Morton’s Neuroma (MN) is a painful foot condition resulting from the irritation and subsequent thickening of nerve tissue, most commonly between the third and fourth toes. The primary symptoms include a sharp, burning pain in the ball of the foot, numbness or tingling in the affected toes, and the distinctive sensation of walking on a small pebble or marble. Because these symptoms are often vague and localized to the forefoot, they can be easily confused with other common foot ailments. Understanding the subtle differences between MN and its look-alike conditions is important for achieving an accurate diagnosis and effective treatment plan.
Structural Conditions of the Metatarsals
Pain in the forefoot is frequently attributed to issues involving the bones and joints, which can be mistaken for the nerve-related pain of Morton’s Neuroma.
Metatarsal Stress Fracture
A metatarsal stress fracture involves tiny hairline cracks in one of the long bones of the foot. Unlike the interdigital nerve pain of MN, a stress fracture typically causes a dull, persistent ache that intensifies with weight-bearing activities like running or walking. The pain from a stress fracture is often localized directly to the bone, and visible swelling may appear on the top of the foot, which is rare with a neuroma. Imaging, such as X-rays or a bone scan, is necessary to confirm the presence of a bone injury and rule out a nerve issue.
Capsulitis
Another structural issue is capsulitis, which is the inflammation of the joint capsule and ligaments surrounding a metatarsophalangeal joint, most often the second toe joint. Capsulitis causes sharp pain and tenderness localized to a single joint, and movement of that toe joint will usually aggravate the discomfort. This differs from the radiating, often burning pain of MN, which is centered in the web space between the toes rather than directly in the joint itself. While both conditions cause forefoot pain, capsulitis represents a mechanical joint problem, whereas MN is specifically a thickening of the nerve tissue.
Intermetatarsal Bursitis
Intermetatarsal bursitis is a condition that closely mimics Morton’s Neuroma because it occurs in the exact same anatomical location—the web space between the metatarsal heads. A bursa is a small, fluid-filled sac that functions to reduce friction between tissues, but when it becomes inflamed, it swells, a condition known as bursitis. This swollen bursa can then put direct pressure on the adjacent interdigital nerve, leading to symptoms that closely resemble a neuroma.
The symptoms of bursitis, including pain, a burning sensation, and the feeling of stepping on a stone, are nearly indistinguishable from those of MN during a physical exam. Both conditions can even produce a positive “Mulder’s click,” a clicking sensation felt when the foot is squeezed, making a clinical diagnosis challenging. The primary pathological difference is that bursitis is the inflammation of the fluid sac, while MN is the actual thickening of the nerve tissue itself.
Due to the significant symptomatic overlap, advanced diagnostic imaging, particularly ultrasound or Magnetic Resonance Imaging (MRI), is often required to definitively differentiate between the two. Imaging can reveal the specific nature of the soft tissue mass—whether it is a fluid-filled bursa or a solid, thickened nerve. Treatment for both conditions is often similar initially, involving anti-inflammatory measures and specialized footwear, but surgical treatment options differ based on the precise pathology.
Proximal Nerve Entrapment Syndromes
Nerve pain that originates far from the foot but is felt in the forefoot can also be misdiagnosed as Morton’s Neuroma, falling under the umbrella of proximal nerve entrapment syndromes.
Tarsal Tunnel Syndrome (TTS)
Tarsal Tunnel Syndrome (TTS) involves the compression of the posterior tibial nerve as it passes through a narrow tunnel on the inside of the ankle. This compression causes burning, tingling, and numbness, but the pattern is often much more diffuse than a neuroma. While MN pain is strictly localized to one or two toe web spaces, TTS symptoms frequently affect the entire sole of the foot, the heel, and sometimes radiate up the calf. A physical exam can often distinguish TTS using Tinel’s sign, where tapping over the compressed nerve at the ankle elicits a tingling sensation in the foot, a finding absent in MN. The source of the nerve irritation is the ankle, whereas MN is solely a forefoot issue.
Lumbar Radiculopathy (Sciatica)
Pain can also be referred from the lower back due to lumbar radiculopathy, commonly known as sciatica or a pinched nerve in the spine. When a nerve root in the lumbar spine is compressed, perhaps by a herniated disc, it can send referred pain, numbness, and tingling down the leg and into the foot. This distal foot pain may be mistaken for a localized problem like MN, but the source is structural irritation at the spine. A key indicator of lumbar radiculopathy is the presence of accompanying back or hip pain, and the foot symptoms tend to follow a specific dermatomal pattern. Unlike the sharp, localized forefoot pain of MN, radiculopathy-related foot symptoms may worsen with prolonged sitting, coughing, or bending, and they often present as a radiating pain that travels down the limb. A thorough history and clinical testing for spinal involvement are necessary to avoid misattributing this remote nerve compression to a localized neuroma.