Multifidus: The Deep Muscle Layer That Controls Spinal Movement

For individuals experiencing lower back pain can understanding the anatomy and function of the multifidus muscle help in injury prevention and in the development of a highly effective treatment plan?

Multifidus Muscle

The multifidus muscles are long and narrow on either side of the spinal column, which helps stabilize the lower region of the spine or lumbar spine. (Maryse Fortin, Luciana Gazzi Macedo 2013) Sitting too much, practicing unhealthy postures, and lack of movement can progress to the multifidus muscle weakening or atrophy, which can lead to spinal instability, vertebral compression, and back pain. (Paul W. Hodges, Lieven Danneels 2019)

Anatomy

Known as the deep layer, it is the innermost layer of the three muscle layers of the back and controls the movement of the spine. The other two layers, known as the intrinsic and superficial, are responsible for the thoracic cage/rib cage and shoulder movement. (Anouk Agten et al., 2020) The multifidus has attachment points at:

• The thoracic spine of the middle back.
• The lumbar spine of the lower back.
• The iliac spine – the base of the wing-shaped iliac bone of the pelvis.
• Sacrum – series of bones at the base of the spine connected to the tailbone.
• When standing or moving, the multifidus muscle works with the transversus abdominus and pelvic floor muscles to stabilize the lumbar spine. (Christine Lynders 2019)

Muscle Function

The main function is to stabilize the lower back, but it also helps extend the lower spine whenever reaching or stretching. (Jennifer Padwal et al., 2020) Because the muscle has numerous attachment points and is serviced by a specific branch of nerves known as the posterior rami, it allows each vertebra to work individually and more efficiently.

• This protects against spinal deterioration and the development of arthritis. (Jeffrey J Hebert et al., 2015)
• The multifidus muscle works with two other deep muscle groups to stabilize and move the spine. (Jeffrey J Hebert et al., 2015)
• The rotatores muscle enables unilateral rotation, turning from side to side, and bilateral extension or bending backward and forward.
• The semispinalis muscle above the multifidus allows extension and rotation of the head, neck, and upper back.
• The multifidus muscle ensures spinal strength because it has more attachment points to the spine than the other layers, which reduces spinal flexibility and rotation but increases strength and stability. (Anouk Agten et al., 2020)

Lower Back Pain

A weak multifidus muscle destabilizes the spine and provides less support to the vertebra. This adds pressure on muscles and connective tissues between and adjacent to the spinal column, increasing the risk of lower back pain symptoms. (Paul W. Hodges, Lieven Danneels 2019) The loss of muscle strength and stability can cause atrophy or wasting away. This can cause compression and other back problems. (Paul W. Hodges et al., 2015) Back problems associated with multifidus muscle deterioration include (Paul W. Hodges, Lieven Danneels 2019)

• Herniated discs – also bulging or slipped discs.
• Nerve entrapment or compression pinched nerve.
• Sciatica
• Referred pain – nerve pain originating from the spine felt in other areas.
• Osteoarthritis – wear-and-tear arthritis
• Spinal osteophytes – bone spurs
• Weak abdominal or pelvic floor muscles can compromise the core, increasing the risk of chronic lower back pain and injury.

Individuals are recommended to consult a physical therapist and chiropractor who can help develop the appropriate treatment, rehabilitation, and strengthening plan based on age, injury, underlying conditions, and physical abilities.

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References

Fortin, M., & Macedo, L. G. (2013). Multifidus and paraspinal muscle group cross-sectional areas of patients with low back pain and control patients: a systematic review with a focus on blinding. Physical therapy, 93(7), 873–888. https://doi.org/10.2522/ptj.20120457

Hodges, P. W., & Danneels, L. (2019). Changes in Structure and Function of the Back Muscles in Low Back Pain: Different Time Points, Observations, and Mechanisms. The Journal of orthopaedic and sports physical therapy, 49(6), 464–476. https://doi.org/10.2519/jospt.2019.8827

Agten, A., Stevens, S., Verbrugghe, J., Eijnde, B. O., Timmermans, A., & Vandenabeele, F. (2020). The lumbar multifidus is characterised by larger type I muscle fibres compared to the erector spinae. Anatomy & cell biology, 53(2), 143–150. https://doi.org/10.5115/acb.20.009

Lynders C. (2019). The Critical Role of Development of the Transversus Abdominis in the Prevention and Treatment of Low Back Pain. HSS journal : the musculoskeletal journal of Hospital for Special Surgery, 15(3), 214–220. https://doi.org/10.1007/s11420-019-09717-8

Padwal, J., Berry, D. B., Hubbard, J. C., Zlomislic, V., Allen, R. T., Garfin, S. R., Ward, S. R., & Shahidi, B. (2020). Regional differences between superficial and deep lumbar multifidus in patients with chronic lumbar spine pathology. BMC musculoskeletal disorders, 21(1), 764. https://doi.org/10.1186/s12891-020-03791-4

Hebert, J. J., Koppenhaver, S. L., Teyhen, D. S., Walker, B. F., & Fritz, J. M. (2015). The evaluation of lumbar multifidus muscle function via palpation: reliability and validity of a new clinical test. The spine journal : official journal of the North American Spine Society, 15(6), 1196–1202. https://doi.org/10.1016/j.spinee.2013.08.056

Hodges, P. W., James, G., Blomster, L., Hall, L., Schmid, A., Shu, C., Little, C., & Melrose, J. (2015). Multifidus Muscle Changes After Back Injury Are Characterized by Structural Remodeling of Muscle, Adipose and Connective Tissue, but Not Muscle Atrophy: Molecular and Morphological Evidence. Spine, 40(14), 1057–1071. https://doi.org/10.1097/BRS.0000000000000972