Three-Dimensional Observation of Collagen Framework of Intervertebral Discs in Rats, Dogs and Humans

Abstract

Intervertebral discs of the lumbar spines obtained from rats, dogs and humans are studied by scanning electron microscopy (SEM) and compared with the observations by binocular light and transmission electron microscopy. The three-dimensional architecture of the fibrous components of the discs are examined by SEM in the cut or dissected surfaces of their three distinct parts. 1. The annulus fibrosus is composed of the concentric lamellae of the fibrous bundles, which run uniformly in each lamella and cross over with the bundles of adjoining lamellae. They are made of fine fibrils measuring 0.1-0.2μ in diameter, which probably correspond to the collagen fibrils. 2. The nucleus pulposus is composed of a loose network of fine fibrils forming lamellated membranes at the peripheral part where there is a gradual transition of the membranous network to the lamellae of the annulus. 3. On the inner surfaces of the cartilage plates SEM reveals a close meshwork of fine fibrils after complete removal of the nucleus pulposus. The fibrils in the central areas of the plates are arranged parallel to the surfaces of the vertebral bodies above and below. 4. The three-dimensional architecture of the fibrous components of the discs is discussed from the viewpoint of function as a shock-absorber. © 1973, International Society of Histology and Cytology. All rights reserved.