Spine Anatomy - Part 2 Intervertebral Discs

Spine Anatomy Part 2: The Disc

There are a total of 23 vertebrae in the spine and thus 23 discs located in between each vertebrae. The discs are soft tissue which helps to cushion between the vertebral bones inside the spinal column. They are made mostly of water, proteins and collagen. The disc function to facilitate movement, provide shock absorption, and help to create the spinal curves. The spinal curves along with the discs help to distribute the weight and force throughout the body. Discs are attached to the vertebrae above and below by cartilaginous end plates and they receive all their nutritional requirements through these cartilaginous end plates. They have any blood vessel attachments.

Disc specific anatomy:

The disc is named for its shape and function. It is a round shape, like a disc, and is made of the outer wall and the inner nucleus. The outer wall of the disc is called the annulus fibrosis. The design of this outer wall is made up of alternating direction layers of cells that are very strong and helps the disc to resist the huge loads and forces placed on it by all of our spinal movements. The inner section of the disc is called the nucleus pulposus. It has a soft jelly-like core that is saturated with moisture and is very flexible. The inner core of the disc is constantly hydrating and dehydrating as part of its normal day to day activity. As we age, the nucleus loses its ability to effectively hold moisture, thereby shrinking in mass, height and circumference. This harmless and expected process is called disc degeneration, also known as degenerative disc disease.

Spine Anatomry Part 3: Muscles of the Back