Understanding whiplash and TMD.

• Author: Moses, Allen J.
• Position: Temporomandibular Disorders, part 2

WHIPLASH refers to the hyperextension/hyperflexion trauma that occurs in automobile accidents. These injuries have long been perplexing cases for physicians, attorneys and claims adjusters. The symptoms, most commonly limited to the soft tissues, do not show up on radiographs, and thus they are very difficult to document and often resistant to treatment. The symptomatology may not appear immediately following the accident, but it may show up days or weeks later, often making the victims seem to be malingers.

Head, neck, back and face pain, limited range of motion of the head and neck, clicking and pain in the temporomandibular joint, anterior head posture, difficulty swallowing, alterations of back and neck posture, vertigo and tinnitus are common symptoms following whiplash trauma.

In the past, treatment consisting of physical therapy, electrotherapy and cervical collars has not been universally successful. In the early 1980s the dental literatue noted the similarity in symptomatology between temporomandibular disorders (TMD) and whiplash. Dentistry helped elicit the intercausality linking the two and pointed out that many victims of whiplash trauma are predisposed to such injury.

With the recognition of the associated temporomandibular disorder and appropriate treatment, the success rate of restoring patients to a pain-free status has significantly improved. The TMD associated with whiplash is diagnosed, documented and treated by the dentist virtually identically to non-traumatic TMD.

Mechanisms of causality

It has been established that there are at least two mechanisms of causality by which accidents involving acceleration/deceleration of the head on the spinal column can cause TMD/whiplash injury.

One causality offered by which cervical trauma could result in TMJ symptoms involves a complex kinematic chain of events beginning with injury to cervical muscles, subsequent myospasm, posterior hyperextension of the head, reflex adaptation of head posture, increasing tension on hyoid musculature, inferior and posterior movement of the mandible, altered muscle accommodation to facilitate occlusal contact, with resultant masticatory muscle bracing followed by spasm.

Spasm of the lateral pteygoid muscle specifically is important in this scenario because it attaches to the temporomandibular disk and its shortening would result in disk displacement and clicking. This mechanism of cervical trauma causing TMD further explains the delayed time frame from trauma to pain. It could take from days...