Korean J Leg Med.  2013 May;37(2):66-72. 10.7580/kjlm.2013.37.2.66.

A Study of Impact on Head and Neck Using Human Volunteer Low-Speed Rear Impact Tests

• Park SJ
• Yang K
• Lee HS
• Park NK
• Hong SW
• Yoo JH
• Kim H

• KMID: 1433181
• DOI: http://doi.org/10.7580/kjlm.2013.37.2.66

Abstract

Whiplash injury in low-speed traffic accidents are not objectively verified by medical equipment, thereby creating scope for misuse, which has resulted in huge social losses worldwide. The aim of this study was to examine the influence of low-speed vehicular rear-impact collisions on middle-aged men, and to analyze the head and neck injury criteria for the symptomatic human volunteers. Data was examined from the results of 50 dynamic sled tests, originally performed by Hong et al. (2012). In the previous tests, 50 men aged 30~50 years were exposed to an impulse equivalent to a bumper-to-bumper rear collision under medical supervision, and no resulting whiplash injury was identified. In this study, for 6 subjects who experienced dull aches over their bodies, head injury criteria (HIC15) and neck injury criteria (N(km)) were calculated according to the accelerations, forces, and moments at the occipital condyle measured by motion capture system. Although there were no changes in magnetic resonance imaging findings in all subjects at the pre-/post-test orthopedic examination, 6 subjects revealed mild aches around the shoulder, back, or lumbar area, and their symptoms disappeared within 2 days. The head and neck injury criteria, HIC15 (3.086 +/- 2.942) and N(km) (0.077 +/- 0.064) were obtained, and the maximum HIC15 and N(km) were found to be significantly lower than the critical injury assessment reference values (HIC15: 700, N(km): 0.3). Moreover, even though 2 subjects were exposed to the same level of change of velocity (7.9 km/h), each N(km) was significantly different (0.179, 0.057). One can therefore conclude that N(km) can vary according to voluntary movements in the human subject.

Keyword

Whiplash injuries; Human experimentation; Automobiles; Traffic accidents

MeSH Terms

Acceleration
Accidents, Traffic
Aged
Automobiles
Craniocerebral Trauma
Head
Human Experimentation
Humans
Magnetic Resonance Imaging
Male
Neck
Neck Injuries
Organization and Administration
Orthopedics
Reference Values
Shoulder
Whiplash Injuries

Figure

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  Fig. 1. Schematic diagrams of grading system of cervical canal stenosis in sagittal scans of cervical spines. According to this scheme, MRIs of human subjects were classified.

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  Fig. 2. Examples of human volunteers'MRI grades. Grade 1 denotes obliteration of more than 50% of subarachnoid space without any sign of cord deformity. Grade 2 denotes central canal stenosis with spinal cord deformity. a) Grade 1 b) Grade 2 c) Grade 3

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  Fig. 3. Movement of a human volunteer (No. 44) at 7.9 ㎞/h of change of velocity. Momentarily, human subject experienced extension and then flexion with 200 ms. Appropriate usage of a headrest can prevent hyper-extension.

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  Fig. 4. Comparison of neck injury criteria. Nkm has no unit because of normalization by critical values of shear force and bending moment.

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