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.
Knight DA, Weisbrode SE, Schmall LM, Reed SM, Gabel AA, Bramlage LR, Tyznik WI.The potential role of dietary copper in the development of cartilage defects in foals was investigated. Twenty-one mares were fed rations containing 13 ppm copper (CuC, control) or 32 ppm copper (CuS, supplemented) during the last three to six months of gestation and first three months of lactation. Their foals were fed pelleted concentrate containing 15 or 55 ppm Cu and were destroyed at 90 (5 CuC and 5 CuS foals) or 180 (6 CuC and 5 CuS foals) days. Focal cartilage lesions were found at multiple sites on necropsy. In foals killed at 90 days, there were over twice (9 versus 4) as many lesions...
Orsini JA, Buonanno AM, Richardson DW, Nunamaker DN.A Salter-Harris type-II fracture of the distal portion of the femur in a 1-year-old Pony of America was repaired by use of lateral plating combined with interfragmentary compression. The configuration of the fracture and the method of internal fixation with a condylar buttress plate were unique and resulted in primary bone healing, seen at the 5-month follow-up examination.
Cymbaluk NF.Housing temperature effects on growth, feed utilization and feed digestion of 12, 7-mo-old Standardbred colts were evaluated for 22 wk beginning in late November. Colts were assigned to one of two treatments: housed in a barn heated at 10 degrees C (warm) or housed in a barn with no external heat supply (cold). All horses were allowed outdoors for 4 h daily. Mean temperatures of the warm and cold barn from November to April were 10.9 +/- .66 and -5.2 +/- 1.72 degrees C, respectively. Hair coat weight of cold-housed colts was 1.4- to twofold (P less than .05) that of warm-housed colts from Dece...
Little CB, Hilbert BJ, Wickstrom S, Hedlund BE.An alcian blue precipitation method for quantifying the hyaluronic acid (HA) and sulphated glycosaminoglycan concentration (SGAG) in solutions containing both compounds was assessed. The assay was found to be rapid and reliable in solutions containing 0 to 200 mg of HA/dl and 50 to 1,000 micrograms of SGAG/dl, and was not affected by the presence of protein, hemoglobin, or methemoglobin in concentrations normally found in synovial fluid. The HA and SGAG concentrations in intercarpal synovial fluid from 13 clinically normal and 11 arthritic horses were evaluated. A relationship was not found be...
Robinson JA, Naylor JM, Crichlow EC.The use of electromyography (EMG) as a diagnostic aid for equine hyperkalemic periodic paresis (EHPP) was investigated in seven affected and seven control horses. Affected horses were confirmed positive for EHPP either by elevated serum potassium concentration with clinical signs of myotonia, or by inducing hyperkalemia and clinical signs using oral potassium chloride challenge. All horses were asymptomatic at the time EMG was performed, using bipolar fine wire needle electrodes. The myopotentials were recorded on magnetic tape and displayed on paper charts for analysis. Insertional and restin...
Specht TE, Poulos PW, Metcalf MR, Robertson ID.Vacuum phenomenon was induced inadvertently during radiographic examination of a metatarsophalangeal joint of a lame horse. The phenomenon was recreated in a sound horse when a metacarpophalangeal joint was radiographed in a stress-flexed position. Distraction of apposing articular surfaces may induce the vacuum phenomenon, which could result in misdiagnosis of an osteochondral defect or fracture.
Kneller SK, Losonsky JM.Bilateral metacarpophalangeal radiographs of 100 Thoroughbreds were examined for visualization and location of the major nutrient foramen of the proximal phalanx. The foramina were located on the dorsal or palmar aspects of the cortex or were not visible radiographically. Of the 100 horses, 60 had the same pattern in both forefeet. In the remaining 40 horses, the left and right proximal phalangeal foramina were asymmetric. Of the 200 proximal phalangeal foramina (100 horses), 53 were on the dorsal aspect of the cortex and 101 were on the palmar aspect of the cortex; 46 were not visible radiogr...
