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Updated: Mar 2, 2026
A Test Bed to Examine Helmet Fit and Retention and Biomechanical Measures of Head and Neck Injury in Simulated Impact
Published on: September 21, 2017
Development and validation of a physical model to investigate the biomechanics of infant head impact
Insights
Child head injuries are common, but understanding impact mechanics is limited. New research reveals localized accelerations can be triple the global average, highlighting critical regional vulnerabilities.
Area of Science:
- Biomechanics
- Pediatric Traumatology
- Injury Prevention
Background:
- Childhood head injuries are a leading cause of death and disability.
- Current understanding of pediatric head injury mechanics is limited, hindering diagnosis and prevention.
- Existing research relies on post-mortem human surrogate (PMHS) experiments using calculated global acceleration.
Purpose of the Study:
- To develop and validate a new experimental methodology for assessing regional head impact response in infants.
- To challenge the 'global approximation' of head injury vulnerability with localized data.
- To investigate the mechanics of infant head deformation and strain under impact.
Main Methods:
- A 3D-printed surrogate infant head was created using CT scans and validated against PMHS data.
- The surrogate brain was simulated using a gelatin/water mix.
- High-Speed Digital-Image-Correlation measured linear/angular velocities, accelerations, strains, and strain rates during impacts.
Main Results:
- Regional and local accelerations were up to three times greater than calculated 'global' accelerations.
- Impact location significantly influenced differential acceleration patterns.
- Sutures and fontanelles experienced ten times more strain than bone, leading to significant skull deformation.
- Perpendicular impacts generated greater rotational velocities and accelerations due to skull geometry changes.
Conclusions:
- The developed methodology provides crucial regional and local head impact data, improving understanding of infant head injury.
- Localized impact responses differ significantly from global approximations, necessitating revised injury assessment.
- Findings offer new insights for clinical diagnosis, forensic analysis, and the development of effective injury prevention strategies for children.
Abstract:
Head injury in childhood is the single most common cause of death or permanent disability from injury. However, despite its frequency and significance, there is little understanding of the response of a child's head to injurious loading. This is a significant limitation when making early diagnoses, informing clinical and/or forensic management or injury prevention strategies. With respect to impact vulnerability, current understanding is predominantly based on a few post-mortem-human-surrogate (PMHS) experiments. Researchers, out of experimental necessity, typically derive acceleration data, currently an established measure for head impact vulnerability, by calculation. Impact force is divided by the head mass, to produce a "global approximation", a single-generalised head response acceleration value. A need exists for a new experimental methodology, which can provide specific regional or localised response data. A surrogate infant head, was created from high resolution computer tomography scans with properties closely matched to tissue response data and validated against PMHS head impact acceleration data. The skull was 3D-printed from co-polymer materials. The brain, represented as a lumped mass, comprised of an injected gelatin/water mix. High-Speed Digital-Image-Correlation optically measured linear and angular velocities and accelerations, strains and strain rates. The "global approximation" was challenged by comparison with regional and local acceleration data. During impacts, perpendicular (at 90°) to a surface, regional and local accelerations were up to three times greater than the concomitant "global" accelerations. Differential acceleration patterns were very sensitive to impact location. Suture and fontanelle regions demonstrated ten times more strain (103%/s) than bone, resulting in skull deformations similar in magnitude to those observed during child birth, but at much higher rates. Surprisingly, perpendicular impacts produced significantly greater rotational velocities and accelerations, which are closer to current published injury thresholds than expected, seemingly as a result of deformational changes to the complex skull geometry. The methodology has proven a significant new step in characterising and understanding infant head injury mechanics.
