Regarding the length and extent of the human medulla spinalis

Most of our modern text-books on human anatomy state that the spinal medulla is variable in length and in extent within the vertebral canal and that there is no definite relation between the length of the spinal medulla on the one hand and the length of the vertebral column and the height of the individual on the other. It was with these well known facts in mind that the study of this series of 234 cases was undertaken. The observations about to be reported were made on the cadaver in the dissecting room. The material had been prepared for dissecting purposes by the method described by Professor Streeter in volume 5 of The Anatomical Record. During the regular course in Gross Anatomy as given in this department the superficial and deep muscles of the back are identified and removed thereby exposing the entire length of the vertebra1 canal. The neural arches are then removed. The cut pedicles of the vertebrae and the posterior root ganglia of the spinal nerves are exposed. The dural and arachnoid knembranes are opened by an incision along the mid dorsal line bringing into view the spinal medulla and the root filaments of the spinal nerves. The relation of the neural segments of the spinal medulla with the vertebrae is readily determined. Because of the impossibility to determine with accuracy, macroscopically, the lowest point to which the nervous elements of the spinal medulla extend and the beginning of the filum terminale, the attachment of the lowest root filaments of the fourth sacral nerve was taken as the lowest point in all measurements. To avoid error the number of ribs and vertebrae were taken in all cases. The cadaver was placed in the prone position on a