Riley CB, Yovich JV, Huxtable CR.A fusion defect of the proximal and middle phalanges of both hindlimbs, osteochondrosis dissecans of the distal interphalangeal joints of the forelimbs, and subluxation of all 4 distal interphalangeal joints occurred in a Standardbred filly. Lameness was the first abnormality noted and was observed at one week of age in the left forelimb and progressed until all 4 limbs were affected by 5 weeks of age. On radiographs of both forelimbs, the distal interphalangeal joints were subluxated with irregularity and lucency of subchondral bone. On radiographs of the distal hindlimbs, there was a subluxa...
Lalatta Costerbosa G, Barazzoni AM, Clavenzani P, Callegari E.In this study the histochemical fiber type analysis of the articularis humeri muscle of the horse was performed. This muscle is composed of type I and type IIA fibers. A large number of spindles has been observed and the presence of these receptors could help to understand the role played by this muscle.
Specht TE, Miller GJ, Colahan PT.The breaking strength (stress at failure) of equine third metacarpal bones, with and without clustered drill holes, was determined in vitro. Paired ossa metacarpalia II-IV of 39 horses (n = 39) between 2 and 7 years old were tested in palmarodorsal 3-point bending. Four treatments were compared. Clustered 2.7- or 3.5-mm drill holes, in a 4- or 7-hole pattern, were made in the dorsal cortex of the distal diaphysis of the left third metacarpal bone. Undrilled right third metacarpi were used as controls. Bones with clustered drill holes failed by an oblique fracture through 1 or more drill holes,...
Langton CM, Ali AV, Riggs CM, Evans GP, Bonfield W.A portable system using a direct contact for the measurement of ultrasonic velocity and broadband attenuation in bone is described (contact ultrasonic bone analyser, CUBA). Soft-tissue compensation is performed using an ultrasonic pulse-echo technique. CUBA has been successfully validated using reference materials, the precision of velocity and broadband attenuation measurements being typically 0.2% and 0.5% respectively. The clinical reproducibility has been assessed on the equine third metacarpal bone. The reproducibility of velocity measurement is typically 0.5% for cortical bone and 1% for...
Kannegieter NJ.Chronic proliferative synovitis of 27 metacarpophalangeal joints in 16 horses is described. The diagnosis was based on a history of lameness and, or, poor performance, pain on flexion of the metacarpophalangeal joint, the response to intra-articular anaesthesia, and plain and contrast radiography. Radiographic findings included concavity of the distal dorsal metacarpus proximal to the sagittal ridge, and an increase in size of the synovial tissue adjacent to the proximal, dorsal attachment of the joint capsule. Mineralisation of the synovial tissue was present in some joints, and chip fracture...
Schougaard H, Falk Ronne J, Phillipson J.This research study investigated the prevalence and potential genetic factors of tibiotarsal osteochondrosis, a joint condition, in trotting horses in Denmark through a radiographic survey. The study examined 325 yearlings, […]
Nixon AJ.An arthroscopic procedure for examination of the digital flexor tendons and tendon sheath was developed in 16 equine limbs and 12 horses. Distension of the tendon sheath and insertion of the arthroscope was accomplished through a cul-de-sac on the palmar or plantar surface of the tendon sheath 1 to 2 cm palmar or plantar to the digital neurovascular structures and between the annular ligament and proximal digital annular ligament. A single arthroscope entry point allowed examination of all regions of the tendon sheath cavity and most surfaces of the digital flexor tendons within the sheath. Di...
Nunamaker DM, Butterweck DM, Provost MT.The North American Thoroughbred racehorse was chosen as a model to study the pathogenesis of fatigue failure of bone. This species has a high incidence of spontaneous fatigue failure of bone (bucked shins) during its early training. In vivo strain gauge studies of the third metacarpal bone of four young racehorses running at racing speeds showed high principal compressive strains [-4,841 +/- 572 (SD) microstrain] while two older horses had lower principal compressive strains (-3,317 microstrain measured at racing speed, -3,250 microstrain extrapolated from a slower speed run). Previously repor...
Hago BE, Plummer JM, Vaughan LC.The structure of equine synovial tendon sheaths and bursae has been examined by light and scanning electron microscopy. Tissue samples were obtained from horses of various types and ages with no clinical evidence of sheath or bursal disorders. The interior of both structures was lined by a cellular layer superimposed on a vascular zone supported by a fibrous layer. The pattern of cell distribution of the lining varied from site to site within the same structure depending on the nature of the underlying tissue and on the amount of movement to which the structure was subjected. The cellular laye...
