Can a tingling sensation in the inner left scapula, accompanied by weakness in the left hand, indicate brachial plexus (nerve network that originates in the spinal cord) involvement in an adult patient, possibly with underlying conditions such as cervical spondylosis (wear and tear on the discs in the neck) or a history of trauma?

Can Tingling in the Inner Scapula Indicate Brachial Plexus Involvement?

Yes, tingling in the inner left scapula accompanied by left hand weakness can indicate brachial plexus involvement, but this presentation requires careful differentiation from cervical radiculopathy, as the clinical features overlap significantly and the scapular region receives innervation from nerve roots (C5-C6) that contribute to the brachial plexus. 1

Understanding the Anatomical Basis

The brachial plexus is formed from ventral rami of C5-T1 nerve roots, passing between the anterior and middle scalene muscles alongside the subclavian artery, then organizing sequentially into roots, trunks, divisions, cords, and terminal branches. 1, 2 The scapular muscles receive innervation from nerves that originate from the upper portions of the brachial plexus, particularly from C5-C6 nerve roots. 3

Key anatomical point: The dorsal scapular nerve, which supplies muscles around the medial scapular border (where your tingling is located), typically arises from the C5 nerve root before the plexus fully forms. 4 This creates diagnostic ambiguity—is the problem at the nerve root level (radiculopathy) or at the plexus level (plexopathy)?

Critical Diagnostic Features That Point to Plexopathy vs. Radiculopathy

The distribution pattern is your most important clinical clue:

• Brachial plexopathy causes symptoms that cross multiple dermatomes and affect multiple peripheral nerve distributions simultaneously in the shoulder and arm. 1, 2
• Cervical radiculopathy typically follows a single dermatome distribution. 1

In your case, the combination of inner scapular tingling (C5-C6 territory) with hand weakness suggests involvement of multiple nerve root levels, which is more consistent with plexopathy than isolated radiculopathy. 1

The Diagnostic Challenge: Overlap Between Conditions

Critical pitfall: The American College of Radiology explicitly warns that clinical diagnosis of plexopathy can be challenging because neurologic signs and symptoms may overlap considerably between radiculopathy and plexopathy. 5 In cases of clinical uncertainty, both cervical spine and brachial plexus imaging may be necessary. 2

Specific Clinical Features to Assess

Look for these distinguishing characteristics:

• Pain pattern: Neuropathic pain crossing multiple peripheral nerve distributions (not confined to one dermatome) favors plexopathy. 1, 2
• Weakness distribution: Weakness in regions innervated by multiple nerves from the plexus (not just one nerve root distribution) indicates plexopathy. 1, 2
• Reflex changes: Flaccid loss of multiple tendon reflexes in the affected limb suggests plexopathy. 1, 2
• Sensory loss: Sensory deficits across multiple nerve distributions rather than a single dermatome. 1, 2

Etiologies to Consider in Your Patient

Given the history of possible cervical spondylosis or trauma, consider:

• Traumatic causes: Compression from hematoma can cause delayed brachial plexopathy (symptoms may not appear for 48 hours after injury). 6
• Cervical spondylosis: Can cause nerve root compression that mimics or coexists with plexopathy. 5
• Inflammatory causes: Parsonage-Turner syndrome (neuralgic amyotrophy) presents with acute pain followed by weakness. 1

Recommended Diagnostic Algorithm

Step 1: Electrodiagnostic studies are essential to confirm clinical diagnosis and differentiate between radiculopathy and plexopathy by showing abnormalities in multiple nerve distributions. 1, 2

Step 2: MRI of the brachial plexus is the gold standard imaging modality, with 81% sensitivity, 91% specificity, and 88% accuracy, providing superior soft-tissue contrast and detailed intraneural anatomy visualization. 5, 1 This provides additional diagnostic information beyond clinical evaluation and electrodiagnostic studies in 45% of patients. 5

Step 3: Consider MRI cervical spine if there is clinical uncertainty about whether the problem is radiculopathy versus plexopathy, as cervical spine pathology is considerably more prevalent. 5 However, do not order cervical spine MRI alone when plexopathy is suspected, as it only evaluates nerve roots within and immediately adjacent to neural foramina, missing the plexus lateral to the foramina. 1

Step 4: CT with IV contrast offers the next highest level of anatomic visualization if MRI is contraindicated. 1, 2

Critical Pitfall to Avoid

Never assume cervical spine imaging alone is sufficient. Cervical spine MRI is inferior to brachial plexus MRI for evaluating plexopathy because it does not directly evaluate the brachial plexus lateral to the neural foramina. 5 CT myelography and CT cervical spine cannot visualize preganglionic nerve roots or fully evaluate the postganglionic plexus. 5, 1

Treatment Implications

Distinguishing between preganglionic (root avulsion) and postganglionic injuries is crucial, as treatment approaches differ significantly. 1, 7 In severe trauma to the lower cervical spine with concomitant brachial plexus lesion, root avulsions must be expected in 83% of cases. 8