Lumbar Vertebrae (Anterior View)

[Continued from above] . . . (L1 through L5) are the largest of the movable or true vertebrae, with substantial ventral bodies or centrums that are more wide than deep. Their articulating bodies are especially large and rather kidney-shaped with slightly concave faces above and below, plus a more deeply concave curve in the back. Intervertebral discs made of cartilaginous connective tissue cushion the joints above and below to protect and support the spinal column. The spinal cord moves from the bottom of the skull, through the cervical and thoracic vertebrae to end around T12-L1. Here the cord splits into a bunch of nerve roots called the cauda equine, which extend to the lower portions of the body. The vertebral arch includes strong, short, and wide laminae; substantial pedicles; long, thin transverse processes; and a fairly rectangular spinous process that extends almost horizontally from the body of the L1-L5 vertebrae.

The lumbar vertebrae lack the transverse foramina in the transverse processes, and also lack facets to either side of the centrum. The fifth lumbar vertebra is distinct from the L1-4 vertebrae in being much larger on its front side than in the back. Its spinous process, on the other hand, is smaller than in the other lumbar vertebrae with a wide, four-sided shape that comes to a rough edge and a thick notch.