CT-based Model Reproduced Muskox Skull Vibrations During Experimental Validation

July 6, 2026

Research · Anatomy & morphology

A biomechanics study published online on 6 July 2026 built and experimentally tested the first finite-element model designed to reproduce the dynamic response of a muskox (Ovibos moschatus) skull. CT scans captured the skull’s internal geometry, while local bone density was used to assign different material stiffnesses throughout the model.

A finite-element model divides a complex structure into many small elements and calculates how each part responds to force. The validation experiment did not simulate an actual head-to-head collision. Instead, the researchers tested whether the digital skull could reproduce the vibration behaviour of the real specimen under controlled loading.

The skull was excited from 10 to 10,000 Hz

For the experimental test, the real skull was subjected to harmonic mechanical excitation across frequencies from 10 to 10,000 Hz. A scanning laser Doppler vibrometer measured how the surface moved on the left horn and on the nasal bone.

The same harmonic loading was simulated in the CT-based model. The researchers then compared experimental and numerical transfer functions — the relationship between the applied load and the resulting vibration velocity — as well as the skull’s natural frequencies, vibration mode shapes and phase response. Phase response describes the timing offset between the applied vibration and the skull’s resulting motion.

Horn and nasal bone showed different deformation patterns

The horn and nasal region did not behave as one rigid structure across the frequency range. Different resonances produced distinct mode shapes: characteristic patterns in which particular parts of the structure move together while other regions move less.

The nasal bone produced especially complex mode shapes, so the researchers matched measured resonance peaks with the corresponding simulated modes and compared the shifts in frequency. This allowed a more stringent comparison than simply checking whether peaks appeared at roughly the same frequencies.

Model and experiment agreed through several kilohertz

The authors report good agreement between measured and simulated transfer functions and mode shapes up to about 5 kHz. In their overall assessment, which also included phase response, they summarised the model as experimentally validated up to about 4 kHz.

The validation therefore covered both when the skull resonated and how the horn and nasal regions deformed during those resonances. The authors report that this extends experimental and numerical validation to a higher frequency range than previously achieved for finite-element models of other bovid skulls.

Bone density was built into the model

The CT data were also used for more than reconstructing the outer shape. The researchers assigned material properties according to local density, allowing the model to represent stiffness gradients within the skull rather than treating all bone as mechanically identical.

This density-based approach is established in medical bone modelling but had not previously been applied in this way to bovid skulls. It provides a route for studying how geometry and spatial differences in bone properties contribute to the skull’s dynamic response.

The validated model is a foundation for impact research

Muskox bulls repeatedly strike one another head-first during combat, making the skull a model system for research on structures that tolerate repeated high-energy loading. The broader research project aims to understand how skull geometry, bone architecture and material properties may contribute to impact mitigation.

This validation study establishes the numerical tool needed for that work. Its experimental test used controlled harmonic vibration rather than an actual collision, but showing that the model reproduces the real skull’s measured dynamics is a prerequisite before the same framework can be used to investigate more complex impact loading.

Sources and image credit

Foucher, C., Taenzer, L., Michler, J., Van Damme, B., Zysset, P. K., & Schwiedrzik, J. J. (2026). Dynamic response of the muskox head: Experimental validation of a CT-based finite element model using Scanning Laser Dopler Vibrometry. Journal of the Mechanical Behavior of Biomedical Materials, 182, 107534.Primary peer-reviewed study first available online 6 July 2026. A CT-based finite-element model was compared directly with scanning laser Doppler vibrometry measurements from the horn and nasal bone under harmonic excitation from 10 to 10,000 Hz. Transfer functions and mode shapes agreed well through several kilohertz; the authors report overall validation to about 4 kHz including phase response.
Max Planck Institute for Sustainable Materials. Multiscale investigation of impact mitigation strategies: Biomimicking muskox head.Project context used only to explain that the validated skull model forms part of a broader programme investigating how muskox head structures tolerate repeated impacts and how those principles may inform bio-inspired materials.

Image: Gregory Paul Smith — two adult muskox bulls head-butting, 1 June 2021; Wikimedia Commons / Flickr; CC BY-SA 2.0. Uncropped representative behaviour image, not the skull specimen used in the 2026 biomechanics study. · CC BY-SA 2.0 · Source

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