Herniated Disc (Part 1): Anatomy of a Disc

Being an educated health consumer will help you make informed choices along a treatment road that may take a number of twists and turns. The goal is to achieve healing of the injured disc with as few risks and side effects as possible, and to return to your normal, active life free of pain.

In this series, I will be presenting you with facts about bulging, herniated and ruptured discs, what research tell us about how the disc functions and how the disc is injured, alternative treatment approaches including surgery, and my approach to treating discs based on my clinical experience as a portland chiropractic disc specialist.


Discs are called “intervertebral discs” because they sit between each vertebra (or spinal bone) to act as shock absorbers and transmitters. Just think how many ways we can move our spine and how many activities we engage in that involve rapid, changing motions of the neck and back.

All this is taking place in a field of gravity that our body has to work against in order to maintain an erect posture. It is the construction of our spine with its separate vertebra and the flexibility and resiliency of our discs that allows us to engage in the full range of human activities.

The spine can be characterized as a series of joints, or units of motion. A spinal unit of motion consists of two bony vertebrae, the disc in-between the bones, the ligaments stabilizing the joint, and related muscles, blood vessels and nerves.

The disc is made up of a gelatinous central portion called the nucleus pulposus and concentric rings of fibrous material called the annulus fibrosis.

The arrangement of the annular layers allows the disc to resist forces or loads placed on the spine. The annulus is divided into inner fibers which are attached to a plate of cartilage attached to the body of the vertebra and outer fibers, called Sharpy fibers, which as attached directly to the vertebra.

It is important to note that studies indicate that the outer annular fibers are innervated, or have nervous supply, and the inner fibers and the nucleus pulposus are not innervated.

Two important ligaments add stability to the disc: the anterior longitudinal ligament (ALL) in front and the posterior longitudinal ligament (PLL) in the back. Both ligaments are innervated. Interestingly, research indicates that degenerated human discs contain more nerve tissue and are more vascular than normal discs.

Next: Herniated Disc (Part 2): Function of the Disc

( Dr. Arn Strasser is a chiropractor who practices in portland, oregon. For more information and appointment questions, call 503.287.2800)

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