SPINE SCIENCE

The spinal column is made up of bones (vertebra), discs (intervertebral discs), and soft tissues (muscles, tendons and ligaments). The spinal cord runs from the base of the skull to the pelvis through a channel at the back of the spinal column.

It carries electrical signals from the brain to the muscles, and signals from sensory receptors in the body to the brain. The spinal cord terminates between the first and second lumbar vertebrae (L1/2) which lies just below the rib cage. A bundle of individual nerves (cauda equina) courses downwards supplying the body below this level.

BONES


The neck (cervical spine) is composed of 7 bones, chest (thoracic spine) of 12 bones, and the low back (lumbar spine) of 5 bones.

Small nerves (“nerve roots”) enter and exit from the spinal cord through spaces between the vertebrae.

Intervertebral Disc

The intervertebral discs lie between the vertebrae. These are composed of round, spongy pads of cartilage called intervertebral discs that allow for flexibility in the lower back and act much like shock absorbers throughout the spinal column to cushion the bones as the body moves.

The outer part of the disc is composed of a fibrous envelope (annulus fibrosis). This is composed of multiple layers of specialised protein fibres (collagen).The inner part of the disc is composed of a complex protein gel (proteoaminoglycan) which absorbs water. As we age the proteins within the disc degenerate, losing their ability to retain water and the disc gradually deflates.

Bands of tissue, known as ligaments and tendons hold the vertebrae in place and attach the muscles to the spinal column.

SPINAL DEGENERATION

Degeneration of the intervertebral discs first becomes apparent from the late 20s onwards.

Disc degeneration is dependent on multiple factors, including the individual patient’s genetic makeup, lifestyle and injuries to the disc that may have occurred.

By mid to late thirties most people will have evidence on MRI scanning of disc degeneration.