Nishita T, Matsushita H.A sensitive sandwich enzyme immunoassay (EIA) for measuring equine carbonic anhydrase III (CA-III) was established using a microplate as a solid-phase and peroxidase as a labelling enzyme. The assay can detect concentrations as low as 5 ng/ml using 20 microliters of sample sera. Within-run coefficients of variation obtained using standard equine CA-III were less than 5 per cent. CA-III levels in equine serum ranged from 5 to 50 ng/ml (n = 370), and apparently abnormal levels of CA-III from 100 to 1900 ng/ml (n = 27) were observed. The concentrations of immunoreactive CA-III in the extracts of ...
Carlin JI, Harris RC, Cederblad G, Constantin-Teodosiu D, Snow DH, Hultman E.Treadmill exercise of 2-min duration and increasing intensity resulted in increased formation of acetyl-CoA and acetylcarnitine in working muscle of Thoroughbred horses. At high work intensities a plateau was reached for both acetyl-CoA (approximately 50 mumols/kg dry muscle) and acetylcarnitine (approximately 20 mmol/kg dry muscle). Postexercise concentrations were significantly (P less than 0.001) correlated; [acetylcarnitine] = 349.[acetyl-CoA] + 2.4. The results indicate that approximately 350 mumols acetylcarnitine were accumulated for every 1 mumol acetyl-CoA. Under the conditions of exe...
Barrey E.A greater knowledge of the biomechanics is necessary in equine orthopaedics, therapeutics, farriery and for the selection of athletic horses. The purpose of this study was to determine the normal distribution of the vertical component of the hoof force using a measuring boot. The measurements were carried out using 20 sound horses walking and trotting on a straight hard track. A force measuring horseshoe, attached to the foot with a boot, provided continuous recording of vertical forces at four locations on the hoof. For each measuring location, a computer program produced curves and calculate...
van Weeren PR, van den Bogert AJ, Barneveld A, Hartman W, Kersjes AW.The function of the reciprocal apparatus in the hind limb of the horse was studied by kinematic gait analysis. For recording purposes a modified opto-electronic CODA-3 kinematic analysis system was used. The raw kinematic data were corrected for skin displacement artifacts by use of recently developed correction models. It was concluded that contradictory findings about the coupling of tarsal and stifle joints by the reciprocal apparatus, when comparing in vitro and in vivo studies, can be fully attributed to artifacts due to the movement of the skin markers over the underlying bony structures...
Clayton HM.High speed cinematography was used to measure the timing and distance characteristics of the trot in five sound horses. Two farriery treatments were compared: (1) normal, in which the dorsal hoof wall was aligned with the pastern axis in all four feet and (2) acute hind hoof angulation, in which the hind toes were allowed to grow relatively longer than the heels, so that the angulation was approximately 10 degrees lower than the normal hind hoof angle for the individual animal. Comparison between the two treatments showed that the acute hind hoof angulation was associated with significant incr...
van Weeren PR, van den Bogert AJ, Barneveld A.Displacement of skin over the underlying skeletal structures in the proximal parts of the limbs was investigated in four walking Dutch Warmblood horses. Movement of the skin was visualised with self adhesive spot labels whereas that of the skeletal parts was visualised indirectly by means of a plastic strip connected to a transcutaneous Steinmann pin, driven into the bone of interest. Consistent results for all four horses were found. Individual and mean total displacements ranged from 1 to 4 cm (distal scapula) to 13 to 17 cm (caudal part of the greater trochanter of the femur). Displacements...
van Weeren PR, van den Bogert AJ, Barneveld A.Skin displacement was investigated at 16 sites in the front and hind limbs of four Dutch Warmblood horses at the trot. For visualisation of the bone under the skin, a measuring device mounted on a Steinmann pin driven into the bone under investigation, was employed. Mean displacements ranged from 8 mm (X-displacements proximal and distal metacarpus) to 142 mm (Y-displacement caudal part of greater trochanter). When compared with previously determined skin displacement patterns at walk, mean displacements at trot were of the same magnitude whereas the shape of the time-displacement curve was di...
