As a result of study of the anatomy, embryology, and physiology of the intervertebral disc, the following conclusions are drawn:
1. Vascular channels in the cartilaginous plate are normally present only in the first three decades of life.
2. There is no central "joint cavity" in the intervertebral disc.
3. No mucus was demonstrated in the intervertebral disc by De Galantha's stain.
4. The peripheral bony ring, epiphysis, or Randeiste is present as a complete ring, and is not absent posteriorly.