Structure and function of the lumbar intervertebral disk in health, aging, and pathologic conditions.

This report is a comprehensive review of the basic and clinical science relating to the morphology and function of the intervertebral disc of the lumbar spine. The purpose is to review the anatomy, physiology, and biomechanics of the intervertebral disc of the lumbar spine in health, with aging, and in pathologic conditions. The complex morphology and ultrastructure of the intervertebral disc of the lumbar spine in the human provide the critical elements that permit normal mobility and transmission of force through the vertebral column. Alterations in this structure are manifest in a variety of clinical conditions routinely encountered in orthopaedic physical therapy practice. These structural and biomechanical changes are related to degenerative changes that occur in association with aging and trauma. Knowledge of the gross morphology and ultrastructure of the intervertebral disc and pathobiologic processes underlying associated conditions is essential to orthopaedic practice.