Infants and children in the adult world of automobile safety design: Pediatric and anatomical considerations for design of child restraints

doi:10.1016/0021-9290(69)90083-9

Journal of Biomechanics

Volume 2, Issue 3, July 1969, Pages 267-280

https://doi.org/10.1016/0021-9290(69)90083-9 Get rights and content

Abstract

The infant and child differ structurally from the adult in a number of ways which are critical to the design for protection against impact forces and for adequate occupant restraint systems. The purpose of this paper is to bring together a profile of the anatomy, anthropometry, growth, and development of the infant and child. Age differences related to the proper design of child restraint systems are emphasized. Problems discussed include child-adult structural differences, center of gravity of the body, the head mass in relation to the neck and general body proportions, positions of key organs, and biomechanical properties of tissues.

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Estimation of a statistical geometric model for the cervical vertebrae of children aged 10–18 years
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Citation Excerpt :
Child neck injuries in motor vehicle crashes (MVCs) result in high morbidity and mortality rates [1,2]. It is known that a child's neck is not simply a miniature version of an adult's neck [3]. Some anatomical structures of a child's cervical spine do not exist in an adult, or are undergoing noticeable changes.
Child neck injuries in motor vehicle crashes (MVCs) result in high morbidity and mortality rates. Estimating a statistical cervical vertebrae geometric model and quantifying the variations of the size and shape with age are very important for investigating the dynamic response and injury risk to a child's cervical spine, as well as for providing a geometric basis for developing child anthropomorphic test devices (ATDs) and finite element models (FEMs) of different ages. In this study, spatial geometric points were automatically extracted from the cervical vertebrae computed tomography (CT) scans of 30 children aged 10 to 18 years old (YO), and a statistical geometric model was estimated for the cervical vertebrae as a function of age and neck circumference/neck length according to the method of principal component analysis and regression (PCA&R). Based on this statistical model, geometric point sets representing cervical vertebrae geometries at different ages and percentiles were generated and formed to envelope surfaces. Meanwhile, the size changes of the cervical vertebrae with child growth from 10 to 18 YO were quantified. In general, the anteroposterior length (APL), transverse process width (TPW), vertebral body height (VBH), and vertebral body depth (VBD) of the cervical vertebrae increase with age; the VBH and VBD increase faster than the APL and TPW. Compared with other vertebrae, the APL of C7 is larger, and the rate of increase of C1 with age is evidently slower. The TPWs of C1 and C7 are greater than those of C2 to C6. C7 has higher average values for the VBH and VBD than C3 to C6.
Traditional and 3D scan extracted measurements of the heads and faces of Dutch children
2019, International Journal of Industrial Ergonomics
Citation Excerpt :
Firstly, the age composition within each age category could differ for each dataset which could influence the results. The dimensions of the face experience the most growth of the entire head, with rapid growth phases occurring mostly between the ages of 6 months and 4 years (Farkas et al., 1992; Burdi et al., 1969). As a result, having more children with an age between 12 and 18 months in age group 1 (that runs from 12 months to 24 months), for example, could result in smaller average values.
3D anthropometry has created a significant opportunity for designers to improve fit by offering detailed information regarding the shape of the human body. Various researchers have shown the benefit of using 3D anthropometric data in the development or evaluation of head related products for adults. However, detailed 3D anthropometric data of children heads and faces is still lacking. This paper presents up to date descriptive statistics of detailed measurements made of heads and faces of Dutch children. For the purpose of developing ergonomic head and face wear for children, an anthropometric survey was conducted, whereby children aged 6 months to 7 years were measured, utilising both traditional anthropometric measurement techniques and 3D image derived measurements. The traditional measurements were compared with the most recent dataset of Dutch children and, on a more detailed level, with a dataset of North American children.
A coupled physical-computational methodology for the investigation of short fall related infant head impact injury
2019, Forensic Science International
Citation Excerpt :
There was no variation in local impact acceleration response greater than 15%, that is, at the impact velocity of 1.72 m s−1, 11% at the vertex, 4% at the occiput, 6% at the frontal and 13% at the parietal regions and at the impact velocity of 2.43 m s−1by 12% (vertex), 3% (occiput), 5% frontal and 11% at the parietal region. As discussed above, this is unsurprising, since the mass of the infant skull bones is relatively small compared with to the overall mass of the head [28]. The bones are, therefore, likely to come to rest more quickly than the more massive structure of the brain.
Head injury in childhood is the most common cause of death or permanent disability from injury. However, insufficient understanding exists of the response of a child’s head to injurious loading scenarios to establish cause and effect relationships to assist forensic and safetly investigations. Largely as a result of a lack of availability of paediatric clinical and Post-Mortem-Human-Surrogate (PMHS) experimental data, a new approach to infant head injury experimentation has been developed. A coupled-methodology, combining a physical infant head surrogate, producing “real world” global, regional and localised impact response data and a computational Finite-Element (FE-head) model was created and validated against available PMHS and physical model global impact response data. Experimental impact simulations were performed to investigate regional and localised injury vulnerability. Different regions of the head produced accelerations significantly greater than those calculated using the currently available method of measuring the global, whole head response. The majority of material strain was produced within the relatively elastic suture and fontanelle regions, rather than the skull bones. A subsequent parametric analysis was conducted to provide a correlation between fall height and areas of maximum-stress-response and fracture-risk-probability. The FE-head was further applied to investigating fracture risk, simulating injurious PMHS impacts and a good qualitative match was observed. The FE-head shows significant potential for the study of infant head injury and is anticipated to be a motivating tool for the improvement of head injury understanding across a range of potentially injurious head loading scenarios.
Current playground surface test standards underestimate brain injury risk for children
2019, Journal of Biomechanics
Citation Excerpt :
All age groups of children from 0 to 18 YO are injured in playground accidents (Adelson et al., 2018; Wang et al., 2013) but a higher proportion of head and neck injuries are found among the youngest individuals (Adelson et al., 2018). The difference in anatomy between a young child compared to young adult is large, especially the head with softer skull bone with sutures as well as a higher ratio between head and body mass for the youngest children (Burdi et al., 1969). The usage of FE models of human body has increased during the last decades in the automotive industry as an important tool to evaluate and improve safety.
Playgrounds surface test standards have been introduced to reduce the number of fatal and severe injuries. However, these test standards have several simplifications to make it practical, robust and cost-effective, such as the head is represented with a hemisphere, only the linear kinematics is evaluated and the body is excluded. Little is known about how these simplifications may influence the test results. The objective of this study was to evaluate the effect of these simplifications on global head kinematics and head injury prediction for different age groups. The finite element human body model PIPER was used and scaled to seven different age groups from 1.5 up to 18 years old, and each model was impacted at three different playground surface stiffness and three head impact locations. All simulations were performed in pairs, including and excluding the body. Linear kinematics and skull bone stress showed small influence if excluding the body while head angular kinematics and brain tissue strain were underestimated by the same simplification. The predicted performance of the three different playground surface materials, in terms of head angular kinematics and brain tissue strain, was also altered when including the body. A body and biofidelic neck need to be included, together with suitable head angular kinematics based injury thresholds, in future physical or virtual playground surface test standards to better prevent brain injuries.
Effect of pediatric growth on cervical spine kinematics and deformations in automotive crashes
2018, Journal of Biomechanics
Citation Excerpt :
The availability of studies on the biomechanics of the pediatric cervical spine is more limited. It is however well known that there are large proportional and structural differences between children and adults (Burdi et al., 1969). Among children, the head is proportionally significantly larger in relation to the rest of the body compared to adults and the neck also becomes more slender with age.
Finite element (FE) models are a powerful tool that can be used to understand injury mechanisms and develop better safety systems. This study aims to extend the understanding of pediatric spine biomechanics, where there is a paucity of studies available. A newly developed and continuously scalable FE model was validated and scaled to 1.5-, 3-, 6-, 10-, 14- and 18-year-old using a non-linear scaling technique, accounting for local topological changes. The oldest and youngest ages were also scaled using homogeneous geometric scaling. To study the effect of pediatric spinal growth on head kinematics and intervertebral disc strain, the models were exerted to 3.5 g acceleration pulse at the T1 vertebra to simulate frontal, rear and side impacts. It was shown that the head rotation increases with age, but is over predicted when geometrically scaling down from 18- to 1.5-year-old and under predicted when geometrically scaling up from 1.5- to 18-year-old. The strain in the disc, however, showed a clear decrease with age in side impact and for the upper cervical spine in rear impact, indicating a higher susceptibility for neck injury at younger ages. In the frontal impact, no clear age dependence could be seen, suggesting a large contribution from changed facet joint angles, and lower levels of strain, suggesting a lower risk of injury. The results also highlight the benefit of rearward facing children in a seat limiting head lateral motion.
Effectiveness of the Load Legs in Enhancing the Passive Safety of Rear-Facing Child Seats in Frontal Crash
2024, SAE Technical Papers

