A lumbar hernia an uncommon type of abdominal hernia that develops in the lumbar region of the back. The lumbar region is the area of muscles that cover the lower back, from the bottom of the rib cage to the top of the pelvis. Lumbar hernias occur in a area of the back called the lumbar triangle. A lumbar triangle is common on the right-side of the back and can also be present on the left-side. Lumbar hernias develop more often on the right-side because the lumbar triangle is larger on this side of the back. Lumbar hernias can be congenital or the result of injury or trauma to the back or abdomen. In most cases, lumbar hernias are the result of aging, loss of muscle and fatty tissue, and illness that causes immobility or decrease mobility.