What is the diagnosis and treatment for right clavicle (collarbone) shoulder pain that radiates down the arm with associated weakness in the right arm?

Diagnosis and Management of Right Clavicle/Shoulder Pain with Radiating Arm Weakness

Primary Diagnosis

This presentation of clavicular/shoulder pain radiating down the arm with weakness requires urgent evaluation for cervical radiculopathy, brachial plexus pathology, or rotator cuff injury with nerve involvement, rather than isolated clavicular pathology. The radiating pain and weakness pattern suggests neurological compromise that takes priority over localized musculoskeletal issues 1.

Differential Diagnosis to Consider

The key diagnostic considerations include:

• Cervical radiculopathy - Pain radiating from the shoulder down the arm with weakness is a classic presentation that can be mistaken for primary shoulder pathology 1
• Rotator cuff tear with nerve involvement - Can present with pain and weakness, particularly in older patients 1
• Brachial plexus injury or compression - Radiating pain and weakness suggest nerve involvement 2
• Clavicle stress fracture - Can present with severe shoulder and arm pain radiating to the upper extremity, though typically without isolated weakness 2
• Acromioclavicular joint pathology - Can cause referred pain but less commonly causes arm weakness 3

Initial Diagnostic Workup

Immediate Physical Examination Priorities

• Assess for neurological deficits including motor strength testing of specific myotomes (C5-T1), sensory distribution, and deep tendon reflexes to localize nerve root involvement 4
• Palpate the clavicle for tenderness, deformity, or masses that might indicate fracture or other pathology 4
• Perform Spurling's test to evaluate for cervical radiculopathy (neck extension with rotation and axial compression reproducing arm symptoms)
• Test rotator cuff strength specifically with empty can test (supraspinatus), external rotation (infraspinatus), and lift-off test (subscapularis) 1

Initial Imaging Strategy

Standard radiography is the preferred initial study, including at least three views: anteroposterior views in internal and external rotation, plus an axillary or scapula-Y view, performed with the patient upright 4. This effectively demonstrates fractures, dislocations, and shoulder malalignment 4.

Advanced Imaging When Radiographs Are Noncontributory

If initial radiographs are negative but symptoms persist:

• MRI without contrast (rating 7/9) or MR arthrography (rating 9/9) is indicated for suspected soft tissue injuries including rotator cuff tears and labral pathology 4
• Cervical spine MRI should be strongly considered given the radiating pain and weakness pattern, as this presentation can indicate cervical disk disease that mimics shoulder pathology 1
• MRI sections parallel to the long axis of the clavicle may be helpful if clavicular stress fracture is suspected, as standard views can miss this diagnosis 2

Critical Pitfalls to Avoid

• Do not assume isolated shoulder pathology when weakness and radiating pain are present - cervical radiculopathy must be ruled out as it can be mistaken for shoulder impingement or other shoulder processes 1
• Do not delay orthopedic or neurosurgical referral if neurological deficits are present, as this can make stabilization more technically challenging 4
• Do not miss fracture components by failing to obtain orthogonal views, which can lead to underestimation of injury severity 4
• Do not attribute all shoulder pain to common rotator cuff pathology - persistent pain despite appropriate intervention should raise concern for alternative diagnoses including clavicular lesions or cervical pathology 5

ICD-10 Coding

Based on the clinical presentation:

• M25.511 - Pain in right shoulder (primary code for shoulder pain)
• M79.601 - Pain in right arm (for radiating symptoms)
• M62.81 - Muscle weakness (generalized) for the arm weakness
• M25.512 - Pain in right shoulder joint (if joint-specific)
• Consider M54.12 (radiculopathy, cervical region) if cervical radiculopathy is confirmed

Immediate Referral Indications

Immediate referral to orthopedic or spine specialist is mandatory if any of the following are present:

• Significant neurological deficits including progressive weakness 4
• Unstable or significantly displaced fractures on imaging 4
• Shoulder joint instability 4
• Persistent severe pain despite conservative management suggesting pathologic fracture or tumor 5

Treatment Approach Pending Definitive Diagnosis

• Activity limitation and analgesic treatment for suspected stress fracture or soft tissue injury 2
• Avoid aggressive physical therapy until neurological causes are excluded
• Serial examinations to monitor for progression of weakness or development of additional neurological signs