Left Arm Pain with Normal Cervical MRI
Despite a normal cervical MRI, your left arm pain most likely represents cervical radiculopathy that was missed on imaging, or alternatively a brachial plexopathy that requires different imaging to diagnose.
Understanding Why MRI Can Be Normal Despite Real Pain
The 2025 ACR guidelines explicitly warn that MRI demonstrates frequent false-negative findings and abnormalities don't always correspond to clinical symptoms 1. In fact, MRI alone should never be used to diagnose cervical radiculopathy—it must be interpreted with clinical findings 1. Research confirms this limitation: only 31% of patients with cervical radiculopathy show agreement between clinical examination and MRI findings, with another 28% showing pathology at an adjacent level 2.
Most Likely Causes to Consider
Cervical Radiculopathy (Most Common)
- Affects 83 per 100,000 people annually 1
- Caused by nerve root compression from:
- Soft disc herniation
- Hard disc (bone spurs from facet or uncovertebral joints)
- Combination of both 1
- 75-90% resolve with conservative treatment 1
Critical pitfall: Your MRI may have missed the pathology because:
- Standard MRI positioning (lying down) may not reproduce the compression that occurs with neck extension or weight-bearing 3
- The affected level may be adjacent to what was imaged
- Osseous structures (bone spurs) causing compression are better seen on CT 1
Brachial Plexopathy (If Cervical Spine Truly Normal)
If your symptoms don't follow a single nerve root pattern, consider brachial plexus pathology 4. This includes:
- Thoracic outlet syndrome from cervical bands or scalene muscle abnormalities 5
- Nerve compression lateral to the spine that cervical MRI doesn't visualize 4
Key distinguishing feature: Brachial plexopathy affects multiple nerve roots simultaneously and won't show on cervical spine MRI 4.
Next Steps for Diagnosis
1. Clinical Correlation is Essential
Look for specific patterns:
- Which fingers are numb? (C6 = thumb/index; C7 = middle finger; C8 = ring/pinky)
- Specific muscle weakness patterns
- Spurling test (neck extension with rotation toward painful side)
- Shoulder abduction relief test 6
2. Consider Additional Imaging
If cervical radiculopathy suspected:
- CT cervical spine without contrast to evaluate bone spurs, uncovertebral joints, and facet joints that compress nerves 1
- CT myelography if MRI contraindicated or equivocal—offers higher spatial resolution for nerve roots 1
If brachial plexopathy suspected:
- MRI brachial plexus (not cervical spine) with sensitivity of 81% and specificity of 91% 4
- This directly visualizes the plexus lateral to the spine where cervical MRI cannot see 4
3. Electrodiagnostic Testing
While not quantifying pain, EMG/nerve conduction studies can:
- Localize the level of nerve involvement
- Differentiate radiculopathy from plexopathy
- Detect nerve damage 7, 6
Treatment Approach
Conservative Management (First-Line)
Since 75-90% improve without surgery 1:
- Exercise therapy (with or without other treatments) 6
- Physical therapy
- Time (many cases are self-limiting)
Important caveat: Evidence for medications (NSAIDs, gabapentin, pregabalin) is surprisingly limited for cervical radicular pain specifically 7, 6.
Interventional Options (If Conservative Fails)
For acute/subacute pain (<3 months):
- Interlaminar epidural corticosteroid injection (recommended 2B+) 7, 6
- Avoid transforaminal approach due to serious adverse events 7
For chronic pain (>3 months):
- Pulsed radiofrequency treatment adjacent to dorsal root ganglion (recommended 1B+) 7
- Epidural steroids have limited efficacy in chronic cases 6
- Conventional radiofrequency if pulsed RF insufficient 7
Critical Red Flags Requiring Urgent Evaluation
If you have any of these, imaging interpretation changes:
- Progressive weakness
- Bowel/bladder dysfunction
- Fever or unexplained weight loss
- History of cancer
- Severe trauma
Bottom Line
Your normal cervical MRI does not exclude cervical radiculopathy as the cause of your left arm pain 1. The imaging limitations are well-documented, with frequent false-negatives and poor correlation between MRI findings and symptoms. Consider CT imaging to evaluate bony compression, or MRI brachial plexus if symptoms suggest plexopathy rather than single-root radiculopathy. Most importantly, diagnosis requires integrating clinical examination findings with imaging—neither alone is sufficient 1.