What are the key physical examination findings for Morton's neuroma?

Physical Examination Findings for Morton's Neuroma

The thumb-index finger squeeze test (modified webspace tenderness test) is the most sensitive clinical examination finding for Morton's neuroma, with 96% sensitivity, and should be your primary screening test 1, 2.

Key Physical Examination Tests

High-Yield Positive Findings

Webspace Tenderness (Thumb-Index Finger Squeeze Test)

• Sensitivity: 95-96% with a negative likelihood ratio of 0.04, making it excellent for ruling out Morton's neuroma when negative 1, 3, 2
• Technique: Direct compression of the affected intermetatarsal space using thumb and index finger
• Present in 95% of surgically confirmed cases 3

Mulder's Click

• Specificity increases with larger neuromas (significantly larger at 10.9 mm vs 8.5 mm when positive, p=0.016) 2
• Sensitivity: 61% 3, 2
• This is the most specific clinical sign when present, but its absence does not rule out the diagnosis

Foot Squeeze Test

• Sensitivity: 41-88% (variable across studies) 3, 2
• Technique: Lateral compression of the metatarsal heads
• Less reliable than webspace tenderness but supportive when positive

Subjective Features with Diagnostic Value

Patient-Reported "Clicking"

• Highly specific (96%) with positive likelihood ratio of 13.14 1
• When a patient reports clicking, this essentially rules in Morton's neuroma
• This is distinct from the examiner eliciting Mulder's click

Common but Less Specific Symptoms

• "Walking on a pebble" sensation: 43-53% sensitivity, 52% specificity 1
• Burning pain: 54-57% sensitivity, 48% specificity 1
• These symptoms are supportive but insufficient alone for diagnosis

Lower-Yield Examination Findings

Percussion Tests

• Plantar percussion: 37-61% sensitivity 3, 2
• Dorsal percussion: 26-33% sensitivity 2
• These have poor diagnostic accuracy and should not be relied upon

Neurological Testing

• Toe tip sensation deficit: 26-67% sensitivity 3, 2
• Critical caveat: Sensation deficits occur equally in asymptomatic and symptomatic neuromas 3
• Only meaningful when combined with other positive tests

Clinical Algorithm for Diagnosis

1. Start with webspace tenderness test - if negative, Morton's neuroma is unlikely (NPV 96%)
2. Ask specifically about clicking - if patient reports this, diagnosis is highly likely (specificity 96%)
3. Attempt to elicit Mulder's click - positive finding increases confidence, especially if neuroma is larger
4. Assess for pain on weight-bearing (91% of cases) that is relieved by rest (81% of cases) 4

Important Clinical Pearls

Clinical examination has 98% sensitivity when properly performed, comparable to ultrasound (90%) and MRI (88%) 4. This means imaging is not absolutely required when clinical findings are clear.

Imaging indications 4:

• Unclear clinical assessment
• Multiple webspaces affected
• Confirmation before intervention

Common pitfall: Do not rely on sensation testing alone - it cannot distinguish symptomatic from asymptomatic neuromas 3. Sensation deficits must be combined with other positive findings to be meaningful.

Location: Most commonly affects the third intermetatarsal space, less commonly the second 5, 6.

The combination of positive webspace tenderness (ruling out when negative) and patient-reported clicking (ruling in when positive) provides the strongest diagnostic accuracy from physical examination alone 1.