To determine the contributions of the various parts of the intervertebral disc to its ability to withstand compressive forces, we did a series of static tests (load versus displacement, creep, and load relaxation) on fresh autopsy specimens. The following preparations were tested: intact disc, disc injected with saline, disc punctured through anular wall, disc with nucleus removed, and anulus alone. About the same compressive stiffness was shown by all specimens (after initial readjustment of height and bulging in some preparations), indicating that the anulus is much more important for the compressive behavior of the disc than has been hitherto believed.