This study was carried out to describe a simple, accurate and practical technique for estimating, the volume of intervertebral disc (ID) by the combination of the Cavalieri principle and computed tomography (CT) images. Total eight lumbar IDs from two cadavers were CT scanned in axial, sagittal and coronal sections, The consecutive sections with 5 and 3 min thickness were used to estimate the volume of the IDs by the Cavalieri principle. Three investigators estimated the volume of IDs independently to evaluate inter-observer differences. When the results were compared to the real volumes of IDs measured by the fluid displacement technique. there was no significant difference between the real Volume measurements and the Cavalieri estimation results of ID volumes (P > 0.05). Moreover, findings of three investigators did not show significant variations (P > 0.05). Our results indicate that the section thickness and the section plane did not affect the accuracy of the disc volume estimation. Thus the combination of CT scanning with the Cavalieri principle may lie used as a direct and reliable technique to estimate the volume of IDs with a mean of 4 min workload per ID. (c) 2004 Elsevier B.V. All rights reserved.