The musculoskeletal system in horses encompasses the bones, muscles, tendons, ligaments, and joints that facilitate movement and provide structural support. This system is essential for locomotion, athletic performance, and overall health in equine species. The equine skeleton consists of approximately 205 bones, which are connected by joints and supported by a network of muscles and connective tissues. Tendons connect muscles to bones, while ligaments link bones to other bones, contributing to joint stability. The musculoskeletal system is subject to various conditions, including injuries, degenerative diseases, and developmental disorders, which can impact a horse's mobility and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, pathology, and treatment of musculoskeletal conditions in horses.
Rivero JL, Serrano AL, Quiroz-Rothe E, Aguilera-Tejero E.The objective of this study was to investigate the relationship between kinematic variables and muscle characteristics by determining (1) if heavy endurance training alters these variables and (2) if such modifications occur in a coordinated manner. Fifteen Andalusian stallions age 41-45 months were used. Five horses were used as controls and 10 horses underwent a training programme based on aerobic exercise for 8 months. Intensity of exercise was adjusted individually for each horse according to a standardised exercise test. Stride kinematic characteristics at the trot were analysed by videog...
Crevier-Denoix N, Roosen C, Dardillat C, Pourcelot P, Jerbi H, Sanaa M, Denoix JM.Five sound mature horses, age 8-14 years, with toe angles 45.5-55.0 degrees were placed on a specially designed platform with only the left forelimb weightbearing, which allowed the successive production of 7 different conditions of foot orientation: neutral position (N), 5, 10, 15 degrees heel (H5, H10, H15) and toe (T5, T10, T15) elevation, performed according to 2 different sequences. For each condition, 2 lateromedial radiographs were taken to evaluate the metacarpophalangeal joint (MPJ) and both interphalangeal joint (PIPJ and DIPJ) angles, respectively. In addition, two-dimensional (2-D)...
Haussler KK, Bertram JE, Gellman K, Hermanson JW.Understanding the pathophysiology of equine back problems, for clinical evaluation, treatment or injury prevention, requires understanding of the normal 3-dimensional motion characteristics of the vertebral column. Recent studies have investigated regional vertebral kinematics; however, there are no reported measures of direct in vivo segmental vertebral kinematics in exercising horses. Relative movements between 2 adjacent vertebrae were recorded for 3 horses that were clinically sound and did not have a known history of a back problem. A transducer consisting of 2 fixtures and an array of li...
Faber M, Johnston C, Schamhardt HC, van Weeren PR, Roepstorff L, Barneveld A.Most research on equine kinematics has previously been performed in the walking and/or trotting animal. This is also true for the few studies on the kinematics of the equine back. These studies have, for the major part, focused on the flexion-extension movement in the sagittal plane. However, vertebrae can rotate in 3 dimensions. This study was designed to determine all 3 rotations in various segments of the vertebral column of a cantering horse. Five Dutch Warmblood horses were measured during treadmill canter (7.3 m/s). Steinmann pins were inserted into the dorsal spinous processes of 8 thor...
Robert C, Audigié F, Valette JP, Pourcelot P, Denoix JM.Speed related changes in trunk mechanics have not yet been investigated, although high-speed training is currently used in the horse. To evaluate the effects of speed on back kinematics and trunk muscles activity, 4 saddle horses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5 to 6 m/s. The 3-dimensional (3-D) trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was simultaneously obtained from the longissimus dorsi (LD) and rectus abdominis (RA) muscles using surface electrodes. T...
Burn JF, Brockington C.Deformation of the hoof capsule occurs during stance phase as a result of loading by the distal phalanx. The objective of this study was to evaluate optical motion capture as a technique for measuring hoof deformation during locomotion, and to quantify the deformation of the dorsal wall during stance phase. The front left feet of 3 clinically sound horses were used for this study. The hoof wall was cleaned and 9 retroreflective markers were glued to the lateral and dorsal hoof wall, and shoe. Each horse was trotted in a straight line at constant speed while marker positions during stance phase...
Khumsap S, Clayton HM, Lanovaz JL.The objectives of this study were to measure the effect of walking velocity on net joint moments and joint powers in the hindlimb during stance and to use the data to predict these variables at different walking velocities. Videographic and force data were collected synchronously from 5 sound horses walking over a force plate at a range of velocities. Force and kinematic data from 56 trials were combined using an inverse dynamic solution to determine net joint moments and joint powers. Analysis by simple regression and correlation (P or = 0.30, r > 0.50) showed that, in early stance, there...
