MEDICAL ANIMATION TRANSCRIPT: The spine consists of a series of interconnected bones, called vertebrae, extending from the base of the skull to the tailbone. Each vertebrae connects with the one above and below at the facet joints, allowing them to move relative to one another. In between each bony vertebra lies the shock absorbing intervertebral disk. The facet joints and intervertebral disks work together to permit the bending and twisting motions of the back and neck. Protected within the vertebral column is the spinal cord, which connects the brain to the rest of the body. Spinal nerves emanate from the spinal cord at regular intervals. The main sections of the spine are the cervical, thoracic and lumbar regions. Problems that may occur in the lumbar spine include the following conditions, disk degeneration, or spondylosis, a degenerative arthritic condition that may cause loss of normal spinal structure and function, spondylolisthesis, a condition where one vertebra slips forward relative to the one next to it, osteoarthritis of the facet joints, a spinal deformity such as scoliosis, or a fractured vertebra. A doctor may recommend a posterior lumbar spinal fusion to make the spine more stable and decrease pain due to a condition, injury, or abnormal curve. To begin, the surgeon will make an incision over the lumbar spine. The outer surfaces of the bones will be removed to prepare for fusion. The surgeon will place screws into the vertebrae. Rods will be placed alongside the vertebrae and attached to the screws. The surgeon may remove small pieces of bone from the pelvis to use as bone grafts. Other times, the surgeon may choose to use donor bone from a bone bank for grafting. The surgeon will place the bone grafts along the spine to allow the vertebrae a grow together and keep the spine stable. At the end of the procedure, the skin incision will be closed with stitches.