Development of Biomechanical Response Corridors of the Head to Blunt Ballistic Temporo-Parietal Impact

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
David Raymond ◽  
Greg Crawford ◽  
Chris Van Ee ◽  
Cynthia Bir
Keyword(s):  
Head Impact ◽  
Ballistic Impact ◽  
Peak Force ◽  
Future Research ◽  
Parietal Region ◽  
Impact Studies ◽  
Time Deformation ◽  
Impact Condition ◽  
Body Regions ◽  
Biomechanical Response

There is a need to study the biomechanical response of the head to blunt ballistic impact. While the frequency of less-lethal munition impacts to the head may be less than other vital body regions, more serious injuries have been attributed to these impacts. This study aims to establish biomechanical response corridors for the temporo-parietal region for future development of biomechanical surrogate devices. Seven unembalmed post-mortem human subject specimens were exposed to blunt ballistic temporo-parietal head impact (103 g, 38 mm diameter impactor) to determine the force-time, deformation-time, and force-deformation responses. Comparisons were made to responses from prior blunt ballistic head impact studies, as well as automotive-related impact studies. Peak forces for impact condition A (19.5±2.6 m/s) were 3659±1248 N with deformations at peak force of 7.3±2.1 mm. Peak forces for impact condition B (33.6±1.4 m/s) were 5809±1874 N with deformations at peak force of 9.9±2.6 mm. Seven fractures were produced in the seven specimens. Depressed comminuted fracture types were documented in six of the seven cases. The average stiffness of the temporo-parietal region under blunt ballistic impact was 0.46±0.14 kN/mm. Stiffness results indicate that the response of the temporo-parietal region is similar to the forehead under blunt ballistic loading conditions. In addition, the response is significantly less stiff when compared with temporo-parietal impacts performed in automotive-related studies. These data provide the foundation for future research in the area of blunt ballistic head impact research including the development of biomechanical surrogates and computational models.

The Effect of Soft Tissue on the Biomechanics of Skull Fracture due to Blunt Ballistic Impact: Preliminary Analysis and Findings

2008 ◽  
Author(s):  
David E. Raymond ◽  
Greg S. Crawford ◽  
Chris A. Van Ee ◽  
Cynthia A. Bir
Keyword(s):  
Soft Tissue ◽  
Skull Fracture ◽  
Human Head ◽  
Ballistic Impact ◽  
Impact Response ◽  
Parietal Region ◽  
Small Surface ◽  
Body Regions ◽  
Biomechanical Response ◽  
Fracture Tolerance

The majority of engineering studies that quantify the biomechanical response of the human head to blunt impacts have been focused primarily on replicating automotive-related trauma [1]. Relatively little biomechanical data exists on head response and skull fracture tolerance due to impacts with small surface area objects moving at high velocity, as can occur with the deployment of less-lethal kinetic energy munitions that are now available to police and military personnel. Law enforcement are trained to direct such munitions away from the head and at body regions least likely to sustain serious to life-threatening injury, such as the legs, however impacts to vital regions such as the head have occurred [2]. Previous research efforts have investigated facial impact response to blunt ballistic impacts however data regarding the temporo-parietal region are lacking and require study under these unique loading conditions [3]. Prior research has indicated that the scalp and soft tissue covering the skull are important factors to consider when studying impact response and skull fracture tolerance [4]. These data however have been limited primarily to impact velocities typical of the automotive crash environment. The purpose of this study is to evaluate the contribution of soft tissue to the biomechanical response and tolerance of the temporo-parietal region under blunt ballistic impact conditions.

Biomechanics of Temporo-Parietal Skull Fracture From Blunt Ballistic Impact

2008 ◽  
Author(s):  
David E. Raymond ◽  
Greg S. Crawford ◽  
Chris A. Van Ee ◽  
Cynthia A. Bir
Keyword(s):  
Skull Fracture ◽  
Ballistic Impact ◽  
Minimal Risk ◽  
Small Surface ◽  
Human Skull ◽  
Ballistic Impacts ◽  
Body Regions ◽  
Biomechanical Response ◽  
Strain Data ◽  
Fracture Tolerance

