Force‐ and moment‐generating capacities of muscles in the distal forelimb of the horse

A detailed musculoskeletal model of the distal equine forelimb was developed to study the influence of musculoskeletal geometry (i.e. muscle paths) and muscle physiology (i.e. force–length properties) on the force‐ and moment‐generating capacities of muscles crossing the carpal and metacarpophalangeal joints. The distal forelimb skeleton was represented as a five degree‐of‐freedom kinematic linkage comprised of eight bones (humerus, radius and ulna combined, proximal carpus, distal carpus, metacarpus, proximal phalanx, intermediate phalanx and distal phalanx) and seven joints (elbow, radiocarpal, intercarpal, carpometacarpal, metacarpophalangeal (MCP), proximal interphalangeal (pastern) and distal interphalangeal (coffin)). Bone surfaces were reconstructed from computed tomography scans obtained from the left forelimb of a Thoroughbred horse. The model was actuated by nine muscle–tendon units. Each unit was represented as a three‐element Hill‐type muscle in series with an elastic tendon. Architectural parameters specifying the force‐producing properties of each muscle–tendon unit were found by dissecting seven forelimbs from five Thoroughbred horses. Maximum isometric moments were calculated for a wide range of joint angles by fully activating the extensor and flexor muscles crossing the carpus and MCP joint. Peak isometric moments generated by the flexor muscles were an order of magnitude greater than those generated by the extensor muscles at both the carpus and the MCP joint. For each flexor muscle in the model, the shape of the maximum isometric joint moment–angle curve was dominated by the variation in muscle force. By contrast, the moment–angle curves for the muscles that extend the MCP joint were determined mainly by the variation in muscle moment arms. The suspensory and check ligaments contributed more than half of the total support moment developed about the MCP joint in the model. When combined with appropriate in vivo measurements of joint kinematics and ground‐reaction forces, the model may be used to determine muscle–tendon and joint–reaction forces generated during gait.

[1]  A. J. van den Bogert,et al.  In vivo tendon forces in the forelimb of ponies at the walk, validated by ground reaction force measurements. , 1993, Acta anatomica.

[2]  A J van den Bogert,et al.  Model formulation and determination of in vitro parameters of a noninvasive method to calculate flexor tendon forces in the equine forelimb. , 2001, American journal of veterinary research.

[3]  K. T. Gibson,et al.  Effects of superior check desmotomy on flexor tendon and suspensory ligament strain in equine cadaver limbs. , 2001, Veterinary surgery : VS.

[4]  A J van den Bogert,et al.  Kinetics and kinematics of the equine hind limb: in vivo tendon strain and joint kinematics. , 1988, American journal of veterinary research.

[5]  M. Pandy.  Moment arm of a muscle force. , 1999, Exercise and sport sciences reviews.

[6]  Atlas of Equine Anatomy , 1991 .

[7]  R. M. Alexander,et al.  Elastic mechanisms in animal movement , 1988 .

[8]  A J van den Bogert,et al.  A kinematic and strain gauge study of the reciprocal apparatus in the equine hind limb. , 1992, Journal of biomechanics.

[9]  Alan M. Wilson,et al.  Horses damp the spring in their step , 2001, Nature.

[10]  A J van den Bogert,et al.  Mechanical properties of the tendinous equine interosseus muscle are affected by in vivo transducer implantation. , 1998, Journal of biomechanics.

[11]  S P James,et al.  The role of subchondral bone in joint disease: a review. , 2010, Equine veterinary journal.

[12]  N. Langrana,et al.  Locomotion in the horse: kinematics and external and internal forces in the normal equine digit in the walk and trot. , 1978, American journal of veterinary research.

[13]  D. Bartel,et al.  Locomotion in the horse: a procedure for computing the internal forces in the digit. , 1978, American journal of veterinary research.

[14]  H C Schamhardt,et al.  Joint moments and power in equine gait: a preliminary study. , 2010, Equine veterinary journal. Supplement.

[15]  A. J. van den Bogert,et al.  Tendon strain in the forelimbs as a function of gait and ground characteristics and in vitro limb loading in ponies. , 1996, Equine veterinary journal.

