Transverse process

The transverse processes, two in number, project one at either side from the point where the lamina joins the pedicle, between the superior and inferior articular processes. They serve for the attachment of muscles and ligaments.

The transverse process of a lumbar vertebra is also called costal or costiform process, because it corresponds to a rudimentary rib (costa) which, as opposed to the thorax, is not developed in the lumbar region.

The opinion of FIPAT in TA2 is that the Processus transversus of cervical and lumbar vertebrae is composed of a costal element (Pars costalis) and a transverse element (Pars lateralis or "true" transverse process).