The majority of engineering studies that quantify the biomechanical tolerance of the human skull to blunt impacts have been focused primarily on replicating automotive-related trauma [1]. Relatively little biomechanical data exists on skull fracture tolerance due to impacts with small surface area objects moving at high velocity, previously defined as blunt, ballistic impacts [2]. These impacts can occur with the deployment of less-lethal kinetic energy munitions that are now available to police and military personnel. The goal of less-lethal munitions is to impart sufficient force to a subject to deter uncivil, or hazardous, behavior with minimal risk for serious or fatal injury. A basic understanding of human biomechanical response and tolerance to blunt ballistic impact is needed for all areas of the human body in order to guide the design of such munitions. Law enforcement are trained to direct such munitions away from the head and at body regions such as the legs, however impacts to the head have occurred [3]. Previous research efforts have investigated facial impact tolerance to blunt ballistic impacts [4] however data regarding the temporo-parietal region are lacking. The goal of this research project is to provide basic bone strain data on temporo-parietal skull fracture for the purpose of developing finite element models of the human skull and fracture criterion for future study of blunt ballistic head impact.

scholarly journals In Search of Alignment: A Review of Impact Studies in Entrepreneurship Education

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Uladzimir Kamovich ◽  
Lene Foss
Keyword(s):  
Empirical Studies ◽  
Entrepreneurship Education ◽  
Analytical Framework ◽  
Future Research ◽  
Impact Studies ◽  
Teaching Objectives ◽  
Teaching Content ◽  
Instructional Processes ◽  
Scant Attention ◽  
The Impact

This study uses the concept of alignment as a framework to examine empirical research on the impact of entrepreneurship education interventions on students. Alignment assumes that effective instruction requires congruence between three instructional components: intended outcomes, instructional processes, and assessment criteria. Given the extant diversity and complexity of entrepreneurship education impact, scholars have not been able to explain how teaching approaches and methods are being adjusted to the variety of expected outcomes. In order to address this gap, we critically reviewed the published empirical studies on entrepreneurship education impact in 20 journals over a 15-year period (2000–2015). We found 16 empirical studies that met our inclusion criteria. Our findings revealed that teaching objectives, teaching methods, and teaching content receive scant attention from researchers. This study will be of value to scholars researching the impact of heterogeneous entrepreneurship education practices and approaches on individuals. Our analytical framework could contribute to less contradictory findings of entrepreneurship education impact studies. We also identify research limitations and suggest avenues for future research.

scholarly journals Characterization of fatal injuries in oil and gas industry-related helicopter accidents in the Gulf of Mexico, 2004–2014

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kristin Yeoman ◽  
Mary B. O’Connor ◽  
Sara Sochor ◽  
Gerald Poplin
Keyword(s):  
Lower Extremity ◽  
Gulf Of Mexico ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Body Region ◽  
Future Research ◽  
Gas Industry ◽  
Body Regions ◽  
Safety Features

Abstract Background Transportation events are the most common cause of offshore fatalities in the oil and gas industry, of which helicopter accidents comprise the majority. Little is known about injury distributions in civilian helicopter crashes, and knowledge of injury distributions could focus research and recommendations for enhanced injury prevention and post-crash survival. This study describes the distribution of injuries among fatalities in Gulf of Mexico oil and gas industry-related helicopter accidents, provides a detailed injury classification to identify potential areas of enhanced safety design, and describes relevant safety features for mitigation of common injuries. Methods Decedents of accidents during 2004–2014 were identified, and autopsy reports were requested from responsible jurisdictions. Documented injuries were coded using the Abbreviated Injury Scale (AIS), and frequency and proportion of injuries by AIS body region and severity were calculated. Injuries were categorized into detailed body regions to target areas for prevention. Results A total of 35 autopsies were coded, with 568 injuries documented. Of these, 23.4% were lower extremity, 22.0% were thorax, 13.6% were upper extremity, and 13.4% were face injuries. Minor injuries were most prevalent in the face, neck, upper and lower extremities, and abdomen. Serious or worse injuries were most prevalent in the thorax (53.6%), spine (50.0%), head (41.7%), and external/other regions (75.0%). The most frequent injuries by detailed body regions were thoracic organ (23.0%), thoracic skeletal (13.3%), abdominal organ (9.6%), and leg injuries (7.4%). Drowning occurred in 13 (37.1%) of victims, and drowning victims had a higher proportion of moderate brain injuries (7.8%) and lower number of documented injuries (3.8) compared with non-drowning victims (2.9 and 9.4%, respectively). Conclusions Knowledge of injury distributions focuses and prioritizes the need for additional safety features not routinely used in helicopters. The most frequent injuries occurred in the thorax and lower extremity regions. Future research requires improved and expanded data, including collection of detailed data to allow characterization of both injury mechanism and distribution. Improved safety systems including airbags and helmets should be implemented and evaluated for their impact on injuries and fatalities.

