The Lumbar spine is designed so that the vertebrae stacked together can provide a movable support structure while also protecting the spinal cord from injury. Each vertebra has a strong body in front of the spinal cord to provide a platform suitable for weight bearing, a spinous process - a bony prominence behind the spinal cord which shields the cord's nervous tissue. Cartilage disks are located between the vertebrae, and serve to cushion the spinal column from shock. Each disc features an inner, pulpy center, called the nucleus pulposus, and a fibrous outer ring, called the annulus fibrosus, which is visible in a lateral view of the spine. These intervertebral discs are easily torn or dislocated when the vertebra column is subjected to inordinate stresses, such as those encountered in lifting a heavy load improperly, or twisting the back sharply, as occurs in many sporting injuries.
Ligaments are strong fibrous soft tissues that firmly attach the bones to each other.
Ligaments attach each of the vertebrae and surround each of the discs. Many muscle groups responsible for flexing, extending and rotating the waist, as well as moving the lower extremities, attach to the lumbar spine through tendon insertions. The aorta and blood vessels that transport blood to and from the lower extremities pass in front of the lumbar spine into the abdomen and pelvis. Surrounding these blood vessels are lymph glands and involuntary nervous system tissues which are important in maintaining bladder and bowel control. The uterus and ovaries are important pelvic structures in front of the lumbar area of women.