Last year I developed neck pain for no apparent reason. I didn't injure myself that I'm aware of. This year, I did hurt my shoulder. Now there's a noticeable difference in the way the neck and arm move on that side. Is this coming from the neck or the shoulder?
This is an important question because there may be altered muscle function depending on the etiology (cause) of each problem (neck versus shoulder). A recent study from the University of Iceland may offer some helpful insight.
They compared two groups of patients with neck pain. One group had been involved in a motor vehicle accident (MVA). The second group had neck pain but no history of MVA. There was actually a third (control) group who had no neck pain and no history of MVA. Most of the participants were women. Everyone was right-handed. And the groups were carefully matched by age, size, and activity level.
The main focus of the study was on movement of the scapula (shoulder blade) with arm elevation. We know that the muscles that control shoulder motion and in particular scapular motion can have a direct effect on the neck. Evaluating scapular motion and comparing between neck and shoulder injuries might give some clues about where the pain is coming from.
And comparing these results with results from other studies looking at shoulder pain has provided some interesting clues to what is happening. If scapular motion (and therefore muscle timing, rhythm, and control) is different depending on the etiology (cause) of neck pain, then treatment might vary accordingly.
They found that everyone with neck pain had a different scapular orientation during arm movement compared with normals. This suggests some type of movement impairment that needs to be addressed in treatment. Unless everything moves in proper alignment, uneven pull on the neck from altered dynamic stability of the scapula will cause continued neck pain.
Second, patients with neck pain from a whiplash had similar muscle patterns seen in patients with true shoulder problems (moreso than when compared with neck pain of unknown cause). There was an uneven pull between the muscles of the neck and shoulder contributing to clavicular elevation and scapular tilt.
The authors concluded that identifying patterns of muscle impairment with different types of problems may guide treatment of patients with neck and/or shoulder pain. Getting normal motor function and alignment may be the key to preventing ongoing or recurring neck pain whether the problem originates in the neck or the shoulder.