Many potential causes for shoulder pain exist. A pinched nerve causing shoulder pain is distinct in that the source of the pain is not the shoulder at all. The more likely location of the pinched nerve is in the neck. According to a 1993 study published in the "Scandinavian Journal of Primary Care," neck and/or shoulder pain may affect 15 percent of men and 25 percent of women on at least a monthly basis. There are unique signs and symptoms, diagnostic tests, and treatments for pinched nerves that are creating shoulder pain.
Anatomy
The nerves that carry pain impulses from the shoulder and arm travel to and from the spinal cord through small openings between the vertebrae called "intervertebral foramina." It is at or near these small openings where the nerves are most vulnerable to compression or pinching. Just as flipping a switch on a wall can turn on or off a light across a room, pinching a nerve in the neck can cause pain that is felt at points all along the course of the nerve. So a pinched nerve in the neck often causes pain further away in the shoulder.
Causes
Trauma is a frequent cause of a pinched nerve in the neck. When a football player takes a forceful blow to the head and neck, he may experience a "stinger." That is a classic example of a sudden and intense pain in the shoulder and arm resulting from a pinched nerve. A bulging or herniated disc in the neck may also pinch a nerve, as may an arthritic bone spur. Less frequently, a tumor may press on a nerve with similar results.
Symptoms
The pain of a pinched nerve can be pretty intense. The location can vary with positions and activities. It may radiate just to the top of the shoulder or it may go all the way down the arm. Often, in addition to pain, there is some numbness and/or loss of strength in the affected shoulder or arm. If it feels better to raise the arm overhead, this may be a big clue that the pain is from a pinched nerve. Most shoulder injuries are more painful in this position. This sign is actually described in a 1989 article in the "Archives of Physical Medicine and Rehabilitation."
Diagnosis
A knowledgeable clinician will usually try to narrow down the diagnosis with a series of orthopedic physical tests of movement or position. If a pinched nerve is suspected, an imaging test is usually ordered. Sometimes an X-ray is adequate to determine the source of the nerve compression; sometimes a CT scan or an MRI is more helpful. Electromyography, a test that measures the electrical activity of muscles and the nerves that control them, may be helpful in determining the precise location and extent of the nerve compression.
Treatment
The goal of treatment is to restore and maintain adequate space for the affected nerve. In mild or moderate cases, this may be done with traction, physical therapy, chiropractic treatment or other conservative methods. In cases where the compression is severe or when the cause of the compression is not amenable to conservative methods, surgery may be considered.
References
- "Scandinavian Journal of Primary Health Care;" Headache and Neck or Shoulder Pain--Frequent and Disabling Complaints in the General Population; 1993
- Archives of Physical Medicine and Rehabilitation; "The Shoulder Abduction Relief Sign in Cervical Radiculopathy"; A Fast, S Parikh and E Marin; May 1989
