Search

In experiments to investigate the relationship between head impacts and changes in vital functions, translational and rotational acceleration impacts were performed on live monkeys using a head restraint mask with broad contact area, as well as impacts of the unrestrained head against a padded flat surface. The results indicate that the occurrence and severity of concussion, cerebral contusion, and skull fracture in the monkeys depended on translational vs. rotational impact, contact area size, amplitude and direction of the resultant head acceleration, and frontal vs. occipital impact direction. The occurrence of concussion indicated the tolerance threshold, representing a transitory and reversible disturbance of vital functions. A threshold of concussion occurrence (TCO) curve was derived. The occurrence of skull fracture indicated the danger threshold (severe or fatal brain injury likely). Free-drop impact experiments were conducted on human cadaver skulls to obtain a fracture threshold curve. The dimensional analysis method of Stalnaker et al. was applied to the monkey TCO to estimate the human TCO. Combining this with the human cadaver skull fracture threshold, a human head impact tolerance threshold was derived.

During a 5-month period a study was made of motor vehicle occupants presenting at an Accident and Emergency department following an accident. Records were made of the incidence of neck injuries in relation to the presence of head restraints and the use of seat belts. There was a slight reduction in injuries when a head restraint was fitted but this difference did not achieve statistical significance. The incidence of neck injury was not increased if a seat belt was worn. It may be that the reason for the failure of head restraints to afford the expected protection is their inappropriate design and lack of adequate adjustability.

A review of the existing mathematical models of a car occupant in a rear-end crash reveals that existing models inadequately describe the kinematics of the occupant and cannot demonstrate the injury mechanisms involved. The paper shows the results of a 78 degree-of-freedom model of the spine, head, and pelvis which has already been validated in plus G//z and minus G//x acceleration directions. It considers automotive-type restraint systems, seat back, and seat cushions, and the torso is free to slide up the seat back. Results of simulation runs show a good correlation with the existing data and experimental cadaveric runs made with a high seat back (or head restraint) and low seat back. The effect of seat-back stiffness and the restraint system on the response of the head and spine is studied. Language: en

Two stainless steel bolts were implanted and fixed parallel in the frontal sinus of cats with dental acrylic and screws. When unanaesthetized, the head was fixed to a frame by securing the bolts to an acrylic plate. This arrangement provides a quick, rigid and safe fixation of the head without any signs of discomfort.

An inexpensive light weight head restraint device enabling horizontal rotational head movements is described. The restrainer provides sufficient stability to allow prolonged single unit recording and is compatible with conventional recording techniques.

A method is described for attaching a restraint pedestal to the skull of rhesus monkeys. This device can be used for recording electrophysiologic data in almost any experiment that requires the animal to be awake but unable to move its head. When meticulous technique has been employed, the animal's life expectancy is not shortened. The majority of our animals have been maintained with pedestals for periods of 12–14 months.

A series of rear impact tests of varying severity was performed using a mini pick-up truck with an instrumented Hybrid III dummy at the driver position. Head, neck and chest loads were monitored. The severities of these loads from an injury standpoint were assessed using biomechanically based reference criteria that are particularly suitable for the Hybrid III. The glass installation performed well as a head restraint. Glass fracture from head impact was achieved only when the glass was predamaged, with surface scratches on the outer (tensile) side. The amazing strength and flexibility of tempered glass and the dramatic reduction in strength caused by small surface scratches are demonstrated.

The purpose of this monograph is to describe trends in the interior safety of cars in terms of the frequency and severity of injuries among the car occupants, especially the drivers. Special references are made to the influence of the weight of the car, the starting year of production of the car, and some safety devices such as safety belts and head rest fittings. The material comprises all accident-involved private cars reported to an insurance company during a five-year period. The total number of such cars was 339,675 in which 8,592 drivers and 5,469 passengers were injured or killed. This represents approximately one-fourth of all accident-involved cars reported to insurance companies during a five-year period in Sweden. Data which are normally stored in the insurance files have been supplemented with data concerning car weight and starting year of production of the cars. In injury-producing accidents hospital records and doctors' certificates were available in the majority of cases, as well as reports from the police investigations. All data were computerised. An additive regression model was used to determine the influence of car weight, starting year of production of the car model, age of the car, safety belt usage and fitting of head rests, on the frequency of injuries. Data concerning car occupants with permanent medical disability and financial disability were specially investigated to gain information on what type of injuries lead to major problems in later years. A sample of car occupants with head injuries was investigated to study the frequency of problems remaining in later years. The main conclusions reached are that the weight of the striking car as well as of the struck car influences the injury frequency and severity of injuries among drivers. The knowledge of impact biomechanics accumulated since the middle of the sixties seems to have improved the interior safety of cars. The results of the regression analysis implied that some of the small new cars have the same safety level as large old ones. Safety-belt usage diminishes the severity of injuries and the risk of fatalities and it is proposed that the use of safety belts should also be compulsory in the rear seat.(ABSTRACT TRUNCATED AT 400 WORDS)

