Five (or in some cases, six) vertebrae make up the lumbar spine, which provides support for much of the upper body and is rather flexible. The third lumbar spine vertebra (L3) is located in the middle of the lumbar spine, making it particularly susceptible to wear and tear. It is one of the most common sites for causes of chronic lower back pain.
Vertebrae, along with the discs in between them, provide protection for the spinal cord and nerves that run through them. At L1 level, the true spinal cord ends, dividing into nerves called the cauda equina, which run to the lower body and extremities. Age and posture may aggravate common problems with the L3, such as ligament or muscle strain. Less common problems are osteoarthritis or disc hernias. While many symptoms can be alleviated with medication or physiotherapy, surgery or other endoscopic techniques may be an option for chronic back pain.