Davies HM.The relationships were explored between measurements of bone quality, size (quantity) and shape, and strain data collected during treadmill exercise at 4 and 12 m/s from the third metacarpal bones of 6 yearling and 6 mature Thoroughbred racehorses. Peak strains in yearling and mature Thoroughbred horses during exercise were related to the size and shape of the third metacarpal bone. The peak strains were significantly lower in horses with a greater cross-sectional area of bone and with a greater proportion of the bone in the dorsal cortex. There was no consistent relationship between peak stra...
Baird DH, Pilsworth RC.Anecdotal evidence suggested that many cases of third tarsal bone (T3) fracture encountered clinically were associated with an abnormal shape to this bone. The radiographs of 10 normal horses and 10 horses affected with slab fracture of T3 were therefore examined to ascertain if any pre-existent radiological abnormality was present in cases of fracture. Measurement of the maximum and minimum width between the proximal and distal articular surfaces of the dorsolateral aspect of this bone was carried out on a standardised dorso-50 degrees medial-palmarolateral radiographic projection of the tars...
Alexander GR, Gibson KT, Day RE, Robertson ID.To measure the effects of transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) on flexor tendon and suspensory ligament (SL) strain in vitro. Methods: In vitro experimental biomechanical investigation. ANIMALS USED: Ten equine cadaver forelimbs. Methods: The effects of superior check desmotomy were determined using equine cadaver forelimbs secured in a servocontrolled hydraulic testing machine. Strain sensors were used to measure strain on the superficial and deep digital flexor tendons and SL, and a goniometer was used to measure join...
Tomlinson JE, Sage AM, Turner TA, Feeney DA.To map the equine pelvis using ultrasonography, validated by use of computed tomography (CT), magnetic resonance imaging (MRI), and measurements of frozen cadaver slices. Methods: 6 ponies and 6 horses. Methods: Ultrasonographic examination of the pelvis was performed on 6 clinically normal ponies. Measurements were obtained for imaged structures. Computed tomography, MRI, and measurements of frozen sections were performed after death and used to verify measurements. Linear regression determined the degree of correlation between measurements obtained ultrasonographically and the other modaliti...
Peham C, Licka TF, Scheidl M.To evaluate an adaptive-filter method for use in analysis of periodic electromyography (EMG) signals in which the transfer function of the filter is matched to characteristics of the signal. Methods: 15 adult horses without clinical signs of back pain. Methods: Electromyography signals of the left and right longissimus dorsi muscles, middle gluteal muscles, and triceps brachii muscle were recorded from horses walking on a treadmill, using bilaterally placed surface electrodes. A reflective marker was placed on the hoof of the left hind limb for simultaneous kinematic measurement of motion cycl...
Quiroz-Rothe E, Rivero JL.Combined methodologies of immunohistochemistry, histochemistry and photometric image analysis were applied: (1) to characterise control equine skeletal muscle fibres according to their myosin heavy chain (MyHC) composition and (2) to determine on a fibre-to-fibre basis the correlation between contractile [i.e. MyHC(s), myofibrillar ATPase (mATPase) and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) isoforms], metabolic [i.e. succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) activities, glycogen and phospholamban (PLB) contents], and morphological [i.e. cross-sect...
Gimsing S.Occupational injuries are notifiable in Denmark. Hitherto, occupational injuries caused by riding and horse handling have not been reported. Methods: This retrospective study comprises all cases reported to the National Working Environment Authority during the period 1992-1999. Results: There were 634 occupational accidents, and 43% of the victims were below the age of 25 years with a four-in-one female preponderance. In contrast, there were only three cases of occupational disease. Conclusions: Occupational diseases ought to be much more common than suggested by these few reported cases. Resp...
Garcia-Lopez JM, Boudrieau RJ, Provost PJ.A 4-year-old castrated male Miniature Horse was evaluated because of severe right hind limb lameness of 5 days' duration. The diagnosis of craniodorsal luxation of the right coxofemoral joint was made by physical examination and radiographic imaging. Closed reduction was attempted but was unsuccessful. Surgical reduction was successfully performed, using toggle pin, synthetic capsular reconstruction, and trochanteric transposition techniques. No postoperative complications were observed. Follow-up 26 months after surgery revealed no recurrence of the luxation and no evidence of lameness. These...