This effort resulted in the design and construction of a crash sensing system for military helicopters to be used to electrically detonate the squibs of an inflatable body and head restraint system (IBAHRS) during a crash. Calibration sensitivity levels were established through computer simulations using acceleration data collected in previous helicopter crash tests. The sensor system is sensitive enough to deploy the IBAHRS in time for it to be effective but not so sensitive that inadvertent firings occur due to expected acceleration levels of flight maneuvers, vibrations, and landings.

• Maintaining endotracheal intubation is critical to treating respiratory failure in newborns. To reduce accidental extubations in our neonatal intensive care unit, a prospective comparison of rates of extubation was made between two taping methods and whether or not a head restraint was used. One tape method was significantly better at preventing accidental extubations. Head restraint was not a benefit when used prospectively. Factors that preceded or were associated with accidental extubation included the time intubated, infant agitation, endotracheal tube suctioning, the infant turning its head, chest physiotherapy, loose tape, too short a tube between lip and adapter, weighing, and endotracheal tube taping. This information and the study design are valuable in developing strategies to minimize accidental endotracheal extubation and the subsequent risks of airway injury and subglottic stenosis in sick newborns. ( AJDC 1988;142:1240-1243)

An adjustable, stainless steel, head restraining device and small screw-tightened skull clips are described which enable us to record single unit neuronal activity chronically from awake, behaving primates of various sizes. We have used this method of head restraint over the past 4 years on 8 primates, for periods up to 18 months without any mechanical failures. This equipment reduces problems stemming from bone necrosis and is well tolerated.

A method for head and body restraint is described which allows long-term micro-electrode recording of pontomedullary brain-stem units of cats. Mechanical restraint is achieved by securing bolts projecting from a headplate to a steel arch in a box. Adaptation to the box is enhanced by the strategic use of sleep deprivation.

To the Editor.— We are writing to demonstrate an unusual traumatic result related to one of the safety features of our modern automobiles. This 14-year-old girl was riding in the rear seat of an automobile which was involved in an accident, without a seat belt on. She was thrown forward and struck the upper part of her chest on the front seat head restraint, breaking both clavicles in midshaft (Figure). Her attending physicians considered it miraculous that she did not sustain possibly fatal tracheal or laryngeal trauma at the same time. This points out two things: first, the value of rear seat safety belts and second, that head restraints in the front seat possibly should be redesigned to allow some forward motion in order to prevent such an accident as this.

All of the rear-end impact accidents occurring in the City of Rochester, New York, in a three-month period were surveyed by tabliation 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 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. Seventy percent of adjustable head restraints were in the downmost position. Women sustained whiplash injury more frequently (51%) but benefited from head restraints more (whiplash injury frequency 38%). An extensive review of the literature related to whiplash injury and head restraint design and effectiveness is presented. /Author/

STARTING WITH TWO-DIMENSIONAL COMPUTER SIMULATIONS OF FRONT SEAT OCCUPANT KINEMATICS IN REAR-END COLLISIONS, INITIAL PERFORMANCE CRITERIA FOR DEPLOYMENT TIMES, AND RESTRAINT CONFIGURATIONS WERE DETERMINED FOR VARIOUS IMPACT VELOCITIES. BASED ON THESE CRITERIA, TWO TYPES OF DEPLOYABLE SYSTEMS WERE DESIGNED AND CONSTRUCTED, ONE AN INFLATABLE SYSTEM AND THE OTHER A RIGID SLIDING SYSTEM. THESE PROTOTYPE SYSTEMS THEN UNDERWENT A TEST AND DEVELOPMENT PROGRAM USING ANTHROPOMORPHIC DUMMIES AND AN IMPACT SLED. THE TEST PROGRAM EVALUATED THE EFFECTIVENESS OF THE HEAD RESTRAINT SYSTEMS UNDER HIGH- AND LOW-SPEED CRASH SIMULATIONS. IN ADDITION, TESTS WERE PERFORMED TO STUDY THE EFFECT OF RESTRAINT DEPLOYMENT ON THE MALPOSITIONED OCCUPANT. THE RESULTS OF THE TEST PROGRAM ARE DISCUSSED AND COMPARISONS ARE MADE BETWEEN THE TWO PROTOTYPE SYSTEMS AND EXISTING HEAD RESTRAINT DESIGNS. /SAE/

