Shoulder Pain and the Suprascapular Nerve
An often overlooked cause of shoulder pain is compression of the suprascapular nerve. Nerves conduct signals from the brain to receptors and vice versa. This means some nerves are responsible for sensation, and some for controlling muscles. Many nerves do both and are called mixed nerves. The suprascapular is a mixed nerve.
The suprascapular nerve runs over the back of the shoulder and passes under two tunnels in the scapula.
It has an upper and lower branch and its role is to innervate two of the rotator cuff muscles (supraspinatus and infraspinatus), and for the sensation over the top of the shoulder and into the back of the shoulder. Symptoms of suprascapular nerve entrapment symptoms follow that exact pattern. Patients will exhibit weakness in shoulder abduction and external rotation, will have pain or numbness in that area, and atrophy in the supraspinatus and infraspinatus.
Dysfunction of the suprascapular nerve can happen due to both compression or traction. Compression may be due to something taking up space where the nerve courses, such as a cyst. Traction may be caused by repetitive overhead activity (Freehill et al, 2012). Sports such as volleyball, baseball, and kayaking are common culprits. Labral tears in these sports are common, and there is a correlation between labral tears, and paraglenoid cyst formation (Mahjoub et al, 2018). Wearing a heavy backpack or carrying a heavy purse can also cause compression of the nerve.
Because this shoulder problem is relatively rare and less known than shoulder impingement, if is often misdiagnosed. If you are having persistent pain and nothing seems to be helping, perhaps this condition has been overlooked. As always, it’s best to have it properly diagnosed first, and conservative therapy may alleviate the symptoms through activity modification. Surgical decompression is successful and minimally invasive if conservative rehab does not help.
Freehill, M. T., Shi, L. L., Tompson, J. D., & Warner, J. J. P. (2012). Suprascapular Neuropathy: Diagnosis and Management. The Physician and Sportsmedicine, 40(1), 72–83. doi: 10.3810/psm.2012.02.1953
A Rare Cause of Compression of the Suprascapular Nerve: The Paraglenoid Cyst. (2018, November 5). Retrieved from http://www.jocr.co.in/wp/2018/09/10/2250-0685-1202-fulltext/.