Tarsal tunnel syndrome is a condition where the main nerve running behind your inner ankle gets compressed as it passes through a narrow space called the tarsal tunnel. This compression causes pain, burning, tingling, or numbness in the bottom of your foot and toes. It’s sometimes called the foot’s version of carpal tunnel syndrome, since both involve a nerve being squeezed inside a tight passageway.
The tarsal tunnel itself is a small channel formed by bone on one side and a band of tough tissue (called the flexor retinaculum) on the other. The posterior tibial nerve passes through this channel along with several tendons and blood vessels. When anything narrows that already-tight space or causes swelling inside it, the nerve gets pinched, and symptoms follow.
What It Feels Like
The hallmark of tarsal tunnel syndrome is nerve-type pain rather than the aching you’d feel from a muscle or ligament injury. People typically describe a burning sensation, sharp or electric jolts, or a pins-and-needles feeling along the inside of the ankle and the sole of the foot. The sensations can radiate into the toes. Some people also notice numbness or a vague sense that their foot feels “different” when they touch it.
Symptoms tend to get worse with prolonged standing or walking. But unlike many musculoskeletal foot problems, tarsal tunnel syndrome can also flare up at rest, especially in the evening or at night. In more advanced cases, the foot muscles may weaken, making it harder to spread your toes or push off while walking.
Common Causes and Risk Factors
Anything that takes up space inside the tarsal tunnel or increases pressure on the nerve can trigger the syndrome. The most common culprit is a ganglion cyst, a fluid-filled sac that forms near a joint or tendon. Other growths like lipomas or nerve sheath tumors can do the same thing. Varicose veins inside the tunnel are another frequent cause.
Flat feet (pes planus) put the nerve at risk because the foot’s inward collapse stretches and strains the nerve with every step. Ankle injuries, including sprains and fractures of the heel or ankle bones, can compress the nerve through scar tissue or displaced bone fragments. Inflammatory conditions like tenosynovitis, where the tendons running through the tunnel swell, also crowd the nerve.
Several systemic conditions raise the risk: diabetes, hypothyroidism, obesity, and other metabolic disorders can make nerves more vulnerable to compression or increase swelling in the tunnel. In a significant number of cases, no clear cause is ever identified. These idiopathic cases can be more frustrating to treat.
How It Differs From Plantar Fasciitis
Tarsal tunnel syndrome and plantar fasciitis both cause foot pain, so they’re frequently confused. The distinction matters because treatment is different for each. Plantar fasciitis produces a sharp, stabbing heel pain that’s worst with your first steps in the morning, then gradually eases as you move around. It doesn’t cause tingling, numbness, or burning. The pain stays localized near the heel.
Tarsal tunnel syndrome, by contrast, spreads across the sole and into the toes with that characteristic nerve quality: electric, burning, or prickling. It often worsens throughout the day rather than improving with movement, and it can bother you even when you’re sitting or lying down. If you’re experiencing numbness or tingling alongside your foot pain, that’s a strong signal that a nerve, not a ligament, is the source of the problem.
How It’s Diagnosed
Diagnosis usually starts with a physical exam. Your doctor will tap along the inside of your ankle over the tarsal tunnel. If this reproduces your tingling or pain shooting into the foot, that’s a positive Tinel’s sign, one of the primary screening tests. It’s useful but not perfect: studies have found it picks up the condition only about 58% of the time, so a negative result doesn’t rule it out.
Nerve conduction studies and electromyography (EMG) measure how well the nerve transmits signals through the tunnel. These tests can confirm the diagnosis and help pinpoint exactly where the compression is occurring. Imaging, usually an MRI or ultrasound, is often ordered to look for a cyst, tumor, varicose vein, or other structural cause inside the tunnel. Identifying a specific lesion is important because it influences both treatment strategy and prognosis.
Non-Surgical Treatment
Most people start with conservative management. Rest is the foundation: avoiding activities that provoke symptoms gives the nerve time to calm down. Anti-inflammatory medications help reduce swelling around the nerve. Wearing soft, supportive shoes can minimize the mechanical stress on the tunnel, and custom orthotics are particularly helpful for people with flat feet because they correct the foot position that’s stretching the nerve.
Bracing or taping the ankle can also reduce inflammation by limiting the movement that irritates the nerve. Some people benefit from corticosteroid injections into the tarsal tunnel to shrink swelling. Physical therapy focused on nerve gliding exercises and stretches for the calf and ankle may improve symptoms over time. Many patients with mild cases heal with these measures alone.
When Surgery Is Considered
If conservative treatment hasn’t provided relief after several months, or if imaging reveals a cyst, tumor, or other mass compressing the nerve, surgery becomes an option. The procedure, called a tarsal tunnel release, involves cutting the band of tissue that forms the roof of the tunnel to give the nerve more room. If a mass is present, it’s removed at the same time.
Surgical outcomes vary considerably depending on the underlying cause. When a specific lesion is found and removed, studies report improvement in 72% to 95% of patients. The picture is less clear for cases without an identifiable structural cause. Some research puts long-term success rates for idiopathic and post-traumatic cases at only 44% to 51%, leading many surgeons to recommend caution before operating when no clear lesion is present.
A recent study tracking patient-reported outcomes after tarsal tunnel release found that 62% of patients experienced a meaningful reduction in pain, and 69% reported improvement in depression symptoms that had accompanied their chronic pain. Physical function improved meaningfully in about 35% of patients. These numbers reinforce that surgery can help, especially when the right candidate is selected, but it isn’t a guarantee.
What Affects Your Outcome
The single biggest factor in how well treatment works is whether a specific, treatable cause is identified. A ganglion cyst that can be removed, a bone fragment that can be cleared, or flat feet that can be corrected with orthotics all give treatment a clear target. Idiopathic cases, where the nerve is compressed for no obvious reason, respond less predictably to both conservative care and surgery.
How long you’ve had symptoms also matters. Prolonged nerve compression can cause lasting damage to the nerve fibers, which means the numbness or weakness may not fully reverse even after the pressure is relieved. Early evaluation gives you the best chance of a complete recovery, particularly if the problem turns out to be something structural that can be addressed directly.