scholarly journals High-Rate Anisotropic Properties in Human Infant Parietal and Occipital Bone

2021 ◽  
Author(s):  
Robert M. Metcalf ◽  
Jessica Comstock ◽  
Brittany Coats
Keyword(s):  
Head Injury ◽  
Material Property ◽  
Fiber Orientation ◽  
Head Impact ◽  
High Rate ◽  
Human Infant ◽  
Cranial Bone ◽  
Anisotropic Properties ◽  
Bending Modulus ◽  
Property Data

Abstract Computational models of infant head impact are limited by the paucity of infant cranial bone material property data, particularly with regards to the anisotropic relationships created by the trabecular fibers in infant bone. We previously reported high-rate material property data for human infant cranial bone tested perpendicular to trabeculae fiber orientation. In this study we measure the anisotropic properties of human infant cranial bone by analyzing bending modulus parallel to the trabeculae fibers. We tested human bone specimens from 9 donors ranging in age from 32 weeks gestational age to 10 months of age at strain rates 12.3-30.1 s^(-1). Bending modulus significantly increased with donor age (p=0.008), and was 13.4 times greater along the fiber direction compared to perpendicular to the fibers. Ultimate stress was greater by 5.1 times when tested parallel to the compared to perpendicular (p=0.067). Parietal bone had a higher modulus and ultimate stress compared to occipital bone, but this trend was not significant, as previously shown perpendicular to fiber orientation. Combined, these data suggest the pediatric skull is highly age-dependent, anisotropic, and regionally dependent. The incorporation of these characteristics in finite element models of infant head impact will be necessary to advance pediatric head injury research, and further our understanding of the mechanisms of head injury in children.

Infant Skull and Suture Properties: Measurements and Implications for Mechanisms of Pediatric Brain Injury

2000 ◽  
Vol 122 (4) ◽  
pp. 364-371 ◽  
Author(s):  
Susan S. Margulies ◽  
Kirk L. Thibault
Keyword(s):  
Elastic Modulus ◽  
Head Injury ◽  
Ultimate Stress ◽  
Human Infant ◽  
Cranial Bone ◽  
Published Data ◽  
Deformation Pattern ◽  
Three Point Bending ◽  
Adult Human ◽  
Bone Properties

The mechanical properties of the adult human skull are well documented, but little information is available for the infant skull. To determine the age-dependent changes in skull properties, we tested human and porcine infant cranial bone in three-point bending. The measurement of elastic modulus in the human and porcine infant cranial bone agrees with and extends previous published data [McPherson, G. K., and Kriewall, T. J. (1980), J. Biomech., 13, pp. 9–16] for human infant cranial bone. After confirming that the porcine and human cranial bone properties were comparable, additional tensile and three-point bending studies were conducted on porcine cranial bone and suture. Comparisons of the porcine infant data with previously published adult human data demonstrate that the elastic modulus, ultimate stress, and energy absorbed to failure increase, and the ultimate strain decreases with age for cranial bone. Likewise, we conclude that the elastic modulus, ultimate stress, and energy absorbed to failure increase with age for sutures. We constructed two finite element models of an idealized one-month old infant head, one with pediatric and the other adult skull properties, and subjected them to impact loading to investigate the contribution of the cranial bone properties on the intracranial tissue deformation pattern. The computational simulations demonstrate that the comparatively compliant skull and membranous suture properties of the infant brain case are associated with large cranial shape changes, and a more diffuse pattern of brain distortion than when the skull takes on adult properties. These studies are a fundamental initial step in predicting the unique mechanical response of the pediatric skull to traumatic loads associated with head injury and, thus, for defining head injury thresholds for children. [S0148-0731(00)00904-3]

The European Union Mg-Engine Project - Generation of Material Property Data for Four Die Cast Mg-Alloys

2006 ◽  
Author(s):  
Per Bakke ◽  
Andreas Fischersworring-Bunk ◽  
Isabelle de Lima ◽  
Hans Lilholt ◽  
Ingemar Bertilsson ◽  
...  
Keyword(s):  
European Union ◽  
Material Property ◽  
Mg Alloys ◽  
The European Union ◽  
Property Data ◽  
Die Cast ◽  
Material Property Data

scholarly journals Favourable Outcome in Pediatric Neurosurgery for Extra Dural Hematoma in Sub Sahara Africa: Report of Parakou University Hospital in the Benin Republic

2020 ◽  
Vol 3 (3) ◽  
pp. 17-26
Author(s):  
Quenum K ◽  
Fatigba Oh ◽  
Houndje Yp ◽  
Tchegnonsi C ◽  
Alihonou T ◽  
...  
Keyword(s):  
Head Injury ◽  
Dura Mater ◽  
Road Traffic ◽  
Pediatric Neurosurgery ◽  
Favourable Outcome ◽  
University Hospital ◽  
Cranial Bone ◽  
Blood Collection ◽  
Cross Sectional ◽  
Surgical Department

Introduction The extra dural hematoma is a blood collection between the cranial vault and the dura mater. It is a neurosurgical emergency whose statistical data are poorly known in the Republic of Benin. Objective The aims of this study are to assess epidemiology, therapeutic and outcome of traumatic extra dural hematomas for children admitted to the surgical department of CHUD-B/A from 2012 to 2017. Methods This was a cross-sectional, descriptive and retrospective study over a period from January 1st, 2012 to December 31st, 2017. Results One hundred and seventy-eight cases of children aged between 0-15 years were examined for brain traumatic injury. Twenty-seven 27 (15.2%) cases of extra dural hematomas were retained. The most represented age group was between 11-15 years with a frequency of 42.1%. The male sex was more represented (78.9%). Road traffic accidents were the main aetiology (57.9%). 52.6% had a mild head injury, 26.3% had a moderate head injury and 21.1% had a severe head injury. On brain scan the frequently observed location was temporo-parietal (31.6%). Acute anemia was observed in 16 children. Seventeen children were operated on. The operation involved evacuation of extra dural hematoma by cranial bone flap with suspension of the dura mater. There were no deaths. Conclusion The availability of brain CT makes the diagnosis of extra dural hematoma easier. Its management is neurosurgical with a favourable post-operative evolution in all cases in this series.

