A 19-year-old volleyball player reports deep posterior shoulder pain and progressive weakness on overhead serve. Examination shows obvious wasting of infraspinatus with weakness of external rotation, while the supraspinatus is bulky and abduction strength is normal. Where is the compressive lesion?

• A Suprascapular notch, beneath the superior transverse scapular ligament
• B Triangular interval
• C Quadrilateral space
• D Spinoglenoid notch, beneath the inferior transverse scapular ligament ✓

Explanation

The suprascapular nerve gives off its branch to supraspinatus before entering the spinoglenoid notch. A ganglion cyst at the spinoglenoid notch therefore compresses only the terminal fibres to infraspinatus, giving isolated wasting and external rotation weakness. Compression at the suprascapular notch, the best distractor, would involve both supraspinatus and infraspinatus, producing abduction weakness as well.

Reference: Moore's Clinically Oriented Anatomy, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.