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A twitching calf muscle may seem like no big deal, and if it’s just a temporary annoyance that lasts a couple of days and then goes away, it may be. However, it can also be a warning sign of something bigger, especially if it continues. So today we’re going to explain a little about the calf and why it’s not a good idea to ignore calf muscle twitching.

What Is the Calf Muscle?

If there’s one muscle you’re likely familiar with, it’s the calf muscle. If you reach around and grab your calf and flex it, the muscle you are actually feeling just under the surface is called the gastrocnemius muscle in medical terminology. The top of the muscle attaches behind the knee, and the bottom connects to the Achilles tendon, which stretches all the way down to the heel. If you’re a runner or even just exercise regularly, you probably spend time stretching the calf muscle—one, because it feels really good, and two, because it helps protect the muscle from damage. And who hasn’t woken up in the middle of the night at least once with the dreaded calf muscle cramp?

What Causes Calf Muscle Twitching?

The calf muscle, like every muscle, has an innervation. This means it has a nerve that supplies the muscle and tells it what to do. The nerve branch for the calf muscle starts all the way up in the lower spine. If the nerve is injured or just becomes irritated, this can cause the calf muscle to involuntarily twitch (fasciculate is the medical terminology), a reflex response when the muscle isn’t being supplied with instructions from the nerve on what it’s supposed to do.

So what can injure the nerves in the calf muscle? Several nerves innervate the calf muscle. For example the S1 (sacrum level 1) nerve in the low back becomes the tibial nerve in the leg, which then innervates the calf muscle. If there is a bulging or herniated disc, for example, at the S1 level, this can put pressure on the nerve, and this nerve irritation can present as a twitching muscle in the calf. Likewise, an injured tibial nerve can also present as a twitching calf muscle.

Let’s Take a Look at an Actual Twitching Calf Muscle

Calf muscle twitching can be so subtle, you may not even realize it’s happening, or it can be dramatic and even create some pressure in the calf, or it can be anywhere in between. Watch Dr. Centeno’s very brief video of a patient’s calf muscle as it twitches dramatically as well as an ultrasound image as the twitching occurs compared to a muscle that isn’t twitching.

To Stop the Twitching Caused by Nerve Irritation, Treat the Nerve

The most common cause of a twitching calf muscle in S1 nerve irritation in the back. Typically, this nerve irritation occurs due to a disc issue or inflammation from arthritis putting pressure on the S1 nerve. So to stop the twitching caused by an irritated S1 nerve, the nerve must be treated. In interventional orthopedics, we can treat this issue with a platelet lysate epidural. This involves using precise image guidance to inject growth factors from the patient’s blood platelets around the irritated or injured nerve. In addition, if there is a bigger disc bulge, if the disc degeneration isn’t too advanced, this can be treated with an injection of specially cultured stem cells.

While it might be OK to shrug off a calf muscle twitch that happens once or twice and doesn’t return, it’s never a good idea to ignore calf muscle twitching that continues. It’s a big red warning flag that the nerves aren’t functioning as they should. And, as always, it’s best to treat a problem when the warning signs occur rather than waiting it out and trying to treat it once a problem has advanced to something bigger and more difficult to manage.