Your spine is a complex structure, made up of 33 individual bones (known as vertebra) stacked one on top of each other. These are supported and connected together by ligaments and muscles, giving them the stability and flexibility it needs to function and move.
The lumbar spine typically has a slight inward curve known as lordosis. The lower back region contains large muscles that support the back and allow for movement in the trunk of the body. These muscles can spasm or become strained, which is a common cause of lower back pain.
The spinal cord, like the brain, has two major layers of protection. First are the vertebrae of the spine, and underneath those are three layers of tough membrane called the meninges. The meninges surround both brain and spinal cord and are filled with a liquid called cerebrospinal fluid.