Eddy AL, Van Hoogmoed LM, Snyder JR.Equine thermography has increased in popularity recently because of improvements in thermal cameras and advances in image-processing software. The basic principle of thermography involves the transformation of surface heat from an object into a pictorial representation. The colour gradients generated reflect differences in the emitted heat. Variations from normal can be used to detect lameness or regions of inflammation in horses. Units can be so sensitive that flexor tendon injuries can be detected before the horse develops clinical lameness. Thermography has been used to evaluate several dif...
Geelen SN, Jansen WL, Sloet van Oldruitenborgh-Oosterbaan MM, Breukink HJ, Beynen AC.The aim of this study was to establish the dose-response relationship between fat intake and heparin-released plasma lipoprotein lipase (LPL) activity in horses. Eight mature trotters were fed 4 rations with different fat levels (3.0, 5.0, 7.7, or 10.8% fat in the dry matter) according to a 4 X 4 Latin square design. The experimental rations consisted of hay and different concentrates; the concentrates and hay were given in a 3:1 ratio on an energy basis. Soybean oil was added to the concentrates at the expense of isoenergetic amounts of glucose. Blood samples were taken at the end of each die...
Murray RC, Birch HL, Lakhani K, Goodship AE.It was hypothesized that cartilage macro-molecular characteristics are influenced by exercise intensity and by location within a joint. Objective: To determine the macromolecular characteristics of carpal articular cartilage at common and uncommon sites of pathology in horses undergoing high or low intensity exercise, and to compare this composition between exercise groups. Methods: Twelve horses (19.3+/-0.9 years) were assigned to exercise groups. Each group underwent 19 weeks high-intensity treadmill training (N=6) or low-intensity exercise (N=6). Dorsal and palmar test sites were identified...
Cherdchutham W, Becker CK, Spek ER, Voorhout WF, van Weeren PR.To determine the effects of exercise on collagen fibril diameter distribution in the superficial digital flexor tendon (SDFT) of foals. Methods: 43 Dutch Warmblood foals. Methods: From 1 week until 5 months of age, group-1 foals (n = 14) were housed in stalls and not exercised, group-2 foals (14) were housed in stalls but were exercised, and group-3 foals (15) were maintained at pasture. Biopsy specimens were collected from the SDFT at 2 months, and 8 foals in each group were euthanatized at 5 months. Remaining foals were housed together in a loose stall and paddock until euthanatized at 11 mo...
Meershoek LS, van den Bogert AJ, Schamhardt HC.To describe a method to calculate flexor tendon forces on the basis of inverse dynamic analysis and an in vitro model of the equine forelimb and to quantify parameters for the model. Methods: 38 forelimbs of 23 horses that each had an estimated body mass of > or = 500 kg. Methods: Longitudinal limb sections were used to determine the lines of action of the tendons. Additionally, limb and tendon loading experiments were performed to determine mechanical properties of the flexor tendons. Results: The study quantified the parameters for a pulley model to describe the lines of action. Furthermo...
Meershoek LS, Lanovaz JL.To test the sensitivity to measurement and modeling errors of a method for noninvasive calculation of flexor tendon forces in the equine forelimb and to calculate tendon forces for Dutch Warmblood horses during trotting. Methods: A normative set of kinematic and ground-reaction force (GRF) data obtained from horses during trotting in another study. Methods: Forces in the flexor tendons were calculated from the data set before and after addition of fixed relative and absolute errors. Amount of error was based on normal accuracy of the variables. A similar analysis was performed for a measure of...
Lacombe VA, Hinchcliff KW, Geor RJ, Baskin CR.The purpose of this study was to determine the effect of muscle glycogen depletion and subsequent replenishment on anaerobic capacity of horses. In a blinded crossover study, seven fit horses performed glycogen-depleting exercise on two occasions. Horses were infused after glycogen-depleting exercise with either 6 g/kg body wt of glucose as a 13.5% solution in 0.9% NaCl (Glu) or with 0.9% NaCl (Sal) of equivalent volume. Subsequently, horses performed a high-speed exercise test (120% of maximal rate of oxygen consumption) to estimate maximum accumulated oxygen deficit. Replenishment of muscle ...
Taylor D, Kuiper JH.This paper addresses an anomaly which exists in the current literature regarding stress fractures. Analysis of the data on fatigue strength of bone samples in vitro would conclude that these fractures should never occur at the strain levels known to occur in vivo. This anomaly can be resolved by including in the analysis the effect of stressed volume, whereby larger volumes of material are expected to have worse fatigue properties. A Weibull analysis was used to predict the probability of failure, Pf; this was an upper-bound prediction because it did not include the effects of remodelling and ...
