Whiplash injuries of the temporomandibular joint in motor vehicle accidents: Speculations and facts

McKay, Duane C.; Christensen, Larry

doi:10.1046/j.1365-2842.1998.00321.x

Cited by 30 publications

(29 citation statements)

References 72 publications

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“…During slow masticatory depression of the mandible, duration of about 236 ms (Gibbs et al, 1982;Jemt & Olsson, 1984;Karlsson & Carlsson, 1989;Karlsson et al, 1991) and an arbitrary, but probable depressor force of 3 kg, the total impulse of slow depression would be in the order of 3 ×236= 708 kg ms (1560 lb ms). In all cases, the impulses of the mandibular motion of depression are absorbed and dissipated by, primarily, the tissues of the temporomandibular joint (McKay & Christensen, 1998). Over a follow-up period of 12 months, this study found no injury to the temporomandibular joints.…”

Section: Discussionmentioning

confidence: 56%

“…We have previously discussed the tenuous diagnosis of a so-called whiplash injury of the temporomandibular joint, and have shown that the postulated diagnosis and postulated mechanism of injury have no foundation in basic and clinical science (Christensen & McKay, 1997;McKay & Christensen, 1998, 1999. That is to say, if a rapid injurious depression of the mandible were to occur during the first phase of a whiplash manoeuvre of the head and neck (posterior rotation of the head/extension of the neck), the motion would immediately be counteracted by a mandibular elevation, elicited through a stretch reflex in the mandibular elevator muscles (Christensen & McKay, 1997), and by the inability of the rather weak depressor muscles to anchor the mandible in space (McKay & Christensen, 1999).…”

Section: Discussionmentioning

confidence: 99%

“…Applying extrapolation to Hill's equation, Watanabe et al (1991) postulated that maximum opening and closing velocities would be in the order of 0·450 m s − 1 and 0·370 m s − 1 , respectively, and maximum opening and closing forces would be in the order of 30 kg and 35 kg, respectively. However, a theoretical peak depressor force of 30 kg must be in error, simply because it is overlooked that the force is isometric (nil velocity) and the aggregate physiological cross-sectional area of the elevator muscles exceeds that of the depressor muscles by a factor of 10-15 (McKay & Christensen, 1998). Also, depressor and elevator velocities in the order of 0·400 m s − 1 are unlikely to occur in real life where maximum velocities of only about 0·200 m s − 1 have been documented (Widmalm & Hedegard, 1977).…”

Section: Introductionmentioning

confidence: 99%

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Kinematic and kinetic observations on ballistic depression and elevation of the human mandible

Christensen¹,

McKay²

2000

J of Oral Rehabilitation

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To study mandibular motions with respect to time (kinematics) and the forces causing and resulting from these motions (kinetics), four subjects generated rapid depression and elevation of the mandible (displacement of 0.224 m; peak velocity of 0.237 m s(-1) during depression and 0.269 m s(-1) during elevation). The motion of depression (duration of 0.195 s; kinetic energy of 2.072 x 10(-3) J) could be divided into a phase of acceleration (2.742 m s(-2); +/- 0.28 gn) and a phase of deceleration (2.264 m s(-2); - 0.23 gn), and the terminal excess kinetic energy of depression was absorbed and dissipated by, primarily, the temporomandibular joint. Similarly, the ensuing motion of elevation (duration of 0.182 s; kinetic energy of 2.948 x 10(-3) J) could be divided into a phase of acceleration (3.498 m s(-2); + 0.36 gn) and a phase of deceleration (2.931 m s(-2); -0.30 gn), and the terminal excess kinetic energy of elevation was absorbed and dissipated by, primarily, the dentitions and, secondarily, by the temporomandibular joint. Rapid depression of the mandible appeared to be under the central control of a preprogrammed motor command, and ensuing rapid elevation of the mandible appeared to be under the peripheral control of a segmental and/or transcortical reflex. During rapid depression and elevation of the mandible, the anterior suprahyoid, anterior temporalis, and sternocleidomastoid muscles were myoelectrically active 56%, 73%, and 71% of the time, respectively, and myomechanically active 42%, 59%, and 57% of the time, respectively. Over a follow-up period of 12 months, the studied mandibular motions did not cause injury to the dentitions and temporomandibular joint.