scholarly journals Spectrum of acute clinical characteristics of diagnosed concussions in college athletes wearing instrumented helmets

2012 ◽  
Vol 117 (6) ◽  
pp. 1092-1099 ◽  
Author(s):  
Ann-Christine Duhaime ◽  
Jonathan G. Beckwith ◽  
Arthur C. Maerlender ◽  
Thomas W. McAllister ◽  
Joseph J. Crisco ◽  
...  
Keyword(s):  
Collegiate Athletes ◽  
Head Impact ◽  
Ice Hockey ◽  
Future Research ◽  
Impact Event ◽  
Head Impacts ◽  
Presenting Symptoms ◽  
Wide Range ◽  
Impact Events ◽  
Specific Impact

Object Concussive head injuries have received much attention in the medical and public arenas, as concerns have been raised about the potential short- and long-term consequences of injuries sustained in sports and other activities. While many student athletes have required evaluation after concussion, the exact definition of concussion has varied among disciplines and over time. The authors used data gathered as part of a multiinstitutional longitudinal study of the biomechanics of head impacts in helmeted collegiate athletes to characterize what signs, symptoms, and clinical histories were used to designate players as having sustained concussions. Methods Players on 3 college football teams and 4 ice hockey teams (male and female) wore helmets instrumented with Head Impact Telemetry (HIT) technology during practices and games over 2–4 seasons of play. Preseason clinical screening batteries assessed baseline cognition and reported symptoms. If a concussion was diagnosed by the team medical staff, basic descriptive information was collected at presentation, and concussed players were reevaluated serially. The specific symptoms or findings associated with the diagnosis of acute concussion, relation to specific impact events, timing of symptom onset and diagnosis, and recorded biomechanical parameters were analyzed. Results Data were collected from 450 athletes with 486,594 recorded head impacts. Forty-eight separate concussions were diagnosed in 44 individual players. Mental clouding, headache, and dizziness were the most common presenting symptoms. Thirty-one diagnosed cases were associated with an identified impact event; in 17 cases no specific impact event was identified. Onset of symptoms was immediate in 24 players, delayed in 11, and unspecified in 13. In 8 cases the diagnosis was made immediately after a head impact, but in most cases the diagnosis was delayed (median 17 hours). One diagnosed concussion involved a 30-second loss of consciousness; all other players retained alertness. Most diagnoses were based on self-reported symptoms. The mean peak angular and rotational acceleration values for those cases associated with a specific identified impact were 86.1 ± 42.6g (range 16.5–177.9g) and 3620 ± 2166 rad/sec2 (range 183–7589 rad/sec2), respectively. Conclusions Approximately two-thirds of diagnosed concussions were associated with a specific contact event. Half of all players diagnosed with concussions had delayed or unclear timing of onset of symptoms. Most had no externally observed findings. Diagnosis was usually based on a range of self-reported symptoms after a variable delay. Accelerations clustered in the higher percentiles for all impact events, but encompassed a wide range. These data highlight the heterogeneity of criteria for concussion diagnosis, and in this sports context, its heavy reliance on self-reported symptoms. More specific and standardized definitions of clinical and objective correlates of a “concussion spectrum” may be needed in future research efforts, as well as in the clinical diagnostic arena.

Manned Evaluation of a Prototype Cold Water Diving Garment Using Superinsulation Aerogel Materials

2006 ◽  
Author(s):  
Marshall Nuckols ◽  
Jerry Henkener ◽  
Jeffrey Chao ◽  
Chris Shaffer ◽  
Matthew Swiergosz
Keyword(s):  
Repeated Measures ◽  
Thermal Protection ◽  
Cold Water ◽  
Future Research ◽  
Body Regions ◽  
Long Duration ◽  
Thermal Status ◽  
Test Pool ◽  
Hands And Feet ◽  
Status Data