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^☆: Presented at the ASME Third Biomechanical and Human Factors Division Conference at the University of Michigan, Ann Arbor, June 12–13, 1969.

View full text

Infants and children in the adult world of automobile safety design: Pediatric and anatomical considerations for design of child restraints☆

Abstract

J. Biomechanics

Study on the strength of human urinary organs

J. Kyoto Pref. Univ. Med.

Tensile strength of fetal and adult human tendons

School Health Problems

Impact injuries in pregnancy — I. Experimental studies

Am. J. Obstet. Gynec.

Blunt abdominal trauma

J. Trauma

Stress and Strain in Bones

Acute trauma in infants and children

What is known about the physiology of large blood vessels

Age changes of the strength for tension of human gastric walls

J. Kyoto Pref. Univ. Med.

Studies on the strength for bursting the walls of human and animal oesophages

J. Kyoto Pref. Univ. Med.

Biomechanics

Appl. Mech. Rev.

Mechanics of bone fracture

Studies on some physical properties of infant compact bone

Acta orthop. scand.

Radiographic Anatomy of The Human Skeleton

Studies on the strength of human skeletal muscles

J. Kyoto Pref. Univ. Med.

Head Injuries in Automobile Accidents Related to Seat, Position, and Age

The tension test upon the costal cartilage of a human body

J. Kyoto Pref. Univ. Med.

On the mechanical properties and behavior of human compact bone

Height, weight and body growth of American white and American negro boys at Philadelphia, aged 6–14 yr

Growth of man

The physical growth of Philadelphia white children, age 7–17 yr

The design and development of a more effective child restraint concept

Automotive cardio-thoracic injuries: a medico-engineering analysis

The functional body measurements of school age children