Lumbar vertebrae

Lumbar vertebrae , vertebrae lumbales, number 5, differ from others by their massiveness. The body is bean-shaped, the arches are highly developed, the vertebral foramen is larger than in the thoracic vertebrae, and is irregularly triangular in shape.

Each transverse process, located in front of the joint, is elongated, compressed from front to back, goes laterally and somewhat posteriorly. Its most part - the costal processus costalis, - represents the rudiment of the rib . On the back surface of the base of the costal process there is a weakly pronounced additional process, processus accessorius, - the rudiment of the transverse process.
The spinous process is short and wide, thickened and rounded at the end. The articular processes, starting from the arc, are directed posteriorly from the transverse and are located almost vertically. The articular surfaces lie in the sagittal plane, with the upper concave and facing medially, and the lower convex and directed laterally.
When articulating two adjacent vertebrae, the upper articular processes of one vertebra cover the lower articular processes of the other. In the posterolateral margin of the superior articular process there is a small mastoid processus, processus mamillaris, the track of the attachment of muscles.

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