During January 2005, the U. S. Navy Experimental Diving Unit (NEDU) in Panama City, Florida conducted a repeated measures series of twelve test dives, each up to three hours in duration, to compare the thermal performance of a prototype diving garment using a superinsulation aerogel fabric with that of a commercially-available Thinsulate garment worn beneath a commercial dry suit. The thermal benefit of the experimental aerogel garment was determined by statistics describing psychological and physical thermal status data from the aerogel and the commercial Thinsulate garments. All tests were conducted to simulate long-duration cold water conditions in the NEDU test pool, where water temperature was maintained between 1.7 and 4.4 °C (35 and 40 °F). Divers remained immobile while either lying or sitting in chairs on the bottom of the test pool, and they subjectively reported their thermal comfort at 30-minute intervals during each dive. Mean dive durations were found to be approximately 43% longer when divers wore the prototype aerogel garment than when they wore an M400 Thinsulate liner. The prototype aerogel garment also enhanced thermal protection to the fingers and toes, although thermal stress to these body regions still remained the most frequent reason for aborting dives. Future research should include work on localized active heating of the hands and feet to augment the thermal insulation of the prototype aerogel garment.

scholarly journals Comparing head impact kinematics simultaneously measured using 6 different sensors in a human cadaver model

Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S2.3-S3
Author(s):  
James T. Eckner ◽  
R. Scott Conley ◽  
Hugh J.L. Garton ◽  
Nikki Weiss ◽  
Lauro Ojeda ◽  
...  
Keyword(s):  
Intraclass Correlation ◽  
Head Impact ◽  
Future Research ◽  
Back Side ◽  
Orthodontic Appliance ◽  
Male Specimen ◽  
Total N ◽  
Head Kinematics ◽  
Free Drop ◽  
Reference Sensor

ObjectiveTo compare head kinematics measurements obtained from 6 different head impact sensors utilizing different methods of sensor-to-head fixation.DesignFree-drop impacts (total n = 54) were performed at 3.5 and 5.5 m/s onto to the front, back, side, and top of 2 elderly human cadaveric head-neck specimens: a helmeted (Riddell Revolution Speed) male specimen was dropped onto a NOCSAE testing pad; an un-helmeted female specimen was dropped onto a framed sample of field turf. The specimens were instrumented with an intracranial reference sensor surgically mounted at the approximate head center-of-mass by a rigidly-fixed custom standoff pad, an intra-oral test sensor rigidly fixed to the upper teeth/hard palate by a custom orthodontic appliance, and 4 commercially available head impact sensing systems: X-Patch, Vector mouth guard, HITS (helmeted condition only), and G-Force Tracker (affixed to helmet interior or head band depending on helmet status). Peak linear and rotational head accelerations (PLA and PRA) were compared between each sensor and the intracranial reference sensor using intraclass correlation coefficients (ICC [2, 1]).ResultsAgreement with reference PLA and PRA values differed between sensors, with the greatest agreement observed for the rigidly affixed intraoral sensor (ICC = 0.921, PLA; ICC = 0.810, PRA). Agreement for PLA and PRA, respectively, was: for X-Patch, ICC = 0.638, ICC = 0.155; for Vector mouth guard, ICC = 0.775, ICC = 0.480; for HITS, ICC = 0.662 (PLA only); for G-Force Tracker, ICC = 0.364 (PLA only).DiscussionHead kinematics measurements during free-drop testing differed among sensors using different approaches of fixation to the head. There was greater agreement with intracranial reference PLA and PRA values for a rigidly affixed intraoral sensor utilizing an orthodontic appliance than for commercially available sensors incorporated into athletic equipment or otherwise non-rigidly affixed to the head. Measurement error attributable to non-rigid sensor-head coupling could potentially be reduced by incorporating an impact sensor into an orthodontic appliance in future research.

scholarly journals Comparisons of eccentric knee flexor strength and asymmetries across elite, sub-elite and school level cricket players

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1594 ◽  
Author(s):  
Wade J. Chalker ◽  
Anthony J. Shield ◽  
David A. Opar ◽  
Justin W.L. Keogh
Keyword(s):  
Skill Level ◽  
Peak Force ◽  
School Level ◽  
Future Research ◽  
Force Output ◽  
Skill Levels ◽  
Injury Rates ◽  
Knee Flexor ◽  
Hamstring Strain ◽  
Flexor Strength