ACCIDENT CASES INVOLVING CARS WITHOUT HEAD RESTRAINTS ARE COMPARED WITH CARS HAVING THIS DEVICE TO EVALUATE THE EFFECTIVENESS OF HEAD RESTRAINTS, THEIR POSITION WHEN IMPACT OCCURRED, AND TO PROVIDE SOME DETAILS CONCERNING THE RELATIONSHIP BETWEEN OCCUPANT POSITION, SEAT BACK DAMAGE, AND CERVICAL INJURY. A REDUCTION IN NONDANGEROUS CERVICAL INJURY WAS ASSOCIATED WITH THE HEAD RESTRAINT GROUP. HOWEVER, DUE TO SMALL NUMBERS THIS COULD NOT BE CONFIRMED STATISTICALLY. APPROXIMATELY 73% OF THE ADJUSTABLE HEAD RESTS WERE IN THEIR LOWEST POSITION. THE POSITION OF THE OCCUPANT ON THE SEAT STRONGLY INFLUENCED INJURY. LARGER AMOUNTS OF REARWARD ROTATION OF THE SEAT BACK WERE ASSOCIATED WITH LOWER INJURY SEVERITY THAN LIMITED ROTATION. /SAE/

A SERIES OF EXPERIMENTS WERE CONDUCTED TO EVALUATE THE RELATIVE PROTECTIVE MERITS AND THE PRACTICALITY OF VARIOUS SEAT DESIGNS WITH RESPECT TO THE MANY VARIABLES COMMON TO REAR-END COLLISIONS IN THE FOLLOWING SECTIONS: (1) BACKGROUND REVIEWS FOUR EARLIER STUDIES. (2) FACILITIES AND EQUIPMENT DESCRIBES THE UCLA-ITTE FIELD STATION FOR COLLISION RESEARCH. (3) EXPERIMENTAL PROCEDURE REVIEWS THE IMPACT SPEEDS, TYPES OF DUMMIES, AND SEAT BACK HEIGHTS USED IN THE TWELVE COLLISIONS OF THE EXPERIMENT. (4) METHODOLOGY DISCUSSES THE STANDARDIZED EXPERIMENTATION PROCEDURES (IMPACT CONFIGURATIONS, DIRECTIONAL HEADING OF COLLIDING CARS, DIRECTIONAL CONTROL OF THE APPROACHING STRIKING VEHICLE, AND SPEED CONTROL) AND THE SPECIAL TECHNIQUES PECULIAR TO THIS COLLISION SERIES (MODIFICATION OF SEAT ARRANGEMENTS, BODY REVISIONS, HUMAN SIMULATION WITH ANTHROPOMORPHIC DUMMIES, DUMMY SIZE TO SEAT BACK HEIGHT RELATIONSHIPS, AND OCCUPANT ASSIGNMENTS). (5) INSTRUMENTATION DESCRIBES THE MEANS BY WHICH VARIOUS DATA WERE COLLECTED: HIGH SPEED MOTION PICTURE CAMERAS TO RECORD VEHICLE COLLISION DYNAMICS AND PASSENGER KINEMATICS; ELECTRICAL ACCELEROMETERS; SEAT BELT TENSIOMETERS TO MEASURE BELT LOADS; FIFTH WHEEL TO ASSURE ACCURATE IMPACT VELOCITY; REFERENCE TARGETS TO PROVIDE PRECISION PHOTOGRAPHIC REFERENCES FOR MICROMOTION ANALYSIS; AND, A RECORDING OSCILLOGRAPH FOR AMPLITUDE-TIME RECORDS OF TRANSDUCER SIGNALS; ETC. SPECIFICATIONS FOR THE INSTRUMENTS ARE INCLUDED. (6) ANALYSIS AND FINDINGS PRESENTS THE DATA COLLECTED IN THE FOLLOWING AREAS: VEHICLE COLLISION PERFORMANCE, AND PEAK ACCELERATION; PASSENGER KINEMATICS AND PEAK ACCELERATIONS; WHIPLASH PROTECTION PROVIDED BY VARIOUS SEATBACK HEIGHTS AND STRENGTHS, AS WELL AS RELATED DESIGN INNOVATIONS; TRANSDUCER PATTERNS OF OCCUPANTS, VEHICLES, RESTRAINT SYSTEMS, HEAD RESTRAINTS, AND SEAT STRUCTURES, AND DESCRIPTION OF POST CRASH OBSERVATIONS. (7) EXPERIMENTS GIVE THE PARTICULARS OF EACH OF THE TWELVE COLLISIONS, A REPORT OF THE INJURIES SUSTAINED BY EACH PASSENGER, AND DATA ON THE CONDITION OF THE VEHICLES AND SEAT BACKS. (8) DISCUSSION PROVIDES DESIGN CRITERIA NEEDED BY THE AUTOMOTIVE MANUFACTURERS CONCERNED WITH PROVIDING SAFER SEAT DESIGNS IN THE FOLLOWING AREAS: VEHICLE SEAT MODIFICATION, VEHICLE COLLISION PERFORMANCE, AND HEAD RESTRAINT PERFORMANCE. (9) CONCLUSIONS LIST FINDINGS WITH RESPECT TO METHODOLOGY, COLLISION PERFORMANCE, PASSENGER COMPARTMENT DESIGN, SEAT DESIGN, HEAD RESTRAINTS, OCCUPANT PROTECTION, ETC. APPENDICES: A IS REAR- END COLLISION TRANSDUCER DATA; B IS ANTHROPOMETRIC ADULT DUMMY SPECIFICATIONS. /SRIS/

