Behind Amor Blunt Trauma Lung and Liver Strains From Indenter Loading Via Finite Element Modeling.

To determine behind armor blunt trauma (BABT) injury criteria, experiments have been conducted by launching blunt projectiles at live swine at velocities up to 65 meters per second (m/s) using one type of indenter design. To ensure the generalizability of the developed injury criteria, additional tests with different indenter designs are needed. The objectives of this study were to evaluate the kinematics and injury parameters from two indenter designs using human body finite element modeling.

Behind Armor Blunt Trauma: Liver Injuries Using a Live Animal Model.

Introduction: While the 44-mm clay penetration criterion was developed in the 1970s for soft body armor applications, and the researchers acknowledged the need to conduct additional tests, the same behind the armor blunt trauma displacement limit is used for both soft and hard body armor evaluations and design considerations. Because the human thoraco-abdominal contents are heterogeneous, have different skeletal coverage, and have different functional requirements, the same level of penetration limit does not imply the same level of protection. It is important to determine the regional responses of different thoraco-abdominal organs to better describe human tolerance and improve the current behind armor blunt trauma standard.

Direct Combat-related U.S. Army Aviation Injuries 2003-2014.

Introduction: The U.S. Army Aeromedical Research Laboratory (USAARL), a partner in the Joint Trauma Analysis for the Prevention of Injury in Combat (JTAPIC) partnership, conducted a series of retrospective reviews to investigate injuries sustained by occupants of U.

Analysis of Injury Metrics From Experimental Cardiac Injuries From Behind Armor Blunt Trauma Using Live Swine Tests: A Pilot Study.

Introduction: Warfighters are issued hard body armor designed to defeat ballistic projectiles. The resulting backface deformation can injure different thoracoabdominal organs. Developed over decades ago, the behind armor blunt impact criterion of maximum 44 mm depth in clay continues to be used independent of armor type or impact location on the thoracoabdominal region covered by the armor.

Preliminary Head-Supported Mass Performance Guidance for Dismounted Soldier Environments.

Introduction: The helmet is an ideal platform to mount technology that gives U.S. Soldiers an advantage over the enemy; the total system is recognized quantitatively as head-supported mass (HSM).

Head Flail Corridors From Sled Impact Acceleration Tests for Use in Occupant-Centric Vehicle Design.

Introduction: In aircraft crashes, injuries to the head and upper torso are frequently reported, with head injury reported most frequently of all body regions. Because preventing flail of the head and body is of utmost importance for occupant survival, the Aircraft Crash Survival Design Guide (ACSDG), the guide to crashworthy aircraft design, published flail envelopes. However, the ACSDG flail envelopes are based on a single test with an anthropomorphic test device subjected to a frontal acceleration.

Regional Strain Response of an Anatomically Accurate Human Finite Element Head Model Under Frontal Versus Lateral Loading.

Introduction: Because brain regions are responsible for specific functions, regional damage may cause specific, predictable symptoms. However, the existing brain injury criteria focus on whole brain response. This study developed and validated a detailed human brain computational model with sufficient fidelity to include regional components and demonstrate its feasibility to obtain region-specific brain strains under selected loading.

Strain Response of an Anatomically Accurate Nonhuman Primate Finite Element Brain Model Under Sagittal Loading.

Introduction: Prevention and treatment of traumatic brain injuries is critical to preserving soldier brain health. Laboratory studies are commonly used to reproduce injuries, understand injury mechanisms, and develop tolerance limits; however, this approach has limitations for studying brain injury, which requires a physiological response. The nonhuman primate (NHP) has been used as an effective model for investigating brain injury for many years.

A Biomechanical Investigation of Cervical Spine Range of Motion for UH-60 Aviators in Real and Simulated Flight Environments.

Introduction: Military flight surgeons evaluating aviators for flight fitness based on the cervical spine range of motion (CROM) have no operationally relevant reference with which to make a reliable determination. The published physiological limits for the general population do not necessarily apply to military aviators. CROM requirements for rotary-wing aviators would ideally be defined by measurements taken directly within their operational environment.

A Novel Paradigm to Develop Regional Thoracoabdominal Criteria for Behind Armor Blunt Trauma Based on Original Data.

Introduction: For behind armor blunt trauma (BABT), recent prominent BABT standards for chest plate define a maximum deformation distance of 44 mm in clay. It was developed for soft body armor applications with limited animal, gelatin, and clay tests. The legacy criterion does not account for differing regional thoracoabdominal tolerances to behind armor-induced injury.

Fracture Injury Risk of the Restrained Mandible to Anterior-Posterior Blunt Impacts.

This study describes the results of anterior-posterior impacts conducted on the mandibles of 22 male postmortem human subjects (PMHSs). The objective of this study was to develop an injury criterion for the mandible based on blunt impact while the jaw was restrained. Previous studies have attempted to characterize the injury risk of blunt impact to the mandible; however, due to the translation of the mandible during impact and a limited number of fractured specimens, previous studies were not able to produce an injury criterion.

Pelvic Injury Risk Curves for the Military Populations From Lateral Impact.

Introduction: Current methods for transporting military troops include nonstandard seating orientations, which may result in novel injuries because of different types/directions of loading impact. The objective of this study is to develop pelvic injury risk curves (IRCs) under lateral impacts from human cadaver tests using survival analysis for application to military populations.

Methods: Published data from lateral impacts applied to whole-body cadaver specimens were analyzed.

