What is the best course of action for an adult patient with a history of repetitive strain or trauma to the shoulder, presenting with right shoulder pain, positive empty can and liftoff tests, and now experiencing numbness and tingling to the finger?

Urgent Evaluation for Peripheral Nerve Injury

This patient requires immediate assessment for peripheral nerve injury, specifically brachial plexus or individual nerve involvement (median, ulnar, or radial nerve), as numbness and tingling in the finger represents a neurological complication that supersedes the rotator cuff pathology indicated by the positive empty can and liftoff tests. 1

Immediate Clinical Assessment Required

• Perform detailed neurological examination mapping the exact distribution of numbness and tingling to identify which specific nerve(s) are affected—median nerve involvement causes numbness in thumb, index, middle, and radial half of ring finger; ulnar nerve affects small finger and ulnar half of ring finger; radial nerve affects dorsal first web space 1

• Test for vascular compromise by checking distal pulses, capillary refill, and skin temperature, as the axillary artery can be injured with shoulder trauma, particularly with proximal humeral fractures or dislocations 1

• Document motor function in the affected hand including grip strength, finger abduction/adduction, thumb opposition, and wrist extension to distinguish between pure sensory versus sensorimotor nerve injury 1

Imaging Protocol

Order MRI shoulder without IV contrast as the definitive next imaging study, as this is the American College of Radiology's recommended modality for nonlocalized shoulder pain that can identify rotator cuff tears, labral injuries, and osseous contusions invisible on plain films 2

• If radiographs have not yet been performed, obtain them first with minimum three views (AP in internal rotation, AP in external rotation, and axillary or scapula-Y view) to rule out fracture or dislocation that could be compressing neurovascular structures 3

• If vascular compromise is suspected clinically (absent pulses, cold extremity, expanding hematoma), immediately order CT angiography rather than MRI, as CTA provides optimal spatial and temporal resolution for identifying arterial injuries and can be performed rapidly 1

• Consider MR neurography using 3-T imaging if peripheral nerve injury is strongly suspected, as this can delineate focal nerve discontinuities, neuromas, and musculofascial edema that standard MRI sequences may miss 2

Critical Management Decisions

Refer urgently to orthopedic surgery or hand surgery if any of the following are present: progressive neurological deficit, complete sensory loss in a nerve distribution, motor weakness, or signs of vascular compromise 2

• Do not delay imaging or referral while attempting conservative management, as nerve injuries associated with shoulder trauma can represent brachial plexus injury requiring specialized evaluation 1

• Avoid overhead pulley exercises which are specifically not recommended in shoulder pathology and could worsen nerve compression 1

Common Pitfalls to Avoid

• Do not attribute all symptoms to rotator cuff pathology alone when neurological symptoms are present—the positive empty can and liftoff tests indicate supraspinatus and subscapularis involvement respectively, but these do not explain finger numbness 4

• Do not assume the numbness is simply "referred pain" from shoulder pathology, as true neuropathic pain requires a demonstrable lesion or disease of the somatosensory nervous system and represents a distinct clinical entity 1

• Do not order ultrasound as the primary imaging modality in this scenario, as it has limited usefulness for nonlocalized shoulder pain and cannot adequately assess for nerve injury or intra-articular pathology beyond rotator cuff tears 1, 2