NEW YORK NEUROLOGICAL SOCIETY

Abstract

In an effort to recognize roentgenographically finer changes in the vertebral column in cases of tumors of the spinal cord, a series of measurements of the size of the vertebral canal and a special study of the pedicles were made. As a preliminary, the roentgen films of one hundred normal spines were studied. The following conclusions were reached : The inner borders of the pedicles are convex, but pedicles with flat inner borders occurred in 59 per cent of the films of all parts of the vertebral column, and pedicles with concave inner borders occurred in 20 per cent of the films taken below the level of the seventh thoracic vertebra. The measurements of the distance between the inner borders of the pedicles showed that the distance is greater in the cervical and lumbar regions than in the thoracic region. From the second to the fifth cervical vertebra, the interpedicular spaces increased in size from vertebra to vertebra, while from the fifth cervical to the second thoracic vertebra the space between the inner borders of each pair of pedicles became progressively smaller. It was not unusual, however, for the interpedicular spaces of several vertebrae to be of the same size. From the second to the fifth thoracic vertebra the spaces became gradually smaller. From the fifth to and including the ninth thoracic vertebra the size of the spaces was unchanged. From the tenth thoracic to the fifth lumbar vertebra the spaces become progressively larger, although, just as in the cervical region, it was not unusual for the interpedicular spaces of several vertebrae to be of the same dimension. Exact figures were given regarding the usual and the extreme size of the interpedicular spaces at the different vertebral levels. The studies of the shape of the vertebral pedicles and measurements of the size of the vertebral canal showed that it was possible in a number of instances to make the diagnosis of tumor of the spinal cord and to determine the location and the approximate size of the neoplasm from the roentgen films. It was often possible to confirm clinical signs and to determine exactly where the operation for the removal of a growth should be performed. These studies led to the following conclusions : On anteroposterior roentgen films of the normal spine, the inner borders of the pedicles are usually convex, but pedicles with flat inner borders are frequently seen in all parts of the vertebral column; pedicles with concave inner borders sometimes occur below the level of the seventh thoracic vertebra. Accurate measurements of the interpedicular spaces can be made from the fifth cervical to the fifth lumbar vertebra. The measurements give reliable information as to the comparative size of the canal at the different vertebral levels. In cases of tumor of the spinal cord there is often an increase in the size of the vertebral canal at the level of the growth. This can be recognized by measure¬ ments of the spaces between the pedicles. Enlargement of the canal was found in 43 per cent of sixty-seven cases and was especially frequent when the tumor