What is Drop Foot in Multiple Sclerosis?

You’re just going for a simple walk around the neighborhood, something you have done every day for as long as you can remember. All of a sudden you trip. You look around to see what caused you to stumble to find nothing but clean sidewalk. You keep on walking; it happens again! After a few days this keeps happening more and more frequently; you trip over your own foot. Soon you realize that your foot is constantly dragging. You take a step forward but your toes don’t lift up off the ground and instead slide across the floor. This is called drop foot (or foot drop).
What is Going On Here?
There is a muscle on top of the foot called the Extensor Digitorum Brevis muscle which is in charge of lifting the toes upwards (this motion is known as dorsiflex). When you take a step this muscle should activate lifting the toes up and away from the ground but when you’re experiencing drop foot it fails to do this leaving the toes limp. Since they are not being pulled up and away from the ground they drag into it which can cause you to trip. Why is this muscle not activating properly? Well, Multiple Sclerosis attacks the Myelin sheath around your nerves which affects their conductivity. Somewhere along the path that the electrical signal must flow from your brain to your foot to activate that muscle is a lesion preventing the signal from reaching the Digitorum Brevis muscle in charge of lifting your toes. This results in what is called foot drop.
What can be Done to Fix This?

Drop foot is a very common MS symptom so it gets a lot of attention as far as treatment options. Like any other symptom, it should go away in time with or without the use of steroids. If it persists however, there are a few things you can do to make walking easier. Most commonly used is an AFO (Ankle Foot Orthosis) which is a flexible plastic brace that fits under your foot and straps around your lower shin to keep your toes pointed upwards enough to allow you to walk. Most AFO’s are discreet enough that they fit comfortably inside your shoe and remain hidden under your pants.

There are also devices such as the WalkAide available that wrap around your leg (just beneath your knee) and uses electrical stimulation to help activate the muscles in your foot when walking so your foot does not drag. This device contains sensors that help it determine when your taking a step so it knows when to electrically stimulate the peroneal nerve which leads to the muscles in your foot involved in dorsiflexion (lifting your toes).
Physical therapy may also be recommended for gait training.
What Can Happen if You Don’t Treat Drop Foot?

Not treating drop foot can lead to manipulating your gate (the way you walk) so that your foot does not drag. Typically people will lift the leg of the dropping foot higher up than normal. This can cause hip, lower back, and knee pain or possible result in damaging these areas of the body.

4 thoughts on “What is Drop Foot in Multiple Sclerosis?

  • March 19, 2014 at 8:31 pm
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    Very informative Matt. Thank you. Recently diagnosed MSer
    MSer.MSer.
    Regards

    Reply
    • May 21, 2014 at 12:41 am
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      Gait? That is how you walk, a bit different from drop foot. For example, your gait can be "off" because of a him or back problem. Drop foot obviously effects you gait because you can not walk properly with this symptom! :p

      Reply

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