The spinal column begins at the base of the skull and spans from the cervical spine in the neck through the thoracic spine in the middle back and into the lumbar spine in the lower back. Made up of 24 individual vertebral bodies and several fused vertebrae in the pelvic region, the spinal column is flexible enough to allow for the full range of motion in the neck and back that’s required for daily activity and also strong enough to support the weight of the upper body.
Serving as shock-absorbing cushions for the spine, discs are positioned between adjacent vertebrae to facilitate movement and reduce friction. Each disc has two parts: a thick exterior composed of collagen fiber (annulus fibrosus), which surrounds and contains an inner core of protein gel (nucleus pulposus). These components are high in water content and must remain well hydrated and pliable in order to function properly. For a variety of reasons, the discs can begin to deteriorate and dehydrate over time, becoming brittle and prone to breakage. If a fissure develops in a disc’s annulus fibrosus, some of the nucleus pulposus can pass through its compromised boundary. This condition is referred to as a herniated disc. Pain and other uncomfortable symptoms can develop if displaced inner disc material — which contains inflammatory proteins — irritates or pressures the disc wall, the spinal cord or a nearby nerve root.