Suprascapular Neuropathy

Suprascapular neuropathy is compression or traction of the suprascapular nerve along its course over the scapula, producing posterior shoulder pain and weakness of external rotation and/or abduction.

Why the notch determines the deficit:

• The motor branches to supraspinatus leave the nerve at or proximal to the suprascapular notch.
• The branches to infraspinatus are given off after the nerve rounds the spinoglenoid notch.
• Therefore a suprascapular notch lesion weakens both muscles, while a spinoglenoid notch lesion weakens infraspinatus only (supraspinatus is spared).

Mechanisms of injury:

1. Compression - a paralabral cyst, ossified/hypertrophied transverse scapular ligament, tumour, or distended veins narrow the notch.
2. Traction - repetitive overhead motion stretches the nerve over a fixed point; the "sling effect" of the spinoglenoid ligament tethers the nerve during cross-body adduction and internal rotation. A large retracted cuff tear can also pull on the nerve medially.
3. A deep, narrow (U-shaped) suprascapular notch crowds the nerve and is associated with a higher entrapment risk.

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Early diagnosis matters: once the infraspinatus undergoes chronic fatty infiltration, strength may not fully recover even after successful decompression.

Other open questions: whether traction neuropathy from a retracted cuff tear needs any direct nerve treatment; the threshold for operating on painless wasting in a high-level athlete; and the lack of a unified outcome metric across small surgical series.

Global Epidemiology

• An uncommon but under-recognised cause of shoulder pain, estimated at roughly 2% of chronic shoulder pain (PMID 25454727).
• Compressive neuropathy is highly prevalent among overhead athletes, but most have no clinically relevant deficit (PMID 32732653).
• Isolated infraspinatus wasting is well described in elite volleyball and other overhead sports, frequently in the dominant arm (PMID 16035699, PMID 29364045).

Side-by-Side Guidance

Across regions the convergent position is that diagnosis rests on EMG/NCS plus MRI, that most cases are managed non-operatively, and that surgery - now predominantly arthroscopic - is reserved for a discrete compressive lesion or refractory symptoms.

Registry & Outcome Notes

• No dedicated international registry exists; evidence rests on RCTs (PMID 34156877), meta-analysis (PMID 35833960), and surgical case series (PMID 33091550, PMID 17210425).
• Arthroscopic decompression series report significant functional improvement and, in the absence of major concomitant pathology, no complications or revisions at medium-term follow-up (PMID 33091550).

High- vs Limited-Resource Practice

• High-resource: routine EMG/NCS, MRI for cyst and labral tear, ultrasound-guided block/aspiration, arthroscopic decompression.
• Limited-resource: clinical pattern recognition and a diagnostic suprascapular nerve block guide management; open decompression under regional anaesthesia remains effective where arthroscopy is unavailable.

Documentation & Consent (universal)

• Record the weakness pattern (supraspinatus vs infraspinatus) and visible wasting at each visit.
• When a cyst is present, document the feeding labral tear and the plan to address it.
• Consent for decompression should include incomplete strength recovery if chronic atrophy exists, cyst recurrence if the labrum is untreated, and risk to the suprascapular nerve and artery.