Elements of the Spine

Vertebrae

The vertebrae support the majority of the weight imposed on the spine. The body of each vertebra is attached to a bony ring that consists of several parts. A bony projection on either side of the vertebral body called the pedicle supports the arch that protects the spinal canal. The laminae are the parts of the vertebrae that form the back of the bony arch that surrounds and covers the spinal canal. There is a transverse process on either side of the arch where some of the muscles of the spinal column attach to the vertebrae. The spinous process is the bony portion of the vertebral body that can be felt as a series of bumps in the center of a person's neck and back.

Intervertebral Disc

The intervertebral discs are located in between each vertebrae and function as shock absorbers and as joints. They are designed to absorb the stresses carried by the spine while allowing the vertebral bodies to move with respect to each other. They made up of a strong outer ring of fibers called the annulus fibrosis, and a soft center called the nucleus pulposus. The outer layer (annulus) helps keep the disc's inner layer intact. The annulus is made up of very strong fibers that connect each vertebra together. The nucleus of the disc has a very high water content making it very moist.

Facet Joint

The facets connect the bony arches of each of the vertebral bodies. There are two facet joints between each pair of vertebrae one on each side. Facet joints connect each vertebra with the next vertebra above and below. They are primarily designed to allow the vertebral bodies to rotate with respect to each other.

Neural Foramen

The neural foramen is the opening where the nerve roots exit the spine and travel to the rest of the body. There are two neural foramen located between each pair of vertebrae, one on each side. The foramen creates a protective passageway for the nerves that carry signals between the spinal cord and the rest of the body.

Spinal Cord and Nerve Roots

The spinal cord extends from the base of the brain to the area between the bottom of your first lumbar vertebra and the top of your second lumbar vertebra. The spinal cord ends by dividing into individual nerves that travel out to your lower body and your legs. This group of nerves at the end of the spinal cord is called the cauda equina, which is the Latin name for a horse's tail. For a short distance the nerve groups travel through the spinal canal before they exit out the neural foramen.

The dura mater is the protective membrane that covers the spinal cord. The dura mater forms a watertight sack around the spinal cord and nerves. The spinal cord is surrounded by spinal fluid inside this sack.

The nerves in each area of the spinal cord connect to specific parts of the body. The nerves of the cervical spine go to the upper chest and arms. The nerves also carry electrical signals back to the brain creating sensations. Damage to the nerves, nerve roots, or spinal cord can lead to symptoms such as pain, tingling, numbness and weakness.

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