[Cystic compression of the suprascapular nerve. Value of imaging. Apropos of 6 cases and review of the literature].

Six cases of suprascapular nerve entrapment by a ganglion cyst within the spinoglenoid notch or developed from the glenoid labrum are reported. Causes of injury or entrapment of the suprascapular nerve are described including traction or kinking of the nerve, trauma, repetitive exercise, or compression by ganglion cyst. The patients had non specific pain, weakness, and atrophy of the spinatus musculature. Electromyography showed evidence of denervation atrophy. Patients had plain radiographs, arthrography, CT-arthrography, magnetic resonance imaging (MRI) and MR-arthrography. Masses that caused suprascapular nerve entrapment were well localized and characterized wit magnetic resonance imaging, reflecting the superior soft-tissue contrast of this modality. In addition, MRI may demonstrate atrophy of the spinatus muscles. MR-arthrography allows to visualize lesions of the glenoid labrum and in some cases, demonstrates cysts filling.