Sagittal Profile of Normal Spine Changes in Spondylolisthesis

Several human postures have been described by anatomists, such as Staffels, Delmas, Bonne and Bellugue [1, 2, 3, 4, 5]. However, these are clinical morphological descriptions, with little or no anatomical foundation. When X-rays became available, the opportunity was offered to standardize the position, to give evidence of this various shapes and to classify them.