Intervertebral Disc: Definition, Function & Disease

Lesson Transcript
Instructor: Laszlo Vass
Intervertebral discs are pads of fibrocartilage located between the 33 vertebrae in humans and serve a set of functions, including protecting the vertebrae and nerves in the spine. Learn more about the functions of intervertebral discs and explore how they are affected by injuries such as herniated discs and degenerative diseases like arthritis. Updated: 10/14/2021

Intervertebral Discs

The human spine is made out of a series of interconnected bones called vertebrae. You have a total of 33 vertebrae in your spine. These vertebrae are identified by the region of the neck and back in which they are located. Starting from the neck and going down, humans have seven vertebrae in their neck (cervical), 12 vertebrae in the middle of their back (thoracic), five vertebrae in their lower back (lumbar), five vertebrae that are fused together to make the sacrum, and finally four fused vertebrae that make up the coccyx or coccygeal vertebrae (what we refer to as the tail bone).

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  • 0:04 Intervertebral Discs
  • 0:42 Function
  • 1:33 Injuries
  • 2:31 Disease
  • 3:48 Lesson Summary
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Between the individual vertebrae in the cervical, thoracic, and lumbar regions (not in the sacrum and coccyx) are oval shaped pads made of fibrocartilage called intervertebral discs.

The discs have a tough outer covering of cartilage that provides support (the annulus fibrosus) and a soft, jellylike center that provides the cushioning (the nucleus pulposus).

The intervertebral discs have the following functions:

  1. They provide cushioning for the vertebrae and reduce the stress caused by impact. By keeping the vertebrae separated from each other, they act as a type of shock absorber for the spine.
  2. They help protect the nerves that run down the spine and between the vertebrae.
  3. They increase the flexibility of the spine and allow us to bend over at the waist without rubbing the vertebrae into each other.


The intervertebral discs are vulnerable to a variety of injuries. The most common is called a herniated disc (a.k.a., a bulging disc or slipped disc). Herniated discs usually occur later in life. As the discs age, they begin to break down and when a person puts excess stress on them, like lifting something heavy at the waist instead of with the legs, they can rupture, break open, and the jellylike center leaks out. The jelly can irritate surrounding nerves and cause them to become inflamed. This inflammation can put pressure on the nerves, which result in back pain. Herniated discs can be diagnosed several ways, including palpitation (feeling the spine), or x-ray and MRI imaging. Treatment for herniated discs can be as simple as rest and allowing it to heal, taking anti-inflammatory medication to reduce the swelling, and, in some extreme cases, surgery can be performed to repair the damage.

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