From a roentgenognaphic and anatomical study of 182 lumbar spines obtained at autopsy, the following conclusions were reached:
The distribution of degenerative changes in the lumbar intervertebral joints varies with the lumbar londosis, and the amount of lordosis is not related to sex and age. An increased inclination of the lunibosacral joint seems to protect it against anular damage.
Five basic patterns of radial tears or fissures in the anulus can be identified: posterolateral, posterior bilateral, posterocentral, lateral, and anterior.
The pattern of the tear appears to be related to at least two geometric features of the joint: (1) shape of the disc and (2) symmetry of the articular processes.
In discs with a flattened posterior anular surface posterolateral fissures develop while in discs with rounded posterior surfaces, posterior mid-line ruptures are found.
Asymmetrical anticular processes lead to asymmetrical degeneration, while symmetrical processes lead to symmetrical degeneration.