Design and Validation of a Component Head Injury Criteria Tester for Aerospace Applications

2005 ◽  
Author(s):  
Hamid M. Lankarani ◽  
C. S. Koshy ◽  
C. K. Thorbole
Keyword(s):  
Head Injury ◽  
Seat Belt ◽  
Impact Angle ◽  
Head Impact ◽  
Aircraft Cabins ◽  
Aerospace Applications ◽  
Injury Criteria ◽  
Test Conditions ◽  
Head Injury Criteria ◽  
Impact Events

The compliance with Head Injury Criteria (HIC) specified in 14 CFR 23.562 [1] and CFR 25.562 [2] poses a significant problem for many segments of the aerospace industry. The airlines and the manufacturers of jet transports have made claims of high costs and significant schedule overruns during the development and certification of 16G seats because of the difficulties encountered in meeting this requirement. The current practice is to conduct Full Scale Sled Tests (FSST) on impact sleds. This approach can be expensive, since a new seat may be needed for each test. Moreover, some consider the HIC sensitive to changes in the test conditions, such as sled pulse, seat belt elongation, etc., resulting in HIC results from FSSTs showing poor repeatability. These difficulties make it desirable to devise a cheaper, faster, and more repeatable alternative to FSSTs. This paper describes an attempt to address these issues by designing a device, the National Institute for Aviation Research (NIAR) HIC Component Tester (NHCT) using various multibody tools. This device was then fabricated and its performance evaluated against FSSTs conducted under similar test conditions for some typical impact events that occur in an aircraft cabins e.g. impact with bulkheads. The factors compared for this evaluation are the head impact angle, head impact velocity, HIC, HIC window, peak head C.G. resultant acceleration, average head C.G. resultant acceleration, and head C.G. resultant acceleration profiles. The results of these evaluations show that the NHCT already produces test results that correlate significantly with FSST results for impact targets such as bulkheads and its target envelope is expected eventually to include objects such as seat backs.

scholarly journals Impact test comparisons of 20th and 21st century American football helmets

2012 ◽  
Vol 116 (1) ◽  
pp. 222-233 ◽  
Author(s):  
Adam Bartsch ◽  
Edward Benzel ◽  
Vincent Miele ◽  
Vikas Prakash
Keyword(s):  
Head Injury ◽  
21St Century ◽  
Injury Risk ◽  
Diffuse Axonal Injury ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Severity Index ◽  
Head Impact ◽  
American Football ◽  
Acute Subdural Hematoma

Object Concussion is the signature American football injury of the 21st century. Modern varsity helmets, as compared with vintage leather helmets, or “leatherheads,” are widely believed to universally improve protection by reducing head impact doses and head injury risk for the 3 million young football players in the US. The object of this study was to compare the head impact doses and injury risks with 11 widely used 21st century varsity helmets and 2 early 20th century leatherheads and to hypothesize what the results might mean for children wearing similar varsity helmets. Methods In an injury biomechanics laboratory, the authors conducted front, oblique front, lateral, oblique rear, and rear head impact tests at 5.0 m/second using helmeted headforms, inducing near- and subconcussive head impact doses on par with approximately the 95th percentile of on-field collision severity. They also calculated impact dose injury risk parameters common to laboratory and on-field traumatic neuromechanics: linear acceleration, angular acceleration, angular velocity, Gadd Severity Index, diffuse axonal injury, acute subdural hematoma, and brain contusion. Results In many instances the head impact doses and head injury risks while wearing vintage leatherheads were comparable to or better than those while wearing several widely used 21st century varsity helmets. Conclusions The authors do not advocate reverting to leather headgear, but they do strongly recommend, especially for young players, instituting helmet safety designs and testing standards, which encourage the minimization of linear and angular impact doses and injury risks in near- and subconcussive head impacts.

Analysis of a Multi-Layered Spherical Head Impact Model

1974 ◽  
Vol 96 (2) ◽  
pp. 534-540 ◽  
Author(s):  
S. L. Gordon ◽  
G. D. Moskowitz ◽  
R. Byers
Keyword(s):  
Head Injury ◽  
Head Impact ◽  
Solution Technique ◽  
Impact Model ◽  
Elastic Plastic ◽  
Skull Model ◽  
Spherical Head ◽  
Energy Absorbing ◽  
The Brain

The development of adequate protection against head injury requires a thorough knowledge of the mechanics of trauma to an unprotected head. Impact to multi-layered spherical head models are analyzed with an elastic skull, elastic tables and elastic-plastic diploe skull, and elastic tables and crushable foam diploe skull. All models have a hydrodynamic brain model. The energy absorbing skull models yield highly attenuated and smoothed tensile pressure peaks in the brain as compared to the elastic skull model. The generality of the solution technique would readily permit extension of the analyses to investigate impact to a head protected by a multi-layered helmet.

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