COMPRESSION OF THE SUPRAESCAPULAR NERVE
The suprascapular nerve is a nerve that comes from the brachial plexus and innervates the supraspinatus and infraspinatus muscles, in addition to conferring sensitivity to the posterosuperior capsule and the acromioclavicular joint.
This nerve crosses 2 gorges where it can be compressed.
First, the notch of the scapula, where it usually passes under the transverse ligament of the notch, as can be seen in illustration 1.

Second, the nerve runs to the infraspinatus muscle that is most posterior and can be compressed in the spinoglenoid notch.
Etiology:
The etiology may be due to a compromise of space in the notch as an ossification of the transverse ligament or even of idiopathic cause.
Diagnosis:
This nerve tends to give a clinical characteristic of lancinating pain and in many cases it is accompanied by loss of strength and atrophy of the supra and infraspinosa fosae in the most evolved cases.
This nerve can be evaluated by an electromyogram (EMG) compared to the healthy contralateral limb.
Treatment:
And, if necessary and after being evaluated by the Physician, both types of compression can be treated arthroscopically, in both cases being carried out a release of the cause that motivates the compression.

Illustration 2. Release of the suprascapular nerve at the level of the notch of the scapula, sectioning the transverse ligament arthroscopically.