By Jonathan Chu, MD

Interventional Pain Medicine

PM&R

So let’s talk about the multifidus muscle, one of the most important muscles in your low back, and is a muscle that is vital for both stabilizing your spine and preventing low back pain flare ups.

This muscle group is so important, in fact, that many of the most popular physical therapy exercises for low back pain are designed specifically to target the multifidus.

So in this video, I’m going to teach you everything you need to know about this muscle, including a detailed explanation of the anatomy involved, and also talk about ways that you can strengthen the multifidus properly.

So first, let’s take a deep dive into the anatomy of the lower back. This part of the spinal column is known as the lumbar spine. Now, the lumbar spine is composed of 5 vertebrae, which are the largest and strongest in your spine, and they are located below the thoracic spine, which are vertebrae connected to ribs. These lumbar vertebrae anatomically can also be described as sitting on top of your sacrum, which is your tailbone. These lumbar vertebrae and the discs in-between them are quite amazing because they bear the entire load from your upper body and also allow you to bend, twist, extend, and just do all of your activities throughout the day.

Now, it is very important to note next that there are a number of important muscle groups that support your lumbar spine and all the amazing things that it does.

The largest and most superficial muscle group that supports the lumbar spine is known as the erector spinae, which is made up of three muscles that run up and down along your spine, and these three individual muscles are known as the spinalis, longissimus, and iliocostalis. When you just touch your low back, these are the thick bands of muscle that you will feel along both sides of your lumbar spine. If you have a low back pain flare, these are also the muscles that will typically go into painful spasm.

Now, the multifidus muscle is actually deep to the erector spinae, which means that it is located in the layer of muscles beneath the biggest and most powerful low back muscles. The multifidus muscle runs lengthwise along the entire spine, but is the most developed in the lower back. The muscle sits in the groove along the spinous processes, which are the bony prominences that stick out from the back of the vertebral bones, and are the bony prominences that you can palpate when you touch  your lower back.

Now overall, I would say that all the muscles of your low back are very important, and there’s a reason God and nature designed your low back the way it is, and there is a purpose for every muscle and ligament and structure. But the multifidus muscle is especially important, because it is a key stabilizing muscle for the lower back, almost like scaffolding for a tower, and provides both dynamic and static stability, which means that it supports your spine when doing sports and other activities, and also while you’re just sitting or standing. From a common sense standpoint, it is very beneficial for the spine to be properly stabilized and supported, because it protects vital structures like your intervertebral discs, and thus prevents injuries and arthritic degeneration, or at the very least, slows the rate of joint degeneration.

When looking into the medical literature, it has been shown that patients suffering from chronic low back pain often show atrophy, or weakening, of the multifidus muscle, and also show fatty infiltration into this muscle. Furthermore, Cooley and colleagues conducted a study in 2023 that looked at the MRIs of patients being treated for low back pain, specifically at the cross sectional area of the multifidus muscle, and they demonstrated that patients with higher lumbar multifidus quality experienced less low back pain related disability. Another study conducted by Hides and colleagues in 2008 showed that training the multifidus muscle led to a significant decrease in low back pain in young athletes in Australia.

So that being said, if you’re a person who is suffering from low back pain or has just gotten over a low back pain flare, you probably want to know: how do you strengthen this muscle? Well, there are many physical therapy exercises that can target this muscle, but I’m going to give you two that are very popular, simple, and effective.

The first is an exercise called the bird-dog. With this exercise, you get on all fours on an exercise mat, and almost make your back like a table top. Try your best to maintain a neutral spine and engage your abdominal muscles. Then, you will extend your arm and opposite leg, and then hold the position for about 5 seconds before lowering your arm and leg back to the rest position. Then you switch and do the same with the opposite limbs. Now, while doing this exercise you want to make sure to engage your core, keep your hips level, and keep your neck and low back in a straight line; you want to maintain a stable and controlled position and you really don’t want to be flailing all around. You want to repeat this exercise for about 8 to 12 reps, and do between 2 to 3 sets. If you’re someone with a history of low back pain and want to prevent future flare ups, it’s something that I recommend doing 3 times a week at home for maintenance.

Another excellent exercise for the multifidus muscle is the back bridge exercise. For this exercise, you start laying on your back on an exercise mat with your knees bent. Then, you will raise your pelvis up by tightening your low back extensor muscles and glutes, while at the same time also engaging your abdominal muscles also. You want to make your thighs and hips and low back a straight line, almost forming a straight plank from your knees to your shoulders, and then hold this position for 10 to 15 seconds, before going back to the rest position. As you get stronger, you can definitely hold the position longer, for up to 30 to 45 seconds. You can start with 8 to 12 reps and 2 to 3 sets per session, though you can always increase from there as you build up your strength. Maintaining proper form is really the most important, and overall I really have to emphasize quality over quantity, though as you get skilled at the exercise, it’s definitely a positive thing to go up in volume.

Of course, if you’re currently experiencing an acute low back pain flare up and are in too much pain to do any exercises, then you likely need to first “put out the fire” so to speak, and control the pain with an oral medication or an injection, and you can definitely browse this channel to check out other videos where I discuss those options.

So, in conclusion, the multifidus muscle is one of the most important muscles of the low back back when it comes to stabilizing and protecting the spine and preventing low back pain, and hopefully you found this overview helpful and valuable. If you did, feel free to like and subscribe, and also check out the 360 Pain Academy website, which has a lot of free articles and resources, link in the description below. See you in the next video.

References:

Benzon, H. T., et al. (2018). Essentials of pain medicine (4th ed.). Elsevier.

Braddom, R. L. (Ed.). (2010). Physical medicine and rehabilitation (4th ed.). Saunders/Elsevier.

Cooley, J. R., Kjaer, P., Jensen, T. S., Jacques, A., Theroux, J., & Hebert, J. J. (2023). Lumbar multifidus muscle morphology is associated with low back-related pain duration, disability, and leg pain: A cross-sectional study in secondary care. PLOS ONE, 18(6), e0285993.

Cooley, J. R., Jensen, T. S., Kjaer, P., Jacques, A., Theroux, J., & Hebert, J. J. (2024). Spinal degeneration and lumbar multifidus muscle quality may independently affect clinical outcomes in patients conservatively managed for low back or leg pain. Scientific Reports, 14, Article 9777.

Cuccurullo, S. J. (2004). Physical medicine and rehabilitation board review. Demos Medical Publishing.

Hides, J. A., Stanton, W. R., McMahon, S., Sims, K., & Richardson, C. A. (2008). Effect of stabilization training on multifidus muscle cross-sectional area among young elite cricketers with low back pain. Journal of Orthopaedic & Sports Physical Therapy, 38(3), 101–108.

Liebenson, C. (Ed.). (2007). Rehabilitation of the spine: A practitioner's manual (2nd ed.). Lippincott Williams & Wilkins.