Hood DM, Wagner IP, Taylor DD, Brumbaugh GW, Chaffin MK.To compare limb-load distribution between horses with and without acute or chronic laminitis. Methods: 10 horses with carbohydrate-induced acute laminitis, 20 horses with naturally occurring chronic laminitis, and 20 horses without foot abnormalities (controls). Methods: Limb-load distribution was determined, using a custom-designed system that allowed simultaneous quantification of the mean percentage of body weight voluntarily placed on each limb (ie, mean limb load) and the SD of the mean load over a 5-minute period (ie, load distribution profile [LDP]). Load distribution profile was used a...
Williams RB, Harkins LS, Hammond CJ, Wood JL.For improvements to the safety and welfare of racehorses to be possible, it is essential to have access to basic descriptive information about the veterinary incidents encountered during horseracing. A 3 year surveillance study (1996-1998) was conducted by The Jockey Club into racing injuries, other postrace clinical problems and fatalities from all 59 British racecourses (mainland Britain only) to identify risk factors. During the survey there were 222,993 racing starts: 106,897 starts in flat races on turf (47.9%), 26,519 starts in flat races on all-weather surfaces (11.9%), 30,932 starts in...
Robert C, Valette JP, Denoix JM.The purpose of this study was to evaluate the effects of speed and slope on the activity of trunk muscles. The electromyographic (EMG) activity of the splenius (Sp), longissimus dorsi (LD) and rectus abdominis (RA) muscles was recorded with surface electrodes during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and slope (0 to 6%). Raw EMG signals were processed to determine activity duration, onset and end and integrated EMG (IEMG). For the 3 muscles investigated, onset and end of activity were obtained earlier in the stride cycle when speed increased. A long...
Peham C, Licka T, Girtler D, Scheidl M.The aim of this study was to assess the influence of orthopaedic pain on the variation of stride length as a kinematic system-parameter in 21 horses with forelimb lameness. Data were collected while the horses were trotting on a treadmill during a minimum of 12 motion cycles, both before and after intra-articular or perineural anaesthesia. Stride length was assessed for each motion cycle, and the mean and standard deviation were calculated for each condition. Forelimb lameness was documented as percentage of asymmetry of vertical head movement. With significant decrease of forelimb lameness af...
Bukowiecki CF, Bramlage LR.Comminuted middle phalangeal fractures, extending into the proximal and distal portions of the interphalangeal joint, are associated with a poor prognosis for return to athletic performance. An 11-year-old horse with this type of fracture was treated successfully by use of a broad dynamic compression plate.
Shelver WL, Smith DJ.Zilpaterol is a β-adrenergic agonist feed additive approved in the United States to increase weight gain and improve feed efficiency of cattle. A zilpaterol immunochromatographic assay was developed as an economical and user-friendly rapid detection method for zilpaterol and validated using urine and tissue samples derived from animal studies. The assay sensitivity was 1.7-23.2 ng g or mL across a variety of feed and animal matrices and did not cross-react with clenbuterol or ractopamine. No sample pre-treatment of cattle and sheep urine was needed, but horse urine and feed required dilution;...
Blevins WE, Widmer WR.This article focuses on the principles involved in making radiographs of equine limbs; understanding radiographic anatomy, including normal variations; and principles of radiographic interpretation. The influence of pathogenesis of disease on the radiographic image is considered. Diseases associated with racing as well as the developing racehorse are discussed.
Reeves MJ, Trotter GW, Kainer RA.The anatomical and functional communications of the synovial sacs of the equine stifle joint were evaluated in 50 stifle joints of 25 horses. Femoropatellar joint (FPJ) sacs were injected with 50 ml of gelatin-based dye and horses were then walked for 50 m. Horses were subsequently killed, the stifle joints dissected and the location of the dye recorded. Twenty-three horses (46 joints) had clinically normal stifle joints and in this group, anatomical communications of the stifle joints were bilaterally symmetrical in each horse. In 15 of these 23 horses (65 per cent), direct anatomical communi...
Scott EA, Snyder SP, Schmotzer WB, Pool R.Probable cause of fracture in a Paint gelding was a congenital bone defect involving the extensor process area of the right and left forelimb distal phalanges. Radiographically and histologically, subchondral bone cysts at the fracture lines were suspected. These cysts were thought to have developed in association with abnormal ossification centers at the extensor process areas of the third phalanx. Partial avulsion of weak extensor processes would then occur from natural forces exerted on these weakened bony prominences via the common digital extensor tendon. Support for osteochondrosis as a ...
