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.
Sack WO.The nerve distribution to the digit of the horse was studied with the compound microscope in serial transverse sections of fetal limbs and plotted on life-size outlines of the horse's foot. It was learned that there is much variation in the topography of the branches of the principal nerves. There is no mirror-image nerve distribution on the 2 sides of the foot. The dorsal branch of the ulnar nerve does not extend below the fetlock. The communication between the palmar metacarpal nerves and branches of the dorsal branch of the digital nerves is only a crossing of nerves without exchange of fib...
Takeuchi K, Shibata N, Senda N.Myosin was isolated from leucocytes in horse arterial blood by the same procedures used for the isolation of myosin from skeletal muscle. The Ca2+-, EDTA-, and Mg2+-ATPase [EC 3.6.1.3] activities of the protein was 0.148, 0.147, and 0.001 mumoles/min/mg, respectively, in 0.5 M KCl at pH 7.0 and 25 degrees. The Ca2+-ATPase activity decreased with decrease in the ionic strength. No difference was found between leucocyte myosin and skeletal myosin in the pH profiles of Ca2+- and EDTA-ATPases. The rate and amount of the initial burst of Pi liberation of leucocyte myosin were 0.002 mumoles/min/mg a...
Jeffcott LB, Hickman J.This paper describes the surgical treatment of 14 horses exhibiting chronic back pain attributed to impaction and overriding of the dorsal spines in the thoracolumbar region. The technique involved the resection of the summits of one or more dorsal spines following midline division of the supraspinous ligament. All the horses returned to full work after a convalescent period of at least four months, and 12 of them showed considerable improvement in their form and performance. A post-surgical complication encountered in one case was the development of new bone on the edge of a resected spine. T...
Menschik A.Mobility of the knee of the horse. The modification of medial and lateral femoral condyles by additional movement of the cruciate ligaments shown on the animal joint. Final rotation in the human knee-joint shapes the femoral condyles by additional movement of the cruciate ligaments