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The front of the foot will not lift, so the toes catch on the ground and the leg swings wider to clear them. Foot drop is a sign of something interrupting a nerve — the question is where.
The same dropped foot can come from four quite different places along the path from brain to ankle. What separates them is rarely the foot itself — it is what else is going on, and how the trouble began.
| At the knee peroneal nerve | At the spine L5 nerve root | Nerve disease neuropathy | Brain or cord | |
|---|---|---|---|---|
| One foot or both | One | One | Usually both | One side of the body |
| How it began | After kneeling, squatting, crossing the legs, a cast or an operation | Over days or weeks, often with back pain first | Over months or years | Suddenly |
| Back or leg pain | Usually none | Often sciatica down the leg | Burning in both feet | Varies |
| Where it feels numb | Outer shin and top of the foot | Outer shin, top of the foot, often into the big toe | Both feet, like socks | Whole leg or one whole side |
| Anything else weak | No — only lifting the foot and turning it out | Sometimes the hip or the big toe | Grip and balance in time | Arm, face or speech |
| Tender at the outer knee | Often, with tingling when tapped | No | No | No |
Foot drop that arrives suddenly alongside weakness in the arm, drooping of the face or difficulty speaking is a different situation altogether. That combination needs emergency assessment the same hour, not a clinic appointment. So does a dropped foot with numbness around the back passage or loss of bladder control, which points to pressure on the lowest spinal nerves.
Lifting the foot is the job of a small group of muscles on the front of the shin, and they answer to one nerve. That nerve leaves the spine at the L5 level, travels down as part of the sciatic nerve, then branches at the knee and wraps around the outside of the fibula, where it sits directly under the skin against bone.
What a diagram cannot show is that the consequence is identical wherever the interruption happens. The muscle does not know why the message stopped. That is why the foot looks the same in every column of the table above, and why the history and the rest of the examination carry more weight here than watching someone walk.
It also explains the vulnerable spot. Where the nerve wraps the fibula there is no muscle over it and almost no padding — so an hour of pressure from a cast edge, a squat or a long operation can do what nothing else along its length would.
Nerve studies are more useful after two or three weeks than in the first few days. Changes in the muscle take time to appear, so a study done too early can look reassuring when it should not. This does not mean waiting to be seen — the examination and the scan happen first, and the timing of the nerve study is planned around them.
Two things run in parallel: keeping the foot working while the nerve recovers, and dealing with whatever is interrupting it.
A light splint inside the shoe holds the foot level so the toes clear the ground. It does not treat the cause, but it stops the trips and falls, keeps the ankle from stiffening into a pointed position, and lets you walk normally while everything else is sorted out. Worth having from the first visit rather than at the end.
Where the nerve is compressed at the knee, stopping what compresses it is often the whole treatment — no leg crossing, no prolonged squatting, padding under a cast edge. Where a disc is pressing on the L5 root, the same principle applies higher up, and that is addressed as a spinal problem.
A disc pressing hard enough on the L5 root to drop the foot is one of the clearer reasons to decompress it, and sooner rather than later. Where something is pressing on the nerve at the knee — a cyst or a growth — releasing it is a smaller operation. Which one applies follows entirely from where the interruption is.
A nerve that is compressed but intact often recovers well, over weeks to months, once the pressure is gone. A nerve that has been compressed for a long time, or damaged rather than squeezed, may recover partly or not at all — and where it does not, a tendon transfer can restore the lift by rerouting a working muscle. The honest answer at the first visit is usually that the timing and the cause together decide it.
Often, but it depends on the cause and on how long it has been there. A nerve compressed at the knee for a few weeks usually recovers well once the pressure is removed. A nerve that has been compressed for many months, or damaged rather than squeezed, may not recover fully. That is why it is worth being assessed early rather than waiting to see.
No, although a stroke can cause it. Foot drop on its own, with no weakness in the arm or face and no change in speech, is far more often a nerve problem at the knee or the spine. Foot drop that appears suddenly together with those other signs needs emergency assessment.
Usually not. The brace is there to keep you walking safely and to stop the ankle stiffening while the cause is treated and the nerve recovers. Many people come out of it. Where recovery is incomplete, it either stays as a long-term aid or a tendon transfer takes over the job.
Lying still for a long procedure puts steady pressure on the outside of the knee, exactly where the nerve is most exposed. The same thing happens after a long illness in bed, or with rapid weight loss, which removes what little padding is there.
Exercises keep the ankle moving and the calf from tightening, which matters. What they cannot do is restore a signal that is not arriving, so they sit alongside treating the cause rather than instead of it.
No. Bring any scan, nerve study or EMG reports, a note of when you first noticed it and what you were doing beforehand, and the shoes you wear most — the wear pattern is genuinely informative.
Peroneal nerve palsy · Slipped disc · Spinal stenosis · Sciatica · Neuropathic pain · Nerve and leg pain
Be ready to say when it started and what you were doing beforehand. That answer narrows the cause more than anything else.