A Comparison of Nonhuman Primate Injuries in Horizontal Versus Vertical Sled +Gz (Head-to-Foot) Impact Accelerations.

Introduction: Accelerative events commonly expose military pilots to potentially injurious + Gz (axial, caudal to cranial) accelerations. The Naval Biodynamics Laboratory exposed nonhuman primates (NHPs) to + Gz loading in two subject orientations (supine or upright) to assess the effect of orientation and accelerations associated with injury at accelerations unsafe for human participation.

Materials And Methods: Archived care records, run records, and necropsy and pathology reports were used to identify acceleration-related injuries.

A Novel Application of Head Tracking Data in the Analysis and Assessment of Operational Cervical Spine Range of Motion for Army Aviators.

Introduction: Neck pain among rotary-wing aviators has been established as an important issue in the military community, yet no U.S. Army regulation defines exactly what cervical spine range of motion (CROM) is adequate for flight.

Mass Properties Comparison of Dismounted and Ground-Mounted Head-Supported Mass Configurations to Existing Performance and Acute Injury Risk Guidelines.

In order to limit the aviator's exposure to potentially unsafe helmet configurations, the U.S. Army Aeromedical Research Laboratory (USAARL) developed the USAARL Head-supported mass (HSM) Performance Curve and Acute Injury Risk Curve as guidelines for Army aviation HSM.

Retrospective Analysis of Injuries in Underbody Blast Events: 2007-2010.

Underbody Blast (UBB) exposure emerged as a substantial cause of morbidity and mortality of Service Members in Iraq and Afghanistan, which was unique to OIF/OEF due to the frequent use of improvised explosive devices. Improvised explosive devices under the vehicle delivered high-rate vertical loading to the vehicle translating energy to the occupant(s) resulting in injuries. Injury mitigating technologies needed to be developed; however, technologies rely on biomechanical human response data for research and development.

Preliminary Investigation of Skull Fracture Patterns Using an Impactor Representative of Helmet Back-Face Deformation.

Military combat helmets protect the wearer from a variety of battlefield threats, including projectiles. Helmet back-face deformation (BFD) is the result of the helmet defeating a projectile and deforming inward. Back-face deformation can result in localized blunt impacts to the head.

Evaluation of Environmental Sensors During Laboratory Direct and Indirect Head Exposures.

With the prevalence of traumatic brain injury (TBI) in the military and athletics, several commercial and military environmental sensors (ES) have been developed to quantify head impact exposures. The performance of five ES in controlled laboratory exposures from direct and indirect loadings, and the effect on impact protection and dynamic retention of the worn Advanced Combat Helmet (ACH) was evaluated. Direct impacts were conducted on a drop tower and indirect impacts used a mini-sled.

Initial analysis of archived non-human primate frontal and rear impact data from the biodynamics data resource.

Objective: The research objective was to conduct an initial analysis of non-human primate (NHP) data from frontal and rear impact events archived in the Biodynamics Data Resource (BDR) records of the Naval Biodynamics Laboratory (NBDL). These rare data, collected between 1973 and 1989, will inform the safety community of upper-end tolerance limits of NHP and may be related to severe crash scenarios.

Methods: Data from frontal and rear acceleration tests to 93 macaque NHP were examined.

Development of an injury risk curve for pelvic fracture in vertical loading environments.

Objective: Pelvis injury mechanisms are dependent upon loading direction (frontal, lateral, and vertical). Studies exist on the frontal and lateral modes; however, similar studies in the vertical mode are relatively sparse. Injury risk curves and response corridors are needed to delineate the biomechanical responses.

Characterization of the frequency and muscle responses of the lumbar and thoracic spines of seated volunteers during sinusoidal whole body vibration.

Whole body vibration has been postulated to contribute to the onset of back pain. However, little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to measure the frequency and corresponding muscle responses of seated male volunteers during whole body vibration exposures along the vertical and anteroposterior directions to define the transmissibility and associated muscle activation responses for relevant whole body vibration exposures.

Cervical spine injury biomechanics: Applications for under body blast loadings in military environments.

Background: While cervical spine injury biomechanics reviews in motor vehicle and sports environments are available, there is a paucity of studies in military loadings. This article presents an analysis on the biomechanics and applications of cervical spine injury research with an emphasis on human tolerance for underbody blast loadings in the military.

Methods: Following a brief review of published military studies on the occurrence and identification of field trauma, postmortem human subject investigations are described using whole body, intact head-neck complex, osteo-ligamentous cervical spine with head, subaxial cervical column, and isolated segments subjected to differing types of dynamic loadings (electrohydraulic and pendulum impact devices, free-fall drops).

A kinematic and anthropometric study of the upper cervical spine and the occipital condyles.

The center of rotation (COR) of the upper cervical spine (UCS) is an important biomechanical landmark that is used to determine upper neck moment, particularly when evaluating injury risk in the automotive environment. However, neither the location of the UCS CORs nor the occipital condyles (OCs), which are frequently the referenced landmark for UCS CORs, have been measured with respect to known cranial landmarks. This study determines the CORs using pure bending (+/-3.

Variation of neck muscle strength along the human cervical spine.

The aim of this study was to describe and explain the variation of neck muscle strength along the cervical spine. A three-dimensional model of the head-neck complex was developed to test the hypothesis that the moment-generating capacity of the neck musculature is lower in the upper cervical spine than in the lower cervical spine. The model calculations suggest that the neck muscles can protect the lower cervical spine from injury during extension and lateral bending.