As with other parts of the human body, intervertebral discs are subject to the adverse effects of aging, normal daily activity, and injury. As adults age, the nucleus propulsus (NP) gradually contains less water and proteoglycans, and the outer annulus fibrosus (AF) acquires small localized fissures and tears. Such degenerative processes in intervertebral discs progress over time and are irreversible, and compromise the structural integrity and mechanical function of the spine. Patients with disc degeneration or injury may present with decreased spinal flexibility, stability, and load bearing capacity, as well as pain that waxes and wanes or is chronic. The current gold standard for assessment of disc degeneration is a subjective ranking system, based on gross morphological features. Edward Vresilovic, M.D., Ph.D., and his colleagues at Penn State Hershey Bone and Joint Institute, however, are working to change this by developing a quantitative, biomechanical approach toward disc degeneration investigation, diagnosis, and treatment. Vresilovic explains, “The function of intervertebral discs is largely mechanical, and it should be possible to use objective measures to quantify changes in the internal stress-strain environment of discs during physiologic loading.” Until now the inner workings of the intact disc under load have not been adequately characterized due to difficulties in measurement without invasively altering the disc.