Mechanical loading of the distal end of the third metacarpal bone in horses during walking and trotting.
OBJECTIVE
To assess the net mechanical load on the distal end of the third metacarpal bone in horses during walking and trotting.


METHODS
3 Quarter Horses and 1 Thoroughbred.


METHODS
Surface strains measured on the left third metacarpal bone of the Thorough-bred were used with a subject-specific model to calculate loading (axial compression, bending, and torsion) of the structure during walking and trotting. Forelimb kinematics and ground reaction forces measured in the 3 Quarter Horses were used with a musculoskeletal model of the distal portion of the forelimb to determine loading of the distal end of the third metacarpal bone.


RESULTS
Both methods yielded consistent data regarding mechanical loading of the distal end of the third metacarpal bone. During walking and trotting, the distal end of the third metacarpal bone was loaded primarily in axial compression as a result of the sum of forces exerted on the metacarpal condyles by the proximal phalanx and proximal sesamoid bones.


CONCLUSIONS
Results of strain gauge and kinematic analyses indicated that the major structures of the distal portion of the forelimb in horses acted to load the distal end of the third metacarpal bone in axial compression throughout the stance phase of the stride.
Merritt
Jonathan S
JS
Department of Mechanical Engineering, School of Engineering, University of Melbourne, Melbourne, VIC 3010, Australia. merritt@unimelb.edu.au
Pandy
Marcus G
MG
Brown
Nicholas A T
NA
Burvill
Colin R
CR
Kawcak
Christopher E
CE
McIlwraith
C Wayne
CW
Davies
Helen M S
HM
D000818:Animals; D001696:Biomechanical Phenomena; D005552:Forelimb / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D050279:Metacarpal Bones / Q000502:physiology*; D011187:Posture; D012420:Running / Q000502:physiology*; D013314:Stress, Mechanical; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing