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Direct in vivo quantification of the 3D talocrural and subtalar finite helical axes

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Thus, the purpose of this study was to non-invasively quantify the 3D in vivo finite helical axes (FHA) of the subtalar and talocrural joints... The 3D time dependent tibial, talar and calcaneal attitudes were quantified through integration of the velocity data... Yet the FHA was not oriented solely in the M-L direction and rotation of talocrural FHA with minimal displacement during PF was seen across all subjects... The subtalar FHA was directed primarily in the anterior-posterior direction (Figure 1B and 1D)... The amount of angulation in the M-L and superior-inferior directions varied during PF and was variable across subjects... The data from this study clearly confirmed that neither joint is a simple hinge joint and that ankle rotation arose primarily from the talocrural joint... The tendency of the subtalar and talocrural FHAs to rotate and translate will impact the calculation of tendon and ligament moment arms and, thus, alter the moment producing capabilities of the force generating structures at the ankle joint... Future modelling studies should investigate the sensitivity of the model outputs to variations in the FHA direction and location.

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FHAs for subject 9821R. All FHA's are plotted relative to the tibial coordinate system. The talocrural (subtalar) FHA changes from deep red (blue) to yellow (green) as the ankle plantarflexes. The length of the FHA indicates the magnitude of the angular velocity with the center of the line being the closest point the tibial origin (A&C) and talar origin (B&D). Ankle angle for this subject ranged from 1.9° to 39.4°.
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Figure 1: FHAs for subject 9821R. All FHA's are plotted relative to the tibial coordinate system. The talocrural (subtalar) FHA changes from deep red (blue) to yellow (green) as the ankle plantarflexes. The length of the FHA indicates the magnitude of the angular velocity with the center of the line being the closest point the tibial origin (A&C) and talar origin (B&D). Ankle angle for this subject ranged from 1.9° to 39.4°.

Mentions: The ratio of the talocrural to subtalar angular velocities varied greatly between subjects. This ratio ranged from 1.1 to 4.5. Talocrural joint rotation occurred primarily about the medial-lateral axis (Figure 1A and 1C) during plantar-flexion. Yet the FHA was not oriented solely in the M-L direction and rotation of talocrural FHA with minimal displacement during PF was seen across all subjects. The subtalar FHA was directed primarily in the anterior-posterior direction (Figure 1B and 1D). The amount of angulation in the M-L and superior-inferior directions varied during PF and was variable across subjects.


Direct in vivo quantification of the 3D talocrural and subtalar finite helical axes
FHAs for subject 9821R. All FHA's are plotted relative to the tibial coordinate system. The talocrural (subtalar) FHA changes from deep red (blue) to yellow (green) as the ankle plantarflexes. The length of the FHA indicates the magnitude of the angular velocity with the center of the line being the closest point the tibial origin (A&C) and talar origin (B&D). Ankle angle for this subject ranged from 1.9° to 39.4°.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2562116&req=5

Figure 1: FHAs for subject 9821R. All FHA's are plotted relative to the tibial coordinate system. The talocrural (subtalar) FHA changes from deep red (blue) to yellow (green) as the ankle plantarflexes. The length of the FHA indicates the magnitude of the angular velocity with the center of the line being the closest point the tibial origin (A&C) and talar origin (B&D). Ankle angle for this subject ranged from 1.9° to 39.4°.
Mentions: The ratio of the talocrural to subtalar angular velocities varied greatly between subjects. This ratio ranged from 1.1 to 4.5. Talocrural joint rotation occurred primarily about the medial-lateral axis (Figure 1A and 1C) during plantar-flexion. Yet the FHA was not oriented solely in the M-L direction and rotation of talocrural FHA with minimal displacement during PF was seen across all subjects. The subtalar FHA was directed primarily in the anterior-posterior direction (Figure 1B and 1D). The amount of angulation in the M-L and superior-inferior directions varied during PF and was variable across subjects.

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Thus, the purpose of this study was to non-invasively quantify the 3D in vivo finite helical axes (FHA) of the subtalar and talocrural joints... The 3D time dependent tibial, talar and calcaneal attitudes were quantified through integration of the velocity data... Yet the FHA was not oriented solely in the M-L direction and rotation of talocrural FHA with minimal displacement during PF was seen across all subjects... The subtalar FHA was directed primarily in the anterior-posterior direction (Figure 1B and 1D)... The amount of angulation in the M-L and superior-inferior directions varied during PF and was variable across subjects... The data from this study clearly confirmed that neither joint is a simple hinge joint and that ankle rotation arose primarily from the talocrural joint... The tendency of the subtalar and talocrural FHAs to rotate and translate will impact the calculation of tendon and ligament moment arms and, thus, alter the moment producing capabilities of the force generating structures at the ankle joint... Future modelling studies should investigate the sensitivity of the model outputs to variations in the FHA direction and location.

No MeSH data available.


Related in: MedlinePlus