The suprascapular nerve along the back of the shoulder passes from the neck down the arm and through an opening (notch) along the top of the scapula (shoulder blade). Then it continues down the back of the scapula where it ends. It is mostly a motor nerve, which means it controls some of the actions of the shoulder. Two muscles that are supplied by this nerve are the infraspinatus andsupraspinatus. They make up two of the four muscles of the shoulder rotator cuff. Their actions are shoulder abduction (moving the arm away from the body) and external (outward) rotation of the arm.
Suprascapular neuropathy can be difficult to diagnose. X-rays may be needed to look for fractures, unusual notch formation, and position of the humeral head in the shoulder socket as an indication of the integrity of the rotator cuff muscles. MRIs show the presence of any masses (tumors, cysts) and condition of the soft tissues (labrum, rotator cuff, muscle atrophy). An MRI can even show the nerve pathway and any areas of restriction. Special tests such as nerve conduction studies, electromyography (electrical study of muscle function), and injection of the notch can help pinpoint the location of nerve entrapment.
All of these tests are important because accurate and effective treatment depends on a correct diagnosis. You don’t want to have surgery if you don’t need it. On the other hand, a delay in surgical correction can result in permanent nerve damage — and you don’t want that either! It sounds like your surgeon is being very thorough and careful.
Be patient with the process. This is an unusual problem that doesn’t always show up with classic signs and symptoms. And even when the problem is identified, the cause of the problem isn’t always clear. Suprascapular nerve entrapment can be caused by a wide range of things from overuse to trauma to cyst to tumor or fracture. Once that gets all sorted out, you’ll be well on your way to a treatment that will hopefully restore your full mobility and function.