Kraus BM, Ross MW, Boswell RP.Two 2-year-old pacers, a 3-year-old pacer and a 2-year-old-trotter with acute forelimb lameness were admitted for nuclear scintigraphic examination. Horses were grade 3-4/5 lame. There was increased radiopharmaceutical uptake (IRU) in the distal cranial medial aspect of the humerus in one horse and along the caudal humeral cortex in the other three horses. Two of the four horses were affected bilaterally. Radiographic abnormalities consisted of thickening of the caudal cortex of the mid-diaphysis of the humerus but radiographic changes were not present in all horses. All horses were managed wi...
Martins EA, Silva LC, Baccarin RY.The objective of this study was to evaluate, through ultrasonography, the effect of medial patellar desmotomy. Middle patellar desmitis, enthesophytes in the patella, and irregularities in the cartilage of the femoral trochlear groove were observed. Medial patellar desmotomy leads to lesions in the stifle, and restriction of movement does not prevent these lesions from occurring. L’objectif de cette étude était d’évaluer, par échographie, l’effet d’une desmotomie du ligament médial de la rotule. Une desmite du ligament médial de la rotule, des enthésophytes dans la rotule et de...
Stewart RH, Bertone JJ, Yvorchuk-St Jean K, Reed SM, Neil WH.Hyperkalemic periodic paralysis (HPP), characterized by intermittent episodes of muscle fasciculations, profound muscle weakness, and hyperkalemia, has been described in Quarter Horses, Appaloosas, and Paints. In previous reports, the hallmark of this syndrome has been the development of hyperkalemia during each episode. Two affected horses had episodes of paralysis without associated hyperkalemia, demonstrating that normokalemia during an episode otherwise consistent with HPP does not eliminate HPP as a diagnosis. This clinical presentation appeared to be a variant of HPP.
de Souza AF, Paretsis NF, De Zoppa ALDV.The aim of this study was to determine the clinical outcomes reported in retrospective studies of proximal interphalangeal arthrodesis (PIA) in horses through a meta-analysis of retrospective studies. CAB Abstracts, PubMed, ScienceDirect, Web of Science, and Scopus were searched. The primary outcomes included survival and surgical site infection (SSI) rates, return to activities, and time of hospital stay and casting. Subgroups were formed for fractures and other conditions. Meta-analyses were performed with fixed and random effects models to estimate proportions, mean values, and effect size ...
Wyn-Jones G, Peremans KY, May SA.The management of a case of quadrilateral flexural contracture in a 10-year-old pony is described. The animal was restored to normal appearance and function through a combination of surgical desmotomy and management techniques; the importance of analgesia and exercise as adjuncts to surgery is emphasised. The aetiology and pathogenesis of the condition in the immature animal and the adult is compared and a possible association is made between this condition and palmar fibromatosis (Dupuytren's contracture) occurring in man.
Bohn A, Papageorges M, Grant BD.Ultrasonography and radiography were used to diagnose bicipital tenosynovitis and humeral osteitis in a horse with a history of lameness of 7 weeks' duration. Surgical exploration confirmed the diagnosis.
Ayala I, Rodríguez MJ, Aguirre C, Buendía AJ, Belda E, Laredo FG.This report describes a case of postanesthetic brachial triceps myonecrosis affecting only the left forelimb of a horse. A fatal unilateral postanesthetic myonecrosis has not been previously reported in the horse. This article describes the factors in the horse's history, the anesthetic protocol, and the treatment that may have led to this condition. Ce rapport décrit un cas de myonécrose postanesthésique du triceps brachial affectant seulement la patte avant gauche. Une myonécrose postanesthésique unilatérale mortelle n’avait pas encore été signalée chez le cheval. Le présent art...
O'Connor CI, Nielsen BD, Schott HC, Clayton HM.Weight training is commonly used by human athletes to increase strength and fitness. This study was performed to examine the effect of weight-carrying and nutritional supplementation on muscle development and growth in young horses. This study examined the effect of weight-carrying and nutritional supplementation on muscle development and growth. Seventeen horses were divided into 3 groups: controls exercised in a free-flow exerciser, a weight group that performed the same exercise, carrying progressively increasing weight up to 45 kg, and a weight-supplement group, that also received a myo-an...