Tarsal tunnel syndrome is diagnosed through a combination of physical examination, nerve conduction studies, and imaging, but there is no single standardized test that confirms it. That lack of a universal diagnostic standard is part of what makes this condition tricky. Your doctor will piece together your symptoms, hands-on exam findings, and test results to build the case for or against the diagnosis.
What Your Doctor Looks and Feels For
The physical exam is the starting point and often the most informative step. Your doctor will examine your feet for visible clues: muscle wasting (particularly in the small muscles of the sole), flat foot posture, toe deformities, swelling along the inner ankle, or any palpable lump near the ankle bone. Flat feet matter because they can stretch the nerve running through the tarsal tunnel, so foot alignment is part of the assessment. You may be asked to stand or walk so your doctor can observe how your foot hits the ground, looking for excessive rolling inward or an altered gait that suggests you’re favoring the affected side.
The nerve at the center of this condition is the posterior tibial nerve, which passes through a narrow channel on the inner side of your ankle before branching into the sole of your foot. Where your symptoms show up helps pinpoint which branch is compressed. Burning or numbness along the inner sole suggests the medial plantar branch. Symptoms along the outer sole and smallest toes point to the lateral plantar branch. Pain isolated to the heel implicates the calcaneal branch. Your doctor will ask you to describe exactly where the discomfort is and map it against these known patterns.
Tinel’s Sign and the Dorsiflexion-Eversion Test
Two specific physical maneuvers help provoke your symptoms in a controlled way. The first is Tinel’s sign: your doctor taps the skin over the posterior tibial nerve along the inside of your ankle and asks what you feel. If tapping reproduces tingling, shooting pain, or numbness radiating into your foot, that’s considered a positive result and supports the diagnosis.
The second is the dorsiflexion-eversion test. Your doctor positions your foot so the toes point upward (dorsiflexion) while the sole turns outward (eversion), then holds that position for 5 to 10 seconds. This combination stretches and compresses the nerve inside the tunnel. If it reproduces your typical burning, tingling, or pain, the test is positive. Neither test is perfect on its own, but a positive result on both adds significant weight to the diagnosis.
Nerve Conduction Studies and EMG
Electrodiagnostic testing measures how well the posterior tibial nerve conducts electrical signals. During a nerve conduction study, small electrical impulses are applied to the nerve and sensors measure how fast and how strongly the signal travels. Slower-than-normal conduction velocity across the tarsal tunnel suggests compression at that site. An electromyography (EMG) test, often done at the same visit, uses a thin needle electrode in the foot muscles to check whether the nerve is delivering signals properly to the muscles it controls.
These tests serve two purposes. They can confirm that a nerve problem exists, and they can help rule out other conditions that mimic tarsal tunnel syndrome, such as a pinched nerve in the lower back. However, a normal result doesn’t necessarily rule out tarsal tunnel syndrome, especially in mild or early cases. The American College of Foot and Ankle Surgeons has noted that electrodiagnostic studies are relevant for treatment planning, but no single threshold on these tests definitively confirms or excludes the diagnosis.
Imaging: MRI and Ultrasound
Imaging is used primarily to find what’s causing the compression. An MRI of the ankle can reveal space-occupying lesions inside the tarsal tunnel, such as ganglion cysts, nerve tumors, inflamed tendon sheaths, or scar tissue from a previous injury. In one study examining symptomatic patients with MRI, every case had an identifiable mechanical cause of compression, including nerve sheath tumors, tendon inflammation, ganglion cysts, and post-traumatic scarring.
Ultrasound offers a faster, less expensive alternative and can detect cysts, varicose veins, or swollen tendons pressing on the nerve. It also allows the doctor to watch the nerve in real time as you move your foot. Standing X-rays of the foot and ankle may be ordered to evaluate bone-related causes like fractures, bone spurs, or abnormal foot alignment that could be contributing to the problem.
How It Differs From Plantar Fasciitis
Tarsal tunnel syndrome is frequently confused with plantar fasciitis because both cause foot pain, but the symptom patterns are distinct. Plantar fasciitis produces a sharp, stabbing heel pain that is worst with your first steps in the morning and gradually loosens up as the tissue stretches. It’s an inflammation of the thick band of tissue on the bottom of your foot, not a nerve problem.
Tarsal tunnel syndrome, by contrast, causes burning, tingling, or numbness across the sole that typically worsens during or after physical activity rather than first thing in the morning. The nerve-related quality of the pain (electric, buzzing, or “pins and needles”) is the key distinguishing feature. If your symptoms include numbness or a sensation that your foot is “falling asleep,” that points toward a nerve issue rather than a tissue inflammation problem. Some people have both conditions simultaneously, which complicates the picture, but the presence of true neurological symptoms like tingling or numbness is what steers the workup toward tarsal tunnel syndrome.
Why Diagnosis Can Take Time
There is no universally accepted diagnostic checklist for tarsal tunnel syndrome. Unlike some conditions where a single blood test or imaging finding seals the diagnosis, tarsal tunnel syndrome requires your doctor to weigh multiple pieces of evidence together: your symptom description, which physical tests are positive, what electrodiagnostic studies show, and whether imaging reveals a structural cause. Each piece alone can be inconclusive. A positive Tinel’s sign is suggestive but not definitive. Nerve conduction studies can be normal in early cases. An MRI might show a cyst, but a cyst doesn’t always cause symptoms.
This is why some people see multiple specialists before getting a clear answer. If your initial evaluation is inconclusive, a referral to a neurologist for electrodiagnostic testing or to a foot and ankle specialist for advanced imaging is a reasonable next step. The diagnosis ultimately rests on a consistent story: symptoms that match the nerve’s territory, physical exam findings that reproduce those symptoms, and ideally objective evidence from nerve testing or imaging that explains the compression.