A group of physical therapists from the University of Iceland posed the question, Does neck pain from shoulder problems differ from neck pain associated with whiplash injuries? This is an important question when working with patients who may have altered muscle function depending on the etiology (cause) of their neck pain.
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.
Comparisons were made by measuring pain intensity and function versus disability. A special tool called the Neck Disability Index (NDI) was used to measure function. This survey includes questions about personal care, reading, lifting objects, working, driving, sleeping, concentration, headaches, and recreation.
But the main focus of interest 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 among the three groups might give some clues about the best way to treat neck pain.
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. In order to examine scapular motion in relation to the neck and arm, each participant wore a special set of sensors. Three sensors were placed: one on the clavicle (collar bone), one on the acromion (part of the scapula), and one just above the elbow.
The subjects were asked to raise the arm over head three times. Data on the movement pattern was sent to a computer for analysis. With each position of the arm, the position of the scapula was recorded. Using this method of measuring scapular orientation during arm movement, they found a general pattern that was the same for all three groups.
The pattern was described as clavicular elevation and retraction with arm elevation. At the same time, the scapula rotated in an upward direction. The scapula rotated inwardly during the first 90 degrees of arm motion, then rotated externally as the arm moved from 90 to 120 degrees.
There were some differences in movement in the group with neck pain from a whiplash-associated disorder (WAD). The clavicle lifted up higher when the arm was elevated (raised) 90 degrees compared with the other groups. Scapular posterior tilt was decreased in the WAD group compared with the other two groups.
The WAD group also had less clavicular retraction on the side of their dominant hand compared to the other (nondominant) side. There was no difference in movement patterns from side-to-side in the normal, healthy (control) group.
What does all this mean really? Well, several things: first, 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 whiplash-associated disorder (WAD) have similar muscle patterns as seen in patients with true shoulder problems (moreso than when compared with neck pain of unknown cause).
There is an uneven pull between the muscles of the neck and shoulder contributing to clavicular elevation and scapular tilt. Altered movement patterns is an area physical therapists excel in treating. Knowing which muscles contract at greater intensity for longer periods of time than normal helps direct treatment.
Other studies have shown that neck pain might be part of the reason why there is altered activity in the scapular muscles. It’s not clear if the altered muscle activity is to compensate for muscles that aren’t working or to prevent painful muscles from contracting and causing further pain. This is an area for further study.
The authors concluded that identifying patterns of muscle impairment with different types of neck problems (e.g., post-whiplash versus unknown cause) may guide physical therapists when treating patients with neck pain. Getting normal motor function and alignment may be the key to preventing ongoing or recurring neck pain whatever the cause.