What Is The Zygapophysis?

The vertebral column that houses the spinal cord is made up of many vertebrae which are grouped based on their location. The vertebral groups are divided (in a descending order) into seven cervical vertebrae (neck area), twelve thoracic vertebrae (upper back), five lumbar vertebrae (lower back), sacrum (lower pelvis), and coccyx (terminal end of spine). From the observations of the cervical, thoracic, and lumbar vertebrae, it was found that they all share the same unit structure. They all possessed the same structures- neural spine, neural arch, centrum, zygapophysis, and a centrum. It was found that the size of these structures increased as you move down the vertebral column, with the cervical vertebrae being the smallest. Moreover, it was
For the purposes of this experiment, anatomical planes were used to better visualize the movements of the spine. The planes involved are the saggital plane and transverse plane. The movements that the subjects were asked to perform can be divided into two groups based on the planes that the spine acts on. The flexion and extension of the spine involves movement in the saggital plane, while the rotation and bending of the spine (left and right) involves movement in the transverse plane. An outcome that will support the hypothesis is if the zygapophyses in the thoracic region was found to have more of an angular displacement than in the lumbar region for at least two of the three motions described above. This would suggest that the extra space between the zygapophyses in the thoracic region would allow for a more range of movement than in the lumbar region. On the other hand, an outcome that would refute the hypothesis is if the zygapophyses in the lumbar region was found to have more of an angular displacement than in the thoracic region for at least two of the three motions described above. Another outcome that would refute the hypothesis is if zygapophyses in both the thoracic and lumbar region were found to have equal angular displacements for the the three motions. These two outcomes would suggest that the extra space between the zygapophyses in the thoracic region does not provide any extra degree of movement. While this experiment can support the hypothesis, it does have its limitations. X-ray images of the spine are sometimes difficult to read and a small structure such as the zygapophysis is no exception. Therefore, measuring the angular displacements of the zygapophyses would include some uncertainties in the measurements.