[16]  H C Schamhardt,et al.  Net joint moments and powers in the equine forelimb during the stance phase of the trot. , 1998, Equine veterinary journal.

[17]  D H Leach,et al.  Instant centres of rotation of equine limb joints and their relationship to standard skin marker locations. , 2010, Equine veterinary journal. Supplement.

[18]  A. J. van den Bogert,et al.  Quantitative analysis of computer-averaged electromyographic profiles of intrinsic limb muscles in ponies at the walk. , 1992, American journal of veterinary research.

[19]  D. W. Milne,et al.  In vivo and in vitro measurement of tendon strain in the horse. , 1980, American journal of veterinary research.

[20]  H C Schamhardt,et al.  Forelimb joint moments and power during the walking stance phase of horses. , 1998, American journal of veterinary research.

[21]  J Philipsson,et al.  Variation in conformation of Swedish warmblood horses and conformational characteristics of élite sport horses. , 1990, Equine veterinary journal.

[22]  Bartel Dl,et al.  Locomotion in the horse: a procedure for computing the internal forces in the digit. , 1978 .

[23]  A Barneveld,et al.  The effect of orthopaedic shoeing on the force exerted by the deep digital flexor tendon on the navicular bone in horses. , 1999, Equine veterinary journal.

[24]  A. Biewener,et al.  Muscle-tendon stresses and elastic energy storage during locomotion in the horse. , 1998, Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology.

[25]  F. Zajac.  Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. , 1989, Critical reviews in biomedical engineering.

[26]  J L Lanovaz,et al.  Sensitivity analysis and application to trotting of a noninvasive method to calculate flexor tendon forces in the equine forelimb. , 2001, American journal of veterinary research.

[27]  M. Pandy.  4 Moment A r m of a Muscle Force , 1999 .

[28]  M G Pandy,et al.  Computer modeling and simulation of human movement. , 2001, Annual review of biomedical engineering.

[29]  H. Schamhardt,et al.  Forelimb tendon loading during jump landings and the influence of fence height. , 2001, Equine veterinary journal. Supplement.

[30]  J. Hermanson,et al.  Four forearm flexor muscles of the horse, Equus caballus: Anatomy and histochemistry , 1992, Journal of morphology.

[31]  S. Woo,et al.  The Effects of a Popliteus Muscle Load on In Situ Forces in the Posterior Cruciate Ligament and on Knee Kinematics , 1998, The American journal of sports medicine.

[32]  M. Pandy,et al.  Architectural properties of distal forelimb muscles in horses, Equus caballus , 2003, Journal of morphology.

[33]  J. Lanovaz,et al.  The hindlimb in walking horses: 2. Net joint moments and joint powers , 2000 .

[34]  P. R. van Weeren,et al.  Effects of exercise on biomechanical properties of the superficial digital flexor tendon in foals. , 2001, American journal of veterinary research.

[35]  J. Denoix,et al.  Functional anatomy of tendons and ligaments in the distal limbs (manus and pes). , 1994, The Veterinary clinics of North America. Equine practice.

[36]  Marcus G Pandy,et al.  Moment arms about the carpal and metacarpophalangeal joints for flexor and extensor muscles in equine forelimbs. , 2003, American journal of veterinary research.

[37]  J. Hermanson.  Architecture and the division of labor in the extensor carpi radialis muscle of horses. , 1997, Acta anatomica.

[38]  Strain of the musculus interosseus medius and its rami extensorii in the horse, deduced from in vivo kinematics. , 1993, Acta anatomica.

[39]  M. P. Mcguigan,et al.  The force and contact stress on the navicular bone during trot locomotion in sound horses and horses with navicular disease. , 2010, Equine veterinary journal.

[40]  M. Butcher,et al.  Fetlock joint kinematics differ with age in thoroughbred racehorses , 2002 .

[41]  J. Lanovaz,et al.  The forelimb in walking horses: 1. Kinematics and ground reaction forces. , 2000, Equine veterinary journal.

[42]  Spurgeon Tl,et al.  Histochemical staining characteristics of normal horse skeletal muscle. , 1986 .