral bodies induced buckling modes and that the fourth and the sixth buckling modes similar to the clinical modes of the single and the double curves were remained as uncontrollable modes by posture change. This paper investigates a factor of the superior growth of the vertebral bodies in the modeling behavior of the vertebral bodies against the gravity of the head and the trunk. The distribution of the strain energy density under the gravity was concentrated on the front parts of the thoracic vertebrae. The fourth buckling mode induced by the growth in proportion to the strain energy density bore a similar mode to the single curve of clinical idiopathic scoliosis.