Background.There has been a continual increase in injury rates in cricket, with hamstring strain injuries (HSIs) being the most prominent. Eccentric knee flexor weakness and bilateral asymmetries are major modifiable risk factors for future HSIs. However, there is a lack of data relating to eccentric hamstring strength in cricket at any skill level. The objective of this study was to compare eccentric knee flexor strength and bilateral asymmetries in elite, sub-elite and school level cricket players; and to determine if playing position and limb role influenced these eccentric knee flexor strength indices.Methods.Seventy four male cricket players of three distinct skill levels performed three repetitions of the Nordic hamstring exercise on the experimental device. Strength was assessed as the absolute and relative mean peak force output for both limbs, with bilateral asymmetries. Differences in mean peak force outputs between skill level and playing positions were measured.Results.There were no significant differences between elite, sub-elite and school level athletes for mean peak force and bilateral asymmetries of the knee flexors. There were no significant differences observed between bowler’s and batter’s mean peak force and bilateral asymmetries. There were no significant differences between front and back limb mean peak force outputs.Discussion.Skill level, playing position and limb role appeared to have no significant effect on eccentric knee flexor strength and bilateral asymmetries. Future research should seek to determine whether eccentric knee flexor strength thresholds are predictive of HSIs in cricket and if specific eccentric knee flexor strengthening can reduce these injuries.

scholarly journals Staged Approach for Rehabilitation Classification: Shoulder Disorders (STAR–Shoulder)

2015 ◽  
Vol 95 (5) ◽  
pp. 791-800 ◽  
Author(s):  
Philip W. McClure ◽  
Lori A. Michener
Keyword(s):  
Classification System ◽  
Medical Model ◽  
Reliability And Validity ◽  
Treatment Decision ◽  
Potential Method ◽  
Future Research ◽  
Musculoskeletal Problem ◽  
Diagnostic Categories ◽  
Body Regions ◽  
Shoulder Disorders

Shoulder disorders are a common musculoskeletal problem causing pain and functional loss. Traditionally, diagnostic categories are based on a pathoanatomic medical model aimed at identifying the pathologic tissues. However, the pathoanatomic model may not provide diagnostic categories that effectively guide treatment decision making in rehabilitation. An expanded classification system is proposed that includes the pathoanatomic diagnosis and a rehabilitation classification based on tissue irritability and identified impairments. For the rehabilitation classification, 3 levels of irritability are proposed and defined, with corresponding strategies guiding intensity of treatment based on the physical stress theory. Common impairments are identified and are used to guide specific intervention tactics with varying levels of intensity. The proposed system is conceptual and needs to be tested for reliability and validity. This classification system may be useful clinically for guiding rehabilitation intervention and provides a potential method of identifying relevant subgroups in future research studies. Although the system was developed for and applied to shoulder disorders, it may be applicable to classification and rehabilitation of musculoskeletal disorders in other body regions.

scholarly journals Age-Related Differences in Head Impact during Experimentally Induced Sideways Falls

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Tyler A. Wood ◽  
Yaejin Moon ◽  
Ruopeng Sun ◽  
Alka Bishnoi ◽  
Jacob J. Sosnoff
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Young Group ◽  
Head Impact ◽  
Future Research ◽  
Head Acceleration ◽  
Head Impacts ◽  
Age Related ◽  
Risk Of Fall ◽  
Experimentally Induced

Purpose. To examine head impact incidence and head acceleration during experimentally induced falls as a function of age.Methods. 15 young adults (21.2±2.7) and 10 older adults (61.9±4.3 years) underwent 6 experimentally induced sideways falls. Participants fell sideways onto a 20cm crash pad. The number of head impacts was tabulated from video recordings and head acceleration was calculated from motion capture data. A total of 147 falls were analyzed.Results. The young group underwent 88 falls, in which 11.4% resulted in head impact. The older group underwent 59 falls, in which 34.5% resulted in head impact. A proportion analysis revealed older adults had a significantly greater proportion of head impacts than young adults (X2(1) = 11.445, p = 0.001). A two-way ANOVA only revealed a main effect of head impact on acceleration (F(1,142) = 54.342, p<0.001).Conclusion. The older adults experienced a greater proportion of head impacts during sideways falls. Head impact resulted in greater head acceleration compared to no head impact. Collectively, this data highlights the possibility that age-related neuromuscular changes to head control may result in elevated risk of fall-related TBIs. Future research examining mechanisms underlying increases in fall-related head impact is warranted.

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