Moment arms about the carpal and metacarpophalangeal joints for flexor and extensor muscles in equine forelimbs.
Abstract: To determine whether muscle moment arms at the carpal and metacarpophalangeal joints can be modeled as fixed-radius pulleys for the range of motion associated with the stance phase of the gait in equine forelimbs. Methods: 4 cadaveric forelimbs from 2 healthy Thoroughbreds. Methods: Thin wire cables were sutured at the musculotendinous junction of 9 forelimb muscles. The cables passed through eyelets at each muscle's origin, wrapped around single-turn potentiometers, and were loaded. Tendon excursions, measured as the changes in lengths of the cables, were recorded during manual rotation of the carpal (180 degrees to 70 degrees) and metacarpophalangeal (220 degrees to 110 degrees) joints. Extension of the metacarpophalangeal joint (180 degrees and 220 degrees) was forced with an independent loading frame. Joint angle was monitored with a calibrated potentiometer. Moment arms were calculated from the slopes of the muscle length versus joint angle curves. Results: At the metacarpophalangeal joint, digital flexor muscle moment arms changed in magnitude by < or = 38% during metacarpophalangeal joint extension. Extensor muscle moment arms at the carpal and metacarpophalangeal joints also varied (< or = 41% at the carpus) over the range of joint motion associated with the stance phase of the gait. Conclusions: Our findings suggest that, apart from the carpal flexor muscles, muscle moment arms in equine forelimbs cannot be modeled as fixed-radius pulleys. Assuming that muscle moment arms at the carpal and metacarpophalangeal joints have constant magnitudes may lead to erroneous estimates of muscle forces in equine forelimbs.
Publication Date: 2003-03-29 PubMed ID: 12661877DOI: 10.2460/ajvr.2003.64.351Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigates if muscle moment arms in the forelimbs of horses can be modeled as fixed-radius pulleys during the stance phase of their gait. The results indicate that, with the exception of the carpal flexor muscles, this is not possible and could lead to inaccurate estimations of muscle forces.
Methodology
- The study used four cadaveric forelimbs from two healthy Thoroughbreds.
- Thin wire cables were sutured at the musculotendinous junction of nine different forelimb muscles. These cables then passed through eyelets located at each muscle’s origin, were wrapped around potentiometers and then loaded.
- Tendon excursions were measured as changes in the length of the cables while the carpal and metacarpophalangeal joints were manually rotated. The specific angles for these rotations were 180 to 70 degrees for the carpal joint, and 220 to 110 degrees for the metacarpophalangeal joint.
- An independent loading frame was used to force the extension of the metacarpophalangeal joint (at 180 degrees and 220 degrees).
- A calibrated potentiometer was used to monitor the joint angles, and moment arms were calculated using the slopes of the muscle length versus joint angle curves.
Results
- The team discovered that the digital flexor muscle moment arms at the metacarpophalangeal joint experienced a magnitude change of less than or equal to 38% during the joint’s extension.
- The extensor muscle moment arms at both the carpal and metacarpophalangeal joints also changed significantly, to up to 41% at the carpus, across the range of joint motion related to the stance phase of the gait.
Conclusion
- These results suggest that muscle moment arms in equine forelimbs cannot be accurately modeled as fixed-radius pulleys, except for the carpal flexor muscles.
- This means that assuming constant magnitudes for muscle moment arms at the carpal and metacarpophalangeal joints can lead to incorrect estimations of muscle forces in the equine forelimb.
Cite This Article
APA
Brown NA, Pandy MG, Buford WL, Kawcak CE, McIlwraith CW.
(2003).
Moment arms about the carpal and metacarpophalangeal joints for flexor and extensor muscles in equine forelimbs.
Am J Vet Res, 64(3), 351-357.
https://doi.org/10.2460/ajvr.2003.64.351 Publication
Researcher Affiliations
- Department of Biomedical Engineering, College of Engineering, University of Texas, Austin, TX 78712, USA.
