The joints of the vertebral column include the joints of the vertebral bodies, the joints of the vertebral arches, the craniovertebral joints, costovertebral joints, and the sacroiliac joints.

These joints bear the body weight when sitting or standing, and give us the flexibility to do the downward dog in yoga class.

Let’s start with the joints of the vertebral bodies, which are symphyses or secondary cartilaginous joints - that aid in weight-bearing and provide strength to the vertebral column.

The articulating surfaces of adjacent vertebral bodies attach to each other by fibrocartilaginous discs called intervertebral discs or IV discs for short, in addition to numerous ligaments.

The intervertebral discs function as shock absorbers between adjacent vertebrae.

They also allow for limited movement between adjacent vertebrae, and while the movement between any two vertebrae is minor, the summation of those limited movements throughout the entirety of the vertebral column allow for the large movements of our spine.

The intervertebral discs consist of two distinct parts, a thick, tough, fibrous outer ring called the anulus fibrosus and a soft gelatinous core called the nucleus pulposus which the anulus fibrosus surrounds.

The anulus fibrosus is made up of circular layers of fibrocartilage, which allows the discs to withstand compression.

Now, the nucleus pulposus provides both flexibility and resilience to the intervertebral discs, where the gelatinous core allows the discs to absorb shock when they’re compressed by vertical forces.

The nucleus pulposus is avascular, receiving blood via diffusion from vessels at the periphery of the anulus fibrosus and vertebral body.

Now, intervertebral discs are named based on the two vertebrae they lie between.

For example, the C2-C3 disc is the disc between the C2 and C3 vertebral bodies.

There are 23 intervertebral discs, starting from the C2-C3 disc all the way down to the L5-S1 disc.

In case you’re wondering, the reason why there’s no disc between C1 and C2 is that these two vertebrae form a different type of joint, called the atlanto-axial joint.