Functional Spinal Unit

This article is a stub.

The functional spinal unit.^[1]

The functional spinal unit (FSU) is the smallest motion segment of the spine. It includes two vertebrae with an interleaving intervertebral disc anteriorly and two facet joints posteriorly. In the normal state, approximately 70% of axial compression is transmitted by the vertebral bodies and discs and the remaining 30% posteriorly through the facet joints.

Components

a. Vertebral Bodies: The vertebral bodies are cylindrical-shaped structures that form the anterior part of the FSU. They are responsible for bearing the majority of the axial load and providing structural support to the spine.

b. Intervertebral Discs: These are fibrocartilaginous structures located between the vertebral bodies, acting as shock absorbers and load distributors. They consist of an outer annulus fibrosus, which surrounds the inner nucleus pulposus. The intervertebral disc's primary functions include providing flexibility, maintaining spinal height, and absorbing compressive forces.

c. Facet Joints: Also known as zygapophyseal joints, facet joints are paired synovial joints located posteriorly in the FSU. They provide stability and guide spinal motion by limiting excessive movement in different planes.

Resources

ABCs of the degenerative spine - 6.72 MB (f)

References

↑ Kushchayev, Sergiy V.; Glushko, Tetiana; Jarraya, Mohamed; Schuleri, Karl H.; Preul, Mark C.; Brooks, Michael L.; Teytelboym, Oleg M. (2018-04). "ABCs of the degenerative spine". Insights into Imaging. 9 (2): 253–274. doi:10.1007/s13244-017-0584-z. ISSN 1869-4101. PMC 5893484. PMID 29569215. Check date values in: |date= (help)

[1] Kushchayev, Sergiy V.; Glushko, Tetiana; Jarraya, Mohamed; Schuleri, Karl H.; Preul, Mark C.; Brooks, Michael L.; Teytelboym, Oleg M. (2018-04). "ABCs of the degenerative spine". Insights into Imaging. 9 (2): 253–274. doi:10.1007/s13244-017-0584-z. ISSN 1869-4101. PMC 5893484. PMID 29569215. Check date values in: |date= (help)

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