A simple noninvasive device, “spinal pantograph.” has been developed in order to describe and document the sagittal curves of the spine. The device and the method of evaluating the kyphosis and lordosis are explained. The accuracy of the reproducibility and the comparison with X-ray film findings are discussed. Even the balance of the trunk can be estimated. The sagittal curves in different positions—relaxed standing, maximally erect, and forward bending—can be studied and compared, thus describing the flexibility of the spine. This technique is demonstrated in some cases with different shapes of the sagittal curves of the spine—normal posture and round back deformities, including juvenile kyphosis and structural scoliosis. The effect of flexion braces in juvenile kyphosis and structural scoliosis is discussed.