Herniated Nucleus Pulposus eMedicine Orthopedics

Description: The intervertebral disk is the largest avascular structure in the body. It arises from notochordal cells between the cartilaginous endplates, which regress from about 50% of the disk space at birth to about 5% in the adult, with chondrocytes replacing the notochordal cells. Intervertebral disks are located in the spinal column between successive vertebral bodies and are oval in cross-section. The height of the disks increases from the peripheral edges to the center, appearing as a biconcave shape that successively gets larger by about 11% per segment from cephalad to caudal (ie, from the cervical spine to the lumbosacral articulation). A longitudinal ligament attaches to the vertebral bodies and to the intervertebral disks anteriorly and posteriorly; the cartilaginous endplate of each disk attaches to the bony endplate of the vertebral body.
Synonyms and related keywords: herniated disc, HNP, herniated disk, disc herniation, disk herniation, bulging disk, bulging disc, back pain
Author: Mark R Foster, MD, PhD, FACS 2007