Fluoroscopy is a common imaging technique in spinal medical technology. Fluoroscopic imaging works by utilizing X-Rays to get images of the spine so as to provide doctors, engineers, and scientists to get a better view of bones and tissue.

This fixture must not inhibit fluoroscopic imaging, and hence the X-Ray images, so as to provide a clear image and understanding of the mechanisms and workings of an implant when inserted into the spine.

The human spine has six degrees of freedom which allows for its natural motion, including in the x, y, and z direction. This mechanism allows for a wide range of motions to occur in the spine, which are listed below:

• Lateral -  Bending side to side

• Rotation - Twisting the spine

• Flexion - Bending forwards

• Extension - Bending backwards

This fixture must allow for the spine to function within its six degrees of freedom so as to prevent any unnatural motion inhibition to the spine.

In terms of biomechanics, coupled motion is the idea that when motion is introduced into one axis of a subject, there is a secondary motion that occurs in a separate axis.

In terms of the spine, coupled motion is a relationship that exists between different vertebrae when a motion such as rotation or bending is introduced.

This fixture must allow for the coupled movement of the spine to make the spinal segment behavior more representative of the workings of an actual human spine.