THIS PAPER DISCUSSES THE PROBLEM OF OCCUPANT PROTECTION IN SEVERE REAR END COLLISIONS FROM THE STANDPOINT OF HIGH PERFORMANCE SEAT STRUCTURES AND HEAD RESTRAINTS. CONSIDERATION IS GIVEN TO BOTH FIXED HEAD RESTRAINTS AND TO DEPLOYABLE HEAD RESTRAINTS. TWO-DIMENSIONAL COMPUTER SIMULATIONS OF OCCUPANT KINEMATICS IN A VARIETY OF REAREND COLLISIONS ARE UTILIZED TO PROVIDE INITIAL PERFORMANCE CRITERIA FOR HEAD RESTRAINT DESIGN CONFIGURATIONS. THE RESULTING PROTOTYPE SYSTEM UNDERWENT A TEST AND DEVELOPMENT PROGRAM ON AN IMPACT SLED. THE RESULTS OF THE VARIOUS PROTOTYPE PERFORMANCES AND GENERAL CRITERIA FOR HIGH PERFORMANCE HEAD RESTRAINT SYSTEMS ARE DISCUSSED. /SAE/

The objective of this study was to present the design of a prototype rear impact crash test dummy, representing a 50th percentile female, and compare its performance to volunteer response data. The intention was to develop a first crude prototype as a first step toward a future biofidelic 50th percentile female rear impact dummy. The current rear impact crash test dummy, BioRID II, represents a 50th percentile male, which may limit the assessment and development of whiplash protection systems with regard to female occupants. Introduction of this new dummy size will facilitate evaluation of seat and head restraint (HR) responses in both the average sized female and male in rear impacts. A 50th percentile female rear impact prototype dummy, the BioRID P50F, was developed from modified body segments originating from the BioRID II. The mass and rough dimensions of the BioRID P50F is representative of a 50th percentile female. The prototype dummy was evaluated against low severity rear impact sled tests comprising six female volunteers closely resembling a 50th percentile female with regard to stature and mass. The head/neck response of the BioRID P50F prototype resembled the female volunteer response corridors. The stiffness of the thoracic and lumbar spinal joints remained the same as the average sized male BioRID II, and therefore likely stiffer than joints of an average female. Consequently, the peak rearward angular displacement of the head and T1, and the rearward displacement of the T1, were lesser for the BioRID P50F in comparison to the female volunteers. The biofidelity of the BioRID P50F prototype thus has some limitations. Based on a seat response comparison between the BioRID P50F and the BioRID II, it can be concluded that the male BioRID II is an insufficient representation of the average female in the assessment of the dynamic seat response and effectiveness of whiplash protection systems.

This report describes a closed system audio helmet for monkeys which is both reliable and inexpensive. The need for head restraint is eliminated and also permits self-feeding. No problem was experienced in the daily fitting of the helmet; the operation required less than 5 minutes. (Author)

The authors briefly describe the lesions sustained by 38 patients admitted to a neurosurgical service between 1970 and 1984. All patients had fractures of the pedicles of c-2. 35 of these patients sustained their injuries in car accidents, three-quarters of which were frontal collisions. 28 of these 35 patients were wearing safety belts, but had no head rest. The remaining 7 were not wearing safety belts. These numbers indicate that the wearing of safety belts without head rests lends itself to this type of injury (TRRL)

A study in progress requires that monkeys (Macaca species) be implanted with a chronic in-dwelling catheter through which drugs may be administered under conditions of minimal restraint and without handling the animal. Although complex and multipurpose head restraint systems do exist [Findley, Jack, Personal communication, 1967], a relatively lightweight, inexpensive and easily fabricated system has been developed which admirably fulfills this requirement. To date, Macaca iris and Macaca mulatta subjects weighing up to 8.62 kg (19 lb) have been fitted to the restraint system without complications.