Over the past 10 years, the way whiplash injuries is classified has changed. Chronic tenderness, pain, and stiffness from a whiplash injury is now labeled as a whiplash associated disorder (WAS). There are four grades of WAD based on severity of symptoms.
With Grade I WAD, there are painful symptoms but no objective physical signs of pathology. Patients with Grade II whiplash have painful symptoms and musculoskeletal signs of involvement (e.g., decreased motion). Grade III means there are neurologic changes such as muscle weakness, numbness, or tingling. And Grade IV is used to describe patients with a bone fracture or dislocation.
When examining the neck, the physician must differentiate between upper cervical spine problems and lower cervical spine. Symptoms of whiplash must be distinguished from fibromyalgia and chronic cervical syndrome.
In this study, the authors showed that trigger points of specific muscles in the upper neck point to WAD. Trigger points of the lower neck and upper shoulder are more common in people with fibromyalgia, nontraumatic chronic cervical syndrome, depression, and even in healthy subjects. All five diagnoses were represented among the subjects chosen for participation in this study.
A careful examination of the upper and lower cervical spine was done on each participant. Trigger points of six specific muscles were identified. The six muscles included the semispinalis capitis, trapezius pars descendens, levator scapulae, scalenus medius, sternocleidomastoid, and masseter.
These particular muscles were chosen for testing based on the fact that they are often affected after a whiplash injury. They are all easy to find and palpate. Each one has a specific pattern of referred pain to the head, face, neck, and arms. A physical therapist trained in trigger point exam and manual diagnosis performed all of the exams.
Any signs of tenderness, taut bands, referred pain, or nodules in the muscle belly were reported. The presence of three of these four criteria was judged as a positive trigger point. Other tests were also performed for neck range of motion, posture, and shape and motion of the spinal column.
The authors say they were expecting to see a higher number of trigger points in the semispinalis capitis and masseter muscles in the whiplash group. Results for the whiplash group were compared with the other groups.
Patients with whiplash do show a different distribution of muscle (trigger point) involvement. In particular, the upper neck muscle (semispinalis capitis) was affected in whiplash more than lower neck and shoulder muscles. This is consistent with findings from other studies that show injury at the C1-C2 facet joints after whiplash. The semispinalis attaches at the base of the skull just above C1-C2.
There was no difference in the masseter muscle response among the various groups. This result differs from previous studies that suggest a significant involvement of the masseter muscle in whiplash associated disorders.
Other findings included similar trigger points in other muscles in whiplash, fibromyalgia, and chronic cervical syndrome. Fibromyalgia patients who usually have tender points did have as many trigger points as patients with whiplash and chronic cervical syndrome. For healthy subjects (the control group) and patients with depression, the trapezius muscle was affected most often.
The information gained from this study will help physical therapists and physicians treating patients with WAD. Focus on the muscles of the upper cervical spine (especially semispinalis capitis) may help patients with this condition.