What is the most likely diagnosis and recommended management for a pinched nerve under the right shoulder blade causing pain radiating down the right arm to the hand?

Cervical Radiculopathy: Most Likely Diagnosis

The most likely diagnosis is cervical radiculopathy from nerve root compression at C6-C7 or C7-C8, causing referred pain from the scapular region radiating down the arm to the hand. 1, 2

Why Cervical Spine Pathology, Not Primary Shoulder Disease

• Pain originating under the shoulder blade (scapular region) with radiation down the entire arm to the hand is the classic presentation of cervical nerve root compression, not rotator cuff pathology. 3, 1
• Rotator cuff disease typically causes anterior or anterolateral shoulder pain that does not radiate beyond the deltoid insertion; pain extending to the hand indicates nerve involvement. 3, 1
• Cervical radiculopathy most commonly results from herniated discs or osteophytes compressing nerve roots, producing neuropathic pain that radiates in a dermatomal distribution. 1, 2
• The scapular region is a common referral site for cervical spine pathology, particularly when nerve roots are irritated without obvious radiculopathy symptoms initially. 3, 4

Critical Diagnostic Steps

Document the exact radiation pattern to determine which cervical nerve root is involved:

• C6 radiculopathy: pain radiating to thumb and index finger with biceps reflex diminished 2, 5
• C7 radiculopathy: pain radiating to middle finger with triceps reflex diminished (most common neurologic finding) 2, 5
• C8 radiculopathy: pain radiating to ring and small fingers 2, 6

Perform specific provocative tests:

• Spurling test (neck extension with rotation and axial compression toward affected side): reproduces radicular pain if positive 2, 6
• Shoulder abduction test (relief of symptoms when arm is abducted and hand placed on head): suggests nerve root compression 2
• Upper limb tension test: stretches nerve roots and reproduces symptoms 2

Assess for motor, sensory, and reflex deficits:

• Test grip strength, wrist extension, elbow flexion/extension in specific myotomal distributions 2, 6
• Check sensation in dermatomal patterns (C6: thumb/index; C7: middle finger; C8: ring/small fingers) 2, 6
• Diminished triceps reflex is the most common neurologic finding in cervical radiculopathy 2

Imaging Protocol

Start with cervical spine MRI without contrast as the preferred initial advanced imaging when clinical examination supports radiculopathy, as it directly visualizes disc herniations, osteophytes, and nerve root compression. 1, 2

• Plain radiographs of the cervical spine may be obtained first only to assess for gross structural abnormalities or alignment issues, though they cannot visualize disc herniations or nerve roots. 1
• MRI should not be delayed if red flags are present (progressive weakness, myelopathy signs, trauma history). 1, 2
• Electrodiagnostic testing (EMG/nerve conduction studies) has sensitivity over 80% and specificity of 95% for confirming nerve compression and localizing the level, but is only needed if imaging is negative or equivocal, or if peripheral neuropathy is a likely alternate diagnosis. 1, 2

Do not order shoulder MRI unless physical examination specifically suggests concurrent rotator cuff pathology with positive impingement signs (Hawkins, Neer tests) and pain isolated to shoulder movements without radiation. 1

Initial Management Algorithm

Reassure the patient that most cases resolve regardless of treatment type – the overall prognosis is favorable with focused nonoperative care. 2, 5

Immediate conservative management (first 4-6 weeks):

1. Activity modification: Complete avoidance of aggravating neck movements and overhead activities until pain-free 3, 2

2. Physical therapy involving:

   • Cervical strengthening and stretching exercises 2, 5
   • Cervical traction may temporarily decompress nerve impingement 5
   • Avoid overhead pulley exercises which can worsen symptoms 3

3. Pharmacologic management:

   • NSAIDs for pain and inflammation 2, 5
   • Muscle relaxants for associated muscle spasm 2, 5
   • Neuropathic pain agents (pregabalin 300-600 mg daily in divided doses, gabapentin, or duloxetine) if neuropathic features are prominent 1

4. Short-term cervical collar for immobilization (limited duration to prevent deconditioning) 5

Escalation if symptoms persist after 4-6 weeks:

• Epidural steroid injections may be helpful but carry higher risks of serious complications 2
• Selective nerve root blocks can target specific nerve root pain 5

Surgical referral indications:

• Red flag symptoms (progressive weakness, myelopathy, bowel/bladder dysfunction) 2, 6
• Persistent debilitating symptoms after 4-6 weeks of adequate conservative treatment 2, 6
• Significant progressive motor weakness 6
• MRI-confirmed pathology amenable to surgical decompression 2

Critical Pitfalls to Avoid

• Do not assume this is "muscle tension" or "muscle spasm" without ruling out structural cervical spine pathology – imaging should not be delayed if clinical suspicion is high. 1
• Do not misinterpret cervical radiculopathy pain as primary shoulder impingement – the radiation pattern to the hand is the key distinguishing feature. 1
• Do not order shoulder imaging first when the clinical presentation clearly suggests cervical origin (scapular pain radiating to hand). 1
• Cervical spine narrowing can cause shoulder pain even without obvious radiculopathy symptoms initially, so maintain high clinical suspicion. 4