[Lumbar intervertebral disk. Structure. Knowledge status].

The purpose of this paper is to review the main data on the structure of the intervertebral disc, which are illustrated by personal documents. Applications in understanding the degenerative pathology are highlighted. The nucleus pulposus is the "central" component of the disc, highly hydrophilic, deformable but remaining of constant volume. It can be compared to a hydraulic chamber within the disc, sealed by the annulus fibrosus, which is a dense peripheric ring of concentric fibrous lamellae. The cartilaginous end plates (cranial and caudal) separate the disc from the adjacent subchondral vertebral bone. (Their involvement in the discal metabolism as well as the blood supply of the disc are developed elsewhere (see our companion article)).