Three-dimensional architecture of lumbar intervertebral discs.

Three-dimensional observations of the collagen framework of lumbar intervertebral discs by scanning electron microscopy confirmed that the fibrillar framework of the annulus and the cartilage end-plate was made of nucleus as a closed pack system. The cartilage end-plate was made of dense collagen framework aligned horizontally. There was no interconnection between the cartilage end-plate and the lamellar subchondral collagen. In places, the vascular channels ran directly at the end-plate. In the inner one third of the annulus, obliquely oriented fibrillar lamellae interconnected with the cartilage end-plate. In the outer two thirds, the fibrillar lamellae were formed from fibrillar bundles and were firmly anchored into the vertebral bodies. Architectural relationships between the disc and the vertebral bodies are discussed.