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Section: Discussionmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinematic and kinetic observations on ballistic depression and elevation of the human mandible

Christensen¹,

McKay²

2000

J of Oral Rehabilitation

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“…A so-called whiplash injury of the temporomandibular joint (TMJ) is a more than tenuous clinical concept, always postulated to be the result of a traumatic anterior acceleration of the TMJ condyles (anterior hypertranslation/posterior hyperrotation) and, usually, an ensuing traumatic posterior acceleration of the TMJ condyles (posterior hypertranslation/anterior hyperrotation). For reviews of the postulated concept and diagnosis of a TMJ whiplash injury, see Christensen & McKay (1997), Howard et al (1998) and McKay & Christensen (1998).…”

Section: Introductionmentioning

confidence: 99%

Electrognathographic and electromyographic observations on jaw depression during neck extension

McKay¹,

Christensen²

1999

J of Oral Rehabilitation

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Albeit never substantiated through experimental and clinical evidence, the theoretical linchpin of the mechanics of a so-called whiplash injury of the temporomandibular joint (TMJ) is the postulate that a pre-existing depressor force (continual anchoring force), generated by the anterior suprahyoid (SH) muscles, will always act on the mandible and cause traumatic mouth opening (anterior acceleration of the TMJ condyles) when the neck is extended (posterior acceleration of the head). To test aspects of this postulate, six subjects assumed the positions of neutral (0 degrees ), medium (32 degrees ) and maximum (58 degrees ) neck extension while the mandible was in its postural positions of rest and light centric occlusion. By means of surface electromyography, it was shown that the relative contractile activities of the anterior SH muscles never exceeded 7.3% of the contractile activity required to anchor the mandible in a position of maximum depression. By means of electrognathography, it was shown that the maxillary and mandibular incisors were never separated by more than 2.6 mm during neutral, medium, and maximum extension of the neck. In other words, during neck extensions there was no evidence of a continual or induced voluntary or involuntary depressor force that would and could anchor the mandible in a position of traumatic mouth opening. Accordingly, and in agreement with other biophysical and biomedical evidence, it was concluded that there is no foundation for the pseudoscientific speculations and unsubstantiated opinions offered in support of a concept and diagnosis of a so-called TMJ whiplash injury. Additionally, this study found co-activation of cervical flexor muscles and mandibular elevator as well as depressor muscles.

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“…Assuming the emphasis is indeed on establishing functional congruency, what are the biomechanics associated with the process of heterotopic bone moving the mandible out of position? Referring to the age-old question of the relationship between whiplash and TMDs, 33,50,64,70 can bioengineers shed new light on the actual forces experienced in whiplash? More specifically, what is the significance of extension/flexion injuries of the neck and TMJ and the magnitude of condylar acceleration in these instances?…”

Section: Directives From the Clinical Communitymentioning

confidence: 99%

A Call to Action for Bioengineers and Dental Professionals: Directives for the Future of TMJ Bioengineering

2007

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Abstract-The world's first TMJ Bioengineering Conference was held May 25-27, 2006, in Broomfield, Colorado. Presentations were given by 34 invited speakers representing industry, academics, government agencies such as NIH, and private practice, which included surgeons, engineers, biomedical scientists, and patient advocacy leaders. Other attendees included documentary film makers and FDA officials. The impetus for the conference was that the field of TMJ research has been lacking continuity, with no open forum available for surgeons, scientists, and bioengineers to exchange scientific and clinical ideas and identify common goals, strengths, and capabilities. The goal was thus to plant the seeds for establishing a forum for multidisciplinary and interdisciplinary interactions. The collective wisdom and interactions brought about by a melting pot of these diverse individuals has been pooled and is disseminated in this article, which offers specific directives to bioengineers, basic scientists, and medical and dental professionals including oral and maxillofacial surgeons, pain specialists, orthodontists, prosthodontists, endocrinologists, rheumatologists, immunologists, radiologists, neurologists, and orthopaedic surgeons. A primary goal of this article was to attract researchers across a breadth of research areas to lend their expertise to a significant clinical problem with a dire need for new talent. For example, researchers with expertise in finite element modeling will find an extensive list of clinically significant problems. Specific suggestions for TMJ research were presented by the leading organizations for TMJ surgeons and TMJ patients, and further research needs were identified in a series of group discussions. The specific needs identified at the conference and presented here will be essential for those who endeavor to engage in TMJ research, especially in the areas of tissue engineering and biomechanics. Collectively, it is our hope that many of the questions and directives presented here find their way into the proposals of multidisciplinary teams across the world with new and promising approaches to diagnose, prevent and treat TMJ disorders.

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Whiplash injuries of the temporomandibular joint in motor vehicle accidents: Speculations and facts

Cited by 30 publications

References 72 publications

Kinematic and kinetic observations on ballistic depression and elevation of the human mandible

Kinematic and kinetic observations on ballistic depression and elevation of the human mandible

Electrognathographic and electromyographic observations on jaw depression during neck extension

A Call to Action for Bioengineers and Dental Professionals: Directives for the Future of TMJ Bioengineering

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