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One of the leading causes of death and disability among young children is motor vehicle accidents. Although current child restraint systems (car seats) have significantly reduced mortality and morbidity, deaths and injuries still occur. Since it is not possible to correlate human child injury potential with the biomechanical devices used for high level impact testing using experimental methods, the acquisition and analysis of specific child injury data identifiable with real world automobile crashes is critical for input to biomechanical research, anthropometric test device (ATD) development and safety standard revisions. The purpose of this study was to analyze vehicular-related trauma that had occurred to children in known crash environments based on accident configuration and car seat design.

The automotive safety community has grown increasingly aware of the societal costs of injury impairment and disability resulting from automobile accidents. A significant portion of this impairment can be attributed to lower extremity trauma. An accident data study was conducted to determine lower extremity injury frequencies and mechanisms for restrained front-seat occupants in frontal collisions. A query of the 1988-1990 NASS (National Accident Sampling System) data provided information on pelvis, femur, knee, leg, and ankle and foot injuries. Age, gender, seating position, and delta-V were examined for their effect on the data. Lower extremity injury data were compared with injury data of similar severity (AIS ≥ 2) for the head, chest, thorax, and abdomen. The NASS data was supplemented with injury impairment information which, combined with anthropomorphic and biomechanical data, provides a prioritization scheme for the design of dummy lower extremities and instrumentation.

Lower limb injuries among motor vehicle occupants are relatively common and are one of the principle causes of permanent disability. The author has reviewed the current literature and his own experience as an orthopaedic surgeon and research accident investigator concerning lower limb injuries among motor vehicle occupants. An unreported series of knee, thigh, hip, pelvis injuries with indepth accident investigation is reported. Incidence rates for specific injury diagnoses are not available. Gross tabulations reveal that lower limb injury is second only to head injury in frequency among injured motor vehicle occupants. Lower limb injuries are possibly the commonest cause of permanent disability and impairment resulting from motor vehicle accidents.

The FMVSS were established to provide the public with uniform safety equipment and design standards based on sound research. Ongoing evaluation is essential to maintain the effectiveness and safety of FMVSS and to ensure that current technology is incorporated in standards development. Serious injury (AIS 3 or greater) reporting by NASS should be upgraded to facilitate standards evaluation and development. Although cost effectiveness is a mandated criteria for standards evaluation, the protection of human life and limb must remain the principle criteria for measuring effectiveness. A citizen's advisory panel, similar to the NMVSAC should be established to assist NHTSA in establishing priorities for standards evaluation, development and promulgation.

The purpose of this paper is to describe a combination of state-of-the-art detailed accident investigation procedures, computerized vehicle crash and occupant modeling, and biomechanical analysis of human injury causation into a method for obtaining enhanced biomechanical data from car crashes. Four accident cases, out of eighteen investigated, were selected for detailed reconstruction. Three were frontal impacts while the fourth was lateral. The CRASH II and MVMA 2-D analytical models were used in the reconstruction process. Occupant motions, force interactions with vehicle components, accelerations on the various body segments, and much other information was produced in the simulation process and is reported in this paper along with scene and injury data from the accidents.

A test series using 12 unembalmed cadavers was conducted to investigate factors affecting the creation of cervical spine damage due to impact to the top of the head. The test subjects were instrumented to measure head, T8 thoracic spine, and sternum acceleration responses. Photographic targets on the head and torso allowed analysis of impact motions from high-speed movies. The stationary test subject was struck by a guided, moving impactor mass of 56 Kg at 4.6-5.6 m/s. The impactor striking surface consisted of a biaxial load cell with padding to vary the contact force-time characteristics of the head/impactor. The orientation of the head, cervical spine, and torso was adjusted relative to the impactor axis to investigate the effect of spinal configurations on the damage patterns. Load and acceleration data are presented as functions of time and as functions of frequency in the form of mechanical impedance.

