Background: This study investigated the role of the abductor digiti minimi (ADM) muscle on foot stability and how stress distribute across the plantar fascia, helping to understand better its involvement in conditions like plantar fasciitis or even ankle instability. Methods: A truss-based model and a 3D finite element model of the lateral side of foot were developed to analyze the biomechanical function of the ADM muscle. The geometry was constructed through segmentation of CT scans using 3D Slicer software, and then the model was processed and assembled in SolidWorks. The complete model was then imported into ANSYS for simulation process. The analysis highlighted how changing the ADM muscle force could be affecting the plantar fascia stress distribution and also the displacement in the fifth metatarsal bone, when 350 N of load was applied. Results: The truss-based model showed that strain increased from 0.013 mm/mm to 0.05 mm/mm, and stress increased from 4.5 MPa to 17.5 MPa with resection of ADM. Also, in the numerical 3D model, a 50% reduction in ADM pulling force led to a significant increase in plantar fascia stress, reaching 48.9 MPa, and a slight increase in axial displacement of the fifth metatarsal bone to 3.3 mm. These results suggested that the ADM muscle acts as a shock absorber, supporting the foot arch and limiting excessive plantar fascia loading. These results aligned with the previous observatory electromyograms and Magnetic Resonance Imaging studies, suggesting that decreased muscle function can increase stress on the plantar fascia, leading to plantar fasciitis and affect the fifth metatarsal bone displacement, contributing to ankle instability. Conclusion: This study highlighted the important role of the abductor digiti minimi muscle in foot stability and distributing mechanical loads during weight-bearing.
| Date of Award | 23 Sept 2025 |
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| Original language | English |
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| Supervisor | Naeem Mian (Main Supervisor) & Leigh Fleming (Co-Supervisor) |
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