The suprascapular nerve is one of the major nerves in the shoulder. It originates from the C5 and C6 vertebrae in the cervical spine, which is the part of the spine located in the neck. The nerves coming from these vertebrae form what is called the superior trunk, and the suprascapular nerve branches off from it.
After branching off, this nerve then passes under the trapesius muscle and proceeds to the top edge of the scapula bone. At this edge, it passes through the suprascapular notch, which is an indented part of the bone. It travels through some more of the shoulder structure before ultimately branching into the supraspinatus and infraspinatus muscles, causing these muscles to act, or innervating them.
These muscles are responsible for much of the movement of the shoulder. The supraspinatus is responsible for shoulder abduction, the motion that allows a person to clap his hands above his head. The infraspinatus helps a person to rotate the shoulder, in the way that a person putting on a seatbelt does. If the suprascapular nerve becomes compressed or entrapped through injury or because of overuse, either partial or full loss of the use of these muscles — and consequent loss of shoulder motion — can result.
The nerve also extends sensory nerve fibers to the ligamentous and capsule structures of the shoulder joint. Since this is the case, sometimes bursitis and tendinitis symptoms can result, if the nerve becomes damaged. These symptoms are often evident when a person tries to raise his arms above his head or when the person rotates the shoulder joint.
Some common causes of suprascapular nerve injury include a direct blow to the base of the neck or back of the shoulder; repetitive stress injuries from activities, such as tennis and volleyball; and weightlifting or heavy lifting required by a job. Typically, a doctor can diagnose damage to the nerve by looking at the muscles and checking them for atrophy. Depending on the injury, there are a few options available for treatment. Some of these include a suprascapular nerve block, physiotherapy, and surgical suprascapular nerve decompression.
The nerve block is a combination injection of a local anesthetic and steroid into the suprascapular nerve. This is often used to prevent, or control, the pain associated with tendinitis or bursitis. Surgical nerve decompression can be done through the use of endoscopy, with small incisions. It is typically used to relieve pressure on the nerve, if it has become compressed or entrapped due to injury, or possibly because of the presence of a cyst.