Interdigital Neuralgia (Morton’s Neuroma)

When nerves between the toes become irritated

Tingling, burning, or stabbing pain in the forefoot can significantly impact daily activities. One possible cause is interdigital neuralgia – a painful nerve irritation between the toes. This condition is also referred to as Morton’s neuroma, although it does not involve an actual tumor. Instead, it describes a thickened sensory nerve, usually located between the third and fourth toes.

What is interdigital neuralgia?

Interdigital neuralgia occurs when a sensory nerve between the metatarsal bones (long bones in the forefoot) becomes irritated. This often leads to persistent or activity-related pain, which can worsen when wearing tight shoes or standing for long periods. The condition is not dangerous, but it can be extremely uncomfortable.

Schematic top view of a left foot with a drawn Morton’s neuroma (interdigital neuralgia) between the third and fourth toe rays. — A Morton’s neuroma – thickening of a sensory nerve in interdigital neuralgia – between the third and fourth toe rays as a potential cause of forefoot pain.

What causes the symptoms?

The forefoot is a narrow area where nerves, bones, and ligaments lie very close together. If too much pressure is exerted on a nerve, it can become compressed and irritated. This leads to a type of nerve damage that causes the nerve to thicken – commonly referred to as Morton’s neuroma.

Despite the name, this is not a tumor. A neuroma is a benign thickening of a nerve, whereas a neurinoma would be a true nerve tumor. In interdigital neuralgia, a thickened sensory nerve is the cause of the symptoms.

Typical symptoms

The following signs often suggest interdigital neuralgia:

Burning or stabbing pain in the ball of the foot
Numbness or tingling between the toes
Discomfort when walking, especially in tight shoes
The sensation of a small stone under the forefoot

Cartoon-style illustration of a right foot from above with a highlighted pain area in the forefoot, indicating Morton’s neuroma (interdigital neuralgia) between the third and fourth toe rays. — Typical pain area in Morton’s neuroma: A pinched nerve between the third and fourth toe rays of the right foot can cause burning, stabbing forefoot pain.

The symptoms may appear intermittently or persist over time. In some cases, both feet may be affected.

Clinical signs

Doctors often identify interdigital neuralgia based on typical symptoms and specific examination findings. These may include:

Localized tenderness in the space between the metatarsal heads
A thickened nerve that may be palpable or move when pressure is applied from the side (Mulder’s sign)

Although these findings are not always present, they can provide important clues for diagnosis.

Ultrasound for direct nerve imaging

In experienced hands, ultrasound provides a gentle and precise way to visualize the interdigital nerves – without radiation or needles. The examination is performed directly on the forefoot and allows for real-time assessment of nerve structure and mobility.

Illustration of a high-resolution ultrasound probe for visualizing peripheral nerves. — High-resolution probes can help visualize fine nerve structures in detail.

Ultrasound can help identify nerve swelling or surrounding tissue changes and may even detect movement or displacement of the nerve during dynamic testing. This makes it particularly valuable when symptoms are present but other tests are inconclusive.

Role of electrodiagnostic testing

Electrophysiological tests such as nerve conduction studies (NCS) and electromyography (EMG) are not usually helpful in diagnosing interdigital neuralgia. This is because the affected nerves are purely sensory, very short, and located superficially.

These methods can be useful in certain differential diagnoses, such as generalized polyneuropathy or more proximal nerve damage – but they rarely provide conclusive results in Morton’s neuroma itself.

Additional imaging

In certain cases, magnetic resonance imaging (MRI) may be useful, especially if the ultrasound does not show clear findings or if other foot disorders are suspected. MRI can reveal swelling, soft tissue changes, or unusual lesions, though it is generally more expensive and less dynamic than ultrasound.

Why precise diagnosis matters

A clear diagnosis is essential for choosing the right treatment. When a thickened nerve is visualized with high-resolution imaging, a tailored treatment plan can be developed. This may include shoe modifications, physiotherapy, or further evaluation by a specialist if symptoms persist.

Conclusion

Interdigital neuralgia is a painful but often underrecognized cause of forefoot discomfort. When clinical examination and high-resolution ultrasound are used together, a reliable diagnosis can often be achieved.

Early evaluation helps avoid misdiagnosis and supports a targeted, gentle approach to managing the condition.

Disclaimer: The information provided on this page is for general informational purposes only and does not constitute medical advice. It is not a substitute for personal consultation, examination, or treatment by a physician or other qualified healthcare professional. No guarantees of healing or cure are made. While we strive for accuracy and completeness, we cannot guarantee that all content is up to date or free from errors, and we accept no liability for any inaccuracies.