Tarsal tunnel syndrome is a condition where a major nerve gets compressed as it passes through a narrow passageway on the inner side of your ankle. That passageway, called the tarsal tunnel, sits just behind and below the bony bump on the inside of your ankle. When the nerve running through it gets squeezed, you feel burning, tingling, or pain in the sole of your foot.
The condition is sometimes compared to carpal tunnel syndrome in the wrist, and the mechanics are similar: a nerve gets pinched inside a tight space surrounded by bone and tough connective tissue. But tarsal tunnel syndrome is less common and often harder to diagnose, which means it can go unrecognized for months.
What Happens Inside the Tarsal Tunnel
The tarsal tunnel is a small channel formed by ankle bones on one side and a band of fibrous tissue (called the flexor retinaculum) stretching over the top like a roof. Packed inside this space are several tendons, an artery, a vein, and the posterior tibial nerve. That nerve carries both movement signals and sensation, and it eventually branches into smaller nerves that supply feeling to the heel, arch, and toes.
Because everything is packed tightly together, anything that takes up extra space or puts pressure on the nerve can trigger symptoms. Even a small amount of swelling, a tiny cyst, or a shift in foot alignment can be enough to compress the nerve against the walls of the tunnel.
Common Causes and Risk Factors
Doctors divide the causes into two broad categories: problems originating inside the tunnel itself, and forces acting on it from outside.
Inside the tunnel, the nerve can be squeezed by swollen tendons, ganglion cysts, varicose veins, lipomas (fatty growths), bone spurs, or scar tissue from a previous injury. These space-occupying structures leave less room for the nerve to function normally.
External causes include flat feet or other alignment issues that change the angle of the ankle and increase tension on the nerve. Shoes that fit poorly, especially those that press against the inner ankle, can contribute. So can ankle sprains, fractures, or any trauma that leads to swelling in the area. Systemic conditions play a role too: diabetes, inflammatory arthritis, and generalized leg swelling all raise the risk. People who have had prior ankle surgery may develop scar tissue that compresses the nerve over time.
Repetitive activities like running or prolonged standing are frequent triggers, particularly when combined with foot mechanics that already place extra strain on the inner ankle.
What Tarsal Tunnel Syndrome Feels Like
The hallmark symptoms are burning, tingling, numbness, or shooting pain along the bottom of the foot. Some people describe it as an electric or “pins and needles” sensation. The discomfort typically follows the path of the nerve, spreading from behind the inner ankle into the arch, heel, or toes.
Symptoms tend to worsen during or after physical activity, especially walking, running, or standing for long stretches. Unlike plantar fasciitis, which is worst first thing in the morning when you step out of bed, tarsal tunnel syndrome generally flares with use and may persist into the evening. Some people notice worsening pain at night, particularly if swelling accumulates throughout the day.
In more advanced cases, the numbness can become constant, and you may notice weakness in the small muscles of the foot. This can make it harder to spread your toes or feel the ground clearly underfoot.
How It Differs From Plantar Fasciitis
Because both conditions cause pain in the bottom of the foot, they’re easily confused. Plantar fasciitis is an inflammation of the thick band of tissue running along your arch. It causes a sharp, stabbing heel pain that’s typically worst with your first steps in the morning, then gradually loosens up as you move. The pain is mechanical, not nerve-related, so you won’t feel tingling or burning.
Tarsal tunnel syndrome, by contrast, produces nerve-type sensations: burning, tingling, numbness, or electric jolts. The pain tends to build with activity rather than easing with movement. If you’re experiencing numbness or a radiating, buzzing quality to the pain, that points more toward nerve compression than tissue inflammation.
How It’s Diagnosed
Diagnosis starts with a physical exam. One of the most useful bedside tests is Tinel’s sign: your doctor taps on the nerve behind your inner ankle bone. If this reproduces your tingling or sends a shock-like sensation into the sole of your foot, it’s considered a positive finding. Pressure provocation tests, where the doctor applies sustained pressure over the tarsal tunnel, are also used to see if they can recreate your symptoms.
Nerve conduction studies and electromyography (EMG) can measure how quickly electrical signals travel through the posterior tibial nerve. Abnormally slow conduction supports the diagnosis. However, these tests have limited sensitivity for tarsal tunnel syndrome, meaning they can come back normal even when the condition is present. A normal nerve study doesn’t rule it out.
Imaging, particularly MRI or ultrasound, helps identify structural causes like cysts, swollen tendons, or varicose veins inside the tunnel. This is especially important because finding a specific cause of compression improves treatment planning and, if surgery is needed, predicts better outcomes.
Conservative Treatment Options
Most people start with non-surgical management, and it often provides meaningful relief. A structured approach typically includes several components working together.
- Orthotics and supportive footwear: Custom shoe inserts help maintain a proper arch and reduce the inward rolling of the foot (pronation) that increases tension on the nerve. Stability or motion-control shoes serve a similar purpose. For people whose tarsal tunnel syndrome stems from flat feet or alignment issues, this alone can make a significant difference.
- Anti-inflammatory medication: Over-the-counter options like ibuprofen can reduce pain and swelling around the nerve.
- Physical therapy: A structured program focusing on stretching, strengthening, and range-of-motion exercises has shown solid results. One study found that all 28 patients in a six-week physiotherapy program that included stretching, strengthening exercises, and medial arch supports showed improvement in both pain and range of motion.
- Activity modification: Reducing or temporarily stopping the activities that provoke symptoms gives the nerve time to recover. This might mean cutting back on running mileage or avoiding prolonged standing.
- Corticosteroid injections: An injection into the tarsal tunnel can reduce swelling and provide temporary relief, particularly when inflammation is a major contributor.
Conservative treatment programs typically run four to six weeks before meaningful improvements are assessed, though some people notice changes sooner. The timeline varies depending on severity and the underlying cause.
When Surgery Becomes an Option
Surgery is considered when conservative treatment fails to provide adequate relief and when doctors can clearly identify what’s compressing the nerve. The procedure, called a tarsal tunnel release, involves cutting the fibrous band (retinaculum) that forms the roof of the tunnel to give the nerve more room. If a cyst, swollen vein, or other structural problem is responsible, it’s removed at the same time.
One indicator that conservative treatment may not succeed: abnormally slow nerve conduction on electrodiagnostic testing. This finding suggests the nerve is compressed enough that rest, orthotics, and therapy alone are unlikely to resolve the problem fully.
Surgical outcomes vary more than you might expect. Reported success rates range from 44% to 96% across different studies, a wide spread that reflects differences in patient selection, how long symptoms were present before surgery, and whether a specific structural cause was identified. In one study, 68% of patients were satisfied with their surgical outcome, 22% found results acceptable, and 10% were dissatisfied. Patients with a clearly identifiable and correctable cause of compression tend to do best. Those with vague or longstanding symptoms and no obvious structural problem have less predictable results.
Factors That Affect Your Outlook
Early recognition matters. The longer the nerve stays compressed, the more likely it is to sustain damage that doesn’t fully reverse, even after the pressure is relieved. People who seek treatment within the first few months of symptoms generally respond better to both conservative care and surgery than those who wait a year or more.
The underlying cause also shapes the outlook significantly. Tarsal tunnel syndrome triggered by a single identifiable problem, like a ganglion cyst or a specific alignment issue that orthotics can correct, tends to respond well to targeted treatment. Cases driven by systemic conditions like diabetes or inflammatory arthritis may require ongoing management of the underlying disease alongside local treatment of the ankle.
If you have flat feet or tend to overpronate, wearing supportive footwear consistently, not just during exercise, helps reduce the mechanical strain that contributes to nerve compression over time.