Shoulder injuries after car crashes are a problem recognized in the medical literature. Studies have shown that shoulder pain can be complex; it can originate in the cervical spine, it can arise from direct trauma to the shoulder, and it can develop from long-term muscular tension.

These various sources of shoulder pain can make diagnosis challenging. A new study from the UK investigated the issue of shoulder pain in auto injury patients in an attempt to pinpoint the most common causes of this problem.

The authors studied 220 patients who had come to them for a medico-legal evaluation after a whiplash injury. 202 of these (92%) had been in an automobile collision, and 129 (64%) had been in a rear-end collision.

The study made some interesting general discoveries about whiplash injuries:

As for shoulder injuries:

Of the patients with subacromial impingement:

There were some indications from this study that impingement injuries occur from direct impact to the shoulder. 83% of the impingement patients experienced the condition on their seatbelt shoulder. “Moreover all 11 patients had developed their symptoms early and between 1 and 7 days after the injury, further supporting direct trauma as an underlying cause.” The other two patients with pain on the non-seatbelt shoulder both had bruising in the area of the painful shoulder immediately after the crash.

The study found that there is a serious problem in properly diagnosing these patients:

“All patients had been seen by their general practitioner but only one had been referred for specialist treatment. 3/11 (27%) patients had had their subacromial impingement diagnosed prior to the medicolegal report. From the three patients who were diagnosed prior to the report, only one was diagnosed in the primary care sector, by a physiotherapist who was delivering the ‘neck’ therapy. The remainder had their diagnosis made at the time of our report and subsequently advised to seek further medial assessment. Mean time to diagnosis was 8.8 months.”

This study shows us that shoulder pain is found in about 1 in 4 whiplash patients. About 9% of whiplash patients may have subacromial impingement that may be difficult to diagnose.

Because of the complexity of shoulder pain after an auto collision, a careful evaluation is necessary to assure a proper diagnosis.

Abbassian A, Giddins GE. Subacromial impingement in patients with whiplash injury to the cervical spine.