Shoemaker RS, Martin GS, Hillmann DJ, Haynes PF, McClure JR, Schneiter HL.Two horses became acutely lame following a fall during strenuous exercise and were diagnosed as having disruption of the caudal component of the reciprocal apparatus. Clinical signs consisted of lameness of the right pelvic limb, characterized by flexion of the hock and simultaneous extension of the stifle. Radiography revealed an avulsion fracture from the supracondylar tuberosity and fossa of the distal portion of the femur in one horse. Clinical and radiographic findings indicated avulsion of the lateral origin of the gastrocnemius and superficial digital flexor muscles. Treatment consisted...
Badoux DM.The ratio between the length of the anterior and posterior cruciate ligaments and the distance between their femoral and tibial attachments in the canine and equine knee joint reveals that these structures form a Tchebychev mechanism for parallel motion.
Cavani F, Fini M, de Terlizzi F, Cadossi M, Ciminelli L, Ortolani S, Cherubini R, De Aloysio D, Giavaresi G, Cadossi R, Canè V.Osteoporosis involves alterations, not only in density, but also in the architectural organisation of the bone; in particular, trabecular orientation, following the skeletal load directions, lends a high degree of stiffness to the whole bone. We investigated the relationship between trabecular orientation, density, stiffness and ultrasound (US) propagation in two orthogonal directions (par. = parallel to, and ort. = orthogonal to the main orientation of the trabeculae) in cylindrical equine bone specimens (thoracic vertebrae) where a preferential orientation is present. A total of 15 cylinders...
Mason TA.Seven cases of chronic tenosynovitis affecting the extensor carpi radialis or lateral digital extensor tendon and their sheaths are described. All cases were chronic and in 4 of the cases previous treatment by drainage and local corticosteroid injection had been ineffective. Surgical exploration of 6 cases demonstrated a distinct lesion and specific surgical treatment was carried out.
Adams SB.A fractured right supraglenoid tubercle in a 15-month-old Thoroughbred gelding was repaired by partial biceps brachii tenotomy, interfragmentary compression, and tension band wiring. The horse is currently being ridden daily and has remained sound for 4 years.
Kaneps AJ, O'Brien TR, Redden RF, Stover SM, Pool RR.The distal phalanx and metacarpal physis of both forelimbs of 32 Thoroughbred foals 3-32 weeks of age were radiographed to identify those limbs with osseous bodies at a palmar process (PP) of the distal phalanx. Osseous bodies (ossicles) were identified radiographically in 19% of the foals. Sixteen of the 32 foals were selected for microradiographic and histological evaluation: 6 foals with radiographic evidence of ossicles and 10 foals without. Fourteen ossicles of the PP were observed radiographically. Ossicles were either a triangular bone fragment at the palmar aspect of the distal angle o...
Sack WO, Ferraglio S.A study method has been devised to review clinically important structures of the equine hock joint on a fresh specimen. The review can be done alone; dissection takes about 2 hours; special tools or materials are not required.
Rivero JL, Serrano AL.Three different myosin heavy chain (MHC) isoforms have been identified in the equine gluteus medius muscle: the slow or MHC-I and the 2 fast MHC-IIA and MHC-IIX isoforms. They are distributed in 3 fibre types containing a single MHC (I, IIA, IIX) and 2 hybrid types co-expressing 2 isoforms (I + IIA, IIA + IIX). The aim of this study was to determine if heavy carriage training alters skeletal MHC composition in horses. Fourteen Andalusian mares age 42-46 months were used. Seven horses were used as controls to estimate the effects of growth on muscle. The remaining 7 horses underwent a training ...
Williams J, Miyabayashi T, Ruggles A, Yamamoto J, Takiguchi M.A 2.5-year-old female Thoroughbred horse was referred to the veterinary teaching hospital for right front limb lameness of 1 year duration. Physical examination and diagnostic nerve blocks failed to localize the origin of the lameness. Scintigraphy with 99mTc-MDP suggested increased radionuclide uptake in the palmar metacarpal soft tissues of the right front limb. Ultrasonographic examination revealed hypoechoic lesions in the superficial digital flexor tendon and the suspensory ligament, suggesting tendinitis and desmitis. Combined imaging modalities improved detection and characterization of...
Todhunter PG, Schumacher J, Finn-Bodner ST.Chronic lameness was determined to be caused by desmitis of the accessory ligament of the deep digital flexor tendon and adhesions associated with these 2 structures. Desmotomy of the accessory ligament, resection of adhesions, and controlled exercise during convalescence resulted in return to normal use without apparent lameness.