Diagnostic Evaluation of Upper‑Limb Numbness and Tingling (C7/ulnar distribution)

1. Initial Electrodiagnostic Testing

• Perform nerve conduction studies and electromyography first to differentiate C7 cervical radiculopathy from ulnar neuropathy at the elbow; proceed to cervical spine MRI only if radiculopathy is suspected or symptoms persist despite normal electrodiagnostic results. – American College of Radiology 1
• Electrodiagnostic studies can also identify brachial plexopathy as a distinct entity, separating it from radiculopathy or peripheral nerve compression. – American College of Radiology 4
• Electrodiagnostic testing is useful for detecting polyneuropathy when the clinical picture is unclear. – Praxis Medical Insights 2

2. Red‑Flag Clinical Features Requiring Urgent Imaging

• Progressive motor weakness is a red flag that mandates prompt imaging to exclude serious pathology. – Praxis Medical Insights 2
• Constitutional symptoms such as fever or unexplained weight loss constitute red flags and should trigger urgent imaging. – Praxis Medical Insights 2
• A history of malignancy is a red flag indicating the need for immediate imaging to rule out metastatic involvement. – American College of Radiology 3

3. Advanced Imaging Recommendations

• When brachial plexopathy is suspected, obtain dedicated MRI of the brachial plexus using orthogonal oblique planes and T1, T2, fat‑saturated T2, and fat‑saturated T1 post‑contrast sequences. – American College of Radiology 1
• Standard cervical spine MRI without dedicated plexus views may miss brachial plexus pathology; therefore, dedicated plexus imaging is required in such cases. – American College of Radiology 1

4. Indications for Brachial Plexus Imaging

• Consider brachial plexus MRI when electrodiagnostic studies suggest plexopathy rather than radiculopathy or peripheral nerve entrapment, when scapular pain is prominent with multi‑nerve‑territory involvement, or when symptom distribution does not fit typical radiculopathy patterns. – American College of Radiology 5, American College of Radiology 1, American College of Radiology 3

5. Evaluation of Neurogenic Thoracic Outlet Syndrome (TOS)

• Neurogenic TOS should be considered if symptoms involve the C8‑T1 distribution; MRI of the chest (without contrast) can assess the costoclavicular and interscalene spaces for compressive lesions. – American College of Radiology 5, American College of Radiology 4

All statements are based on cited evidence; strength of evidence was not specified in the source material.