The mammillary is connected in the lumbar region with the back part of the superior articular process.

The pars interarticularis, or pars for short, is the part of vertebra located between the inferior and superior articular processes of the facet joint.

This fracture represents a fracture through the posterior elements including the superior articular processes but not the spinous process, as well as an avulsion fracture of the vertebral body.

The superior articular processes project from it on either side; they are oval, concave, directed backward and medialward, like the superior articular processes of a lumbar vertebra.

A zygapophysial joint (zygapophyseal, apophyseal, Z-joint, or facet joint) is a synovial joint between the superior articular process of one vertebra and the inferior articular process of the vertebra directly above it.

The superior articular processes are thin plates of bone projecting upward from the junctions of the pedicles and laminae; their articular facets are practically flat, and are directed backward and a little lateralward and upward.

Of the three tubercles noticed in connection with the transverse processes of the lumbar vertebrae, the superior one is connected in the lumbar region with the back part of the superior articular process, and is named the mammillary process (processus mamillaris) or mammillary tubercle.

The transverse processes arise from the arch behind the superior articular processes and pedicles; they are thick, strong, and of considerable length, directed obliquely backward and lateralward, and each ends in a clubbed extremity, on the front of which is a small, concave surface, for articulation with the tubercle of a rib.