Selected side-impact cases from the National Crash Severity Study (NCSS) were studied to determine similarities and differences between actual crashes and laboratory (sled) crash tests. Sled tests simulating side impact have been conducted almost exclusively at a 90° impact angle, so the NCSS cases analyzed were those with a near-side occupant and a reported 3 o'clock or 9 o'clock impact vector. Of the 91 cases studied, 51 were judged comparable to the laboratory situation. The remainder generally involved cars struck at a point remote from the passenger compartment, and often involved considerable rotation of the vehicle. Injuries for the 51 cases were tabulated by crash severity (Delta V) and were judged to be quite similar to those observed in laboratory (sled) tests at a slightly higher Delta V. Brief notes are appended concerning each of the reviewed cases.

Because of its flexibility and structure, the cervical spine is disposed to various mechanisms of injury: although not so common as injuries caused by head impacts, cervical fractures and/or fracture-dislocations have been reported without direct impact to the head. Some cervical injuries reported have been sustained by wearers of lap and shoulder belts in auto accidents; however, we do not consider belt use a potential hazard because ample evidence has accrued in the medical and engineering literature to document general injury and fatality reduction by use of seatbelts. We believe that in many instances occupants would be more seriously injured or killed were belts not worn. The present paper reviews reports of cervical injuries without head impact found in the literature and case histories of such injuries from the Highway Safety Research Institute of The University of Michigan, as well as experimental studies in animals, cadavers, and volunteer subjects.

In that the neck has a wide range of movements--flexion, extension, lateral bending and rotation, there is a large variety of types of neck fractures and fracture-dislocations. This paper describes these various fractures and dislocations emphasizing the mechanisms as determined from clinical experience and potential, neurological damage. Fractures and fracture-dislocations with and without spinal cord involvement have been extensively described in the medical literature. This paper will give a brief overview of some of the types of fractures, as well as the mechanisms involved in these injuries. For more detailed descriptions, the reader is encouraged to review the articles in the list of suggested readings found in this symposium proceedings.

Whiplash is a poorly defined term including ligamentous and muscle strains, hematomas, disc injuries, and less frequently, brain, eye and ear injuries. Diagnosis is difficult because clinical signs and Xrays, electromyography and electroencephalography findings are few. Protection and rest will cure most patients within a year but approximately 2/5th of patients have permanent symptoms and disability. Rear-end impact accidents cause the head and neck to hyperextend over the seat back. Whiplash occurs in 38% of exposed occupants. Head rests give protection but differential rebound may occur producing injurious hyperextension and whiplash. The larynx, trachea and esophagus, in front of the spine, are injured by impact against the dash or steering wheel. Airway obstruction may occur and cause death if not restored quickly. Permanent disability can occur because of scarring and partial airway or esophageal obstruction or vocal cord damage.

This paper presents an analysis of 67 neck injuries incurred in diving and sliding accidents in swimming pools. The accidents were investigated to establish the appropriate medical and mechanical factors involved. A mathematical model was developed to allow the prediction of the trajectory and velocity of the subjects prior to their injury. Nine of the accidents were selected for real life simulation. The simulation included the selection of test subjects of similar physical build to the accident victims who then performed the maneuvers leading to the injury, but in deeper water. High speed movies (200 frames per second) were taken, above and below the water, to measure the motion. A frame by frame analysis provided data to determine the trajectory and velocity profiles of the test subject. The maneuvers studied included diving from the pool edge, diving from various board types and sliding down various sliding board configurations.

The anatomy of the major structures of the neck are presented including the anterior throat structures and the components of the cervical spine and associated structures. Basic neck movements and generalized muscle actions are described. Anatomical relationships of the bones, ligaments, muscles and joints of the cervical spine are emphasized as a foundation for a clear understanding of the structural elements involved in neck fractures and dislocations.

Lap-shoulder belt effectiveness has been indicated by many authors, however there is minimal information on the more severe injuries to lap-shoulder belted car occupants. This paper presents details of 15 lap-shoulder belted occupants in frontal collisions and 24 lap-shoulder belted occupants in side impact collisions. Case descriptions of these crashes are presented, each including vehicle, environmental and injury details.

