A Radiological Consideration of Intervertebral Disc Lesions

Abstract

Towards the end of the second decade of the present century Schmorl discovered the significance of the intervertebral disc. His exhaustive investigations established a firm scientific foundation for our present knowledge. Much credit should be given to Beadle, who, in 1931, submitted a comprehensive report and appreciation of this work. Current literature indicates that the interest aroused has not waned. On the contrary, it exhibits what appears to be an hyperactivity, at least along some paths of enquiry. As an understanding of the normal anatomy and physiology of this structure is a prerequisite to a consideration of its lesions, a summary of the salient features is presented. The intervertebral disc may be considered the joint between the vertebral bodies. These, in association with the posterior intervertebral articulations, form the complex articular system of the vertebral column. The spine and its articular system are particularly liable to stress and strain imposed by an individual's activity. The bone structure being rigid and the mobility of the apophyseal articulations being limited, it follows that the intervertebral disc must possess considerable adaptability. Such proves to be the case. The normal intervertebral disc may be compared to an expansile spring. It is composed of three essential parts: (1) The nucleus pulposus, situated at junction of the middle and posterior thirds, is a firm elastic cushion possessing a strong turgor. (2) The annulus lamellosus provides the form and attachment for the disc. Its concentric fibrous lamellæ are complexly distributed to fulfil this function.