MeSH Terms
- Animals
- Cadaver
- Carpal Bones / anatomy & histology
- Carpal Bones / physiology
- Forelimb / anatomy & histology
- Forelimb / physiology
- Horses / anatomy & histology
- Horses / physiology
- Metacarpophalangeal Joint / anatomy & histology
- Metacarpophalangeal Joint / physiology
- Models, Anatomic
- Movement
- Muscle, Skeletal / anatomy & histology
- Muscle, Skeletal / physiology
Citations
This article has been cited 14 times.- Brocklehurst RJ, Fahn-Lai P, Regnault S, Pierce SE. Musculoskeletal modeling of sprawling and parasagittal forelimbs provides insight into synapsid postural transition. iScience 2022 Jan 21;25(1):103578.
- Wiseman ALA. Three-dimensional volumetric muscle reconstruction of the Australopithecus afarensis pelvis and limb, with estimations of limb leverage. R Soc Open Sci 2023 Jun;10(6):230356.
- Wiseman ALA, Bishop PJ, Demuth OE, Cuff AR, Michel KB, Hutchinson JR. Musculoskeletal modelling of the Nile crocodile (Crocodylus niloticus) hindlimb: Effects of limb posture on leverage during terrestrial locomotion. J Anat 2021 Aug;239(2):424-444.
- van Beesel J, Hutchinson JR, Hublin JJ, Melillo SM. Exploring the functional morphology of the Gorilla shoulder through musculoskeletal modelling. J Anat 2021 Jul;239(1):207-227.
- Heers AM, Rankin JW, Hutchinson JR. Building a Bird: Musculoskeletal Modeling and Simulation of Wing-Assisted Incline Running During Avian Ontogeny. Front Bioeng Biotechnol 2018;6:140.
- McHorse BK, Biewener AA, Pierce SE. Mechanics of evolutionary digit reduction in fossil horses (Equidae). Proc Biol Sci 2017 Aug 30;284(1861).
- Hutchinson JR, Rankin JW, Rubenson J, Rosenbluth KH, Siston RA, Delp SL. Musculoskeletal modelling of an ostrich (Struthio camelus) pelvic limb: influence of limb orientation on muscular capacity during locomotion. PeerJ 2015;3:e1001.
- Crook TC, Cruickshank SE, McGowan CM, Stubbs N, Wilson AM, Hodson-Tole E, Payne RC. A comparison of the moment arms of pelvic limb muscles in horses bred for acceleration (Quarter Horse) and endurance (Arab). J Anat 2010 Jul;217(1):26-37.
- Merritt JS, Davies HM, Burvill C, Pandy MG. Influence of muscle-tendon wrapping on calculations of joint reaction forces in the equine distal forelimb. J Biomed Biotechnol 2008;2008:165730.
- Smith NC, Payne RC, Jespers KJ, Wilson AM. Muscle moment arms of pelvic limb muscles of the ostrich (Struthio camelus). J Anat 2007 Sep;211(3):313-24.
- Williams SB, Payne RC, Wilson AM. Functional specialisation of the pelvic limb of the hare (Lepus europeus). J Anat 2007 Apr;210(4):472-90.
- Payne RC, Crompton RH, Isler K, Savage R, Vereecke EE, Günther MM, Thorpe SK, D'Août K. Morphological analysis of the hindlimb in apes and humans. II. Moment arms. J Anat 2006 Jun;208(6):725-42.
- Payne RC, Hutchinson JR, Robilliard JJ, Smith NC, Wilson AM. Functional specialisation of pelvic limb anatomy in horses (Equus caballus). J Anat 2005 Jun;206(6):557-74.
- Brown NA, Pandy MG, Kawcak CE, McIlwraith CW. Force- and moment-generating capacities of muscles in the distal forelimb of the horse. J Anat 2003 Jul;203(1):101-13.
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