Injuries to the lower torso (abdomen, pelvis, and lumbar spine) were studied in front seat, lap-belted, outboard occupants involved in frontal crashes. The data indicate that the “no injury” category is increased by 50% in belt users over unbelted occupants. Of injured lap-belted occupants, only one in five was injured in the lower torso area. Of these injuries, 7 out of 10 were rated as minor. Belts reduce the occurrence of serious injuries in all lower torso regions except the lumbar area. The more serious injuries occur at impact speeds of over 30 mph. Only 5% of the injured lap-belted occupants had critical to life-threatening injuries in the lower torso area. The angle of the seat belt does not appear to be related to lower torso injury severity.

The basic physical mechanisms underlying recent experimentally observed anomalous behavior in the impact performance of safety helmets evaluated with soft (human-like) and hard (magnesium alloy) headform surrogates are qualitatively and quantitatively explained in this paper. The principal and physical mechanisms brought to light in the headform surrogate investigation are directly applicable to the utilization of other forms of surrogates (head -neck, thorax, whole body). In particular the results raise a serious question as to the validity of using non-human responding surrogates, with human generated injury tolerance data, for the purpose of assessing safety system performance. The implications of the results are that good crash-impact protective devices (helmets, restraints, etc.) could be penalized and, equally important, less safe crash-impact protective system designs could result from improper assessment of safety system performance.

In that restraint systems can be viewed as medicines for the prevention of injury or death, some pharmacological approaches to the occupant restraint discussions are presented. Traffic morbidity and mortality are presented as endemic disease processes and pharmacological countermeasures in terms of testing dose rates, LD 50, side effects, informed consent and multiple drug usage, and federal drug approval are described.

All of the rear-end impact accidents occurring in the city of Rochester, New York, in a three-month period were surveyed by tabulation of the police accident reports. Special police information forms, telephone interviews, and mail questionnaires were used for further data acquisition. Vehicle photographs and medical examinations were conducted for approximately every 20th vehicle. During the data collection period, 691 rear-end impacts occurred. Although a computer program revealed 1371 accidents, defects in the program accounted for the large difference. Whiplash injury frequency based on telephone interview and mail questionnaire data obtained one to seven days after the accident revealed a whiplash injury frequency of 38%, which was approximately twice that determined by on-scene police investigators. Head restraints reduced whiplash frequency by 14% and fixed head restraints appeared to be more effective.

The Abbreviated Injury Scale (AIS) introduced in January 1968 has been widely used by the Medical Engineering Accident Investigation Teams of the NHTSA, by the General Motors ADAP, by the NATO Country Teams in Europe, and by the AMA Physician-Police Teams. The experience and problems involved in use of the AIS are reviewed. An extended and revised AIS has been developed. Validation studies revealed better than 80% accuracy by multiple users. The Comprehensive Research Injury Scale (CRIS) has been completed for all major medical specialties. The CRIS separates the various criteria (energy dissipation-ED, threat to life-TL, permanent impairment-PI, treatment period-TP, incidence-IN) used with variable quantities and frequencies in the AIS. The CRIS identifies and quantitates each scaling criteria permitting more meaningful and detailed application of the AIS.

This three-part paper deals with the medical aspects of driver protection in automobile racing. Part one presents the history of car safety equipment beginning with the development of helmets, belts, roll bars, and other devices to protect competition drivers. This paper describes the evolution from purely optional to mandatory equipment and how their design and accident records have contributed to increased safety in passenger cars. The investigation of injuries sustained in crash, fire, and loss of control caused by road hazards have contributed to the many improvements discussed here, almost all of which are readily adaptable to passenger car models. The second part presents a summary of the influence of racing on the design, testing and performance standards for protective headgear. The significance is indicated of applying basic principles of mechanics and dynamic systems testing to all fields in which head impact is a potential hazard.

Some 634 accidents occuring in races sanctioned by the Sports Car Club of America (SCCA) are reviewed. Shoulder harnesses were used in 275 of the accidents. Inverted “Y” or double, separately anchored, shoulder harnesses were used almost exclusively. A significant decrease in the frequency and severity of injuries occurred after harnesses were introduced. Injury from the restraint system was very infrequent; submarining occurred only once. Deep bucket seats, providing lateral support for the chest and forward support for the buttocks, appear to potentiate the effectiveness of restraint systems. The “Y” harness functions well in production seats without lateral support because lateral displacement of the shoulders and upper torso can occur without risk of neck injury.