Drop Foot
Drop foot happens when the muscles that lift the front of the foot become weak or paralyzed, often because nerve damage, muscle problems, or brain and spinal cord conditions interfere with their function. This weakness makes it hard to raise the toes, which can cause tripping or an unusual walking pattern. The problem itself is a symptom of another condition, not a disease on its own.
Issues such as peroneal nerve injury, nerve compression in the spine, stroke, multiple sclerosis, or certain muscle diseases can cause drop foot. Non-medical factors like prolonged leg crossing, wearing a tight cast, or direct injury to the leg can also trigger it. Understanding the cause is important because treatment depends on the underlying problem.
Definition of Symptom
Foot drop, also called drop foot, is a movement problem where a person cannot lift the front part of the foot. This makes the toes point downward when the foot is at rest. Weakness or paralysis in the muscles that control lifting the foot causes the foot to drag during walking.
This symptom can affect one foot (unilateral) or both feet (bilateral). It is not a disease by itself but a sign of another condition affecting the nerves, muscles, or brain. Key features of foot drop include:
- Difficulty lifting the front of the foot.
- Toes dragging on the ground when walking.
- A higher-than-normal step to avoid tripping (steppage gait).
| Term | Meaning |
|---|---|
| Foot Drop | Inability to lift the front of the foot properly. |
| Dorsiflexion | Upward movement of the foot at the ankle. |
| Drop Foot | Another name for foot drop. |
Foot drop can be temporary or permanent, depending on the cause. Some people may use a brace or splint to keep the foot in a normal position. The condition can reduce walking stability and increase the risk of falls.
Possible Causes/Diseases Condition
Problems affecting the nerves, muscles, or brain often cause drop foot. Neurological conditions commonly cause drop foot, such as:
- Stroke – when brain areas controlling foot movement become damaged.
- Multiple sclerosis (MS) – when the immune system attacks the nervous system.
- Amyotrophic lateral sclerosis (ALS) and other motor neuron diseases – when nerve cells controlling muscles are lost over time.
- Polio – when a virus damages motor nerves.
Peripheral nerve problems can also cause drop foot. Examples include:
- Peroneal nerve injury from knee dislocation or leg trauma.
- Charcot-Marie-Tooth disease – an inherited nerve disorder that weakens muscles.
- Nerve compression from prolonged leg crossing, casts, or tight boots.
Spinal causes may involve:
- Lumbar disc herniation or herniated disc pressing on nerves.
- Spinal injuries or degenerative changes affecting nerve roots.
Metabolic and systemic disorders such as diabetes can damage peripheral nerves over time, leading to weakness in the foot and ankle muscles. The table below summarizes some possible causes:
| Category | Example Conditions |
|---|---|
| Neurological | Stroke, MS, ALS, Polio |
| Peripheral Nerve Injury | Peroneal nerve injury, Charcot-Marie-Tooth |
| Spinal | Lumbar disc herniation, nerve root compression |
| Metabolic/Systemic | Diabetes-related neuropathy |
Other Non-Disease Causes
Drop foot can also result from factors not linked to illness or long-term medical conditions. These causes often involve temporary nerve compression or muscle weakness. Crossing the legs for extended periods can put pressure on the peroneal nerve along the outer knee. This pressure may reduce nerve function and cause temporary weakness in the muscles that lift the foot.
Prolonged kneeling or squatting can have a similar effect. Activities such as gardening, certain work tasks, or specific exercises may lead to short-term nerve compression. Significant weight loss in a short period can reduce the fat padding around nerves. This may make them more vulnerable to pressure from positions or movements that were not a problem before. Other possible triggers include:
- Wearing tight boots or casts
- Sitting in one position for long periods
- Sleeping in a posture that compresses the leg
| Cause | How It Affects the Nerve |
|---|---|
| Leg crossing | Compresses peroneal nerve. |
| Rapid weight loss | Less cushioning for nerve. |
| Prolonged squatting | Sustained nerve compression. |
How It Causes the Symptom
When the muscles that lift the front of the foot become weak or stop working, drop foot occurs. Nerve damage or injury often interrupts signals between the brain, spinal cord, and foot muscles. The common peroneal nerve, which runs along the outside of the knee and controls muscles that lift the foot, is most often involved. Injury or compression here can cause the toes to drag while walking.
Damage can also happen higher up the leg or in the back. The sciatic nerve, which branches into the common peroneal nerve, can be affected by trauma, surgery, or prolonged pressure, leading to similar symptoms. Possible causes of nerve injury include:
- Direct blows to the outside of the knee.
- Prolonged leg crossing or squatting.
- Surgery near the hip or knee.
- Nerve compression from swelling or masses.
Muscle damage can also play a role. If the muscles that lift the foot are injured, wasted, or weakened from disease, the foot may not clear the ground during walking. Sometimes, problems in the spine, such as a herniated disc pressing on nerve roots, can disrupt movement signals to the foot.
| Nerve Involved | Common Effect on Movement |
|---|---|
| Common peroneal nerve | Weakness lifting foot |
| Sciatic nerve | Weakness in leg and foot |
Possible Complications
Foot drop can change walking patterns. People may lift their knees higher than normal to avoid dragging their toes, which can cause muscle strain in the legs and hips. Over time, this altered way of walking may lead to joint discomfort. An increased risk of falls can result from weak foot lift, making tripping more likely, especially on uneven surfaces or stairs. Falls can cause bruises, sprains, or fractures.
Using a brace can sometimes cause skin problems. Pressure from the device can cause irritation, redness, or sores, especially if it does not fit well. Nerve damage that causes foot drop can sometimes weaken other muscles in the leg. This may lead to reduced movement and make daily activities, such as climbing stairs or walking long distances, more difficult. The table below shows some possible complications and their common causes:
| Complication | Possible Cause |
|---|---|
| Falls and injuries | Weak foot lift, tripping on uneven ground. |
| Joint pain | Altered gait and muscle overuse. |
| Skin irritation | Ill-fitting brace or prolonged device use. |
| Reduced mobility | Progression of underlying nerve or muscle damage. |
When to Seek Medical Attention
See a doctor if you notice difficulty lifting the front of your foot or drag your toes when walking. Muscle weakness or nerve problems can cause these symptoms and need prompt evaluation.
Get medical help if foot drop develops suddenly, especially after an injury or without a clear cause. Sudden onset may signal nerve damage, stroke, or other serious conditions. Seek care right away if foot drop occurs with any of the following:
- Numbness or tingling in the leg or foot.
- Weakness in other parts of the body.
- Severe or worsening pain.
- Loss of bladder or bowel control.
If symptoms get worse over days or weeks, this may point to an underlying problem that needs treatment to prevent further loss of function. A healthcare provider can run tests to find the cause, such as nerve checks, scans, or blood tests.
Early diagnosis helps improve the chances of managing or reversing the problem. Even temporary or mild foot drop should be checked if it affects walking or balance. This lowers the risk of falls and other problems.
