Morphological classification of the muscular tubercles of the vertebrae.

Presacral vertebrae, excluding the atlas and axis, obtained from fifty dried vertebral columns were carefully examined to detect the muscular tubercles derived from the attachments of the paravertebral muscles. On the basis of the divisions of these muscles, the tubercles may be classified as follows : (1) tubercles of the median attachments of the back muscles observed at the tips of the spines, (2) tubercles of the lateral attachments of the medial series of the intrinsic back muscles, corresponding to the mamillary processes, observed on the posterior aspect of the cervical articular column and on the upper surfaces of the thoracic transverse processes, (3) tubercles of the lateral series of the intrinsic back muscles and of the posterior laterovertebral muscles, corresponding to the cervical posterior tubercles, observed at the lower surfaces of the thoracic transverse processes, and divided into two in the lumbar region, the accessory processes and the tubercles on the fronts of the costal processes, (4) tubercles of the anterior laterovertebral muscles and of the lateral attachments of the prevertebral muscles, corresponding to the cervical anterior tubercles, observed in the lumbar region at the tips of the costal processes, (5) tubercles of the medial attachments of the prevertebral muscles which exist as small tuberosities of the longus colli on the cervical vertebrae, as tuberculi musculi longi colli (Krmpotic) on the upper thoracic vertebrae and as tuberosities of the psoas major on the lumbar vertebral bodies. Illustrations of typical examples of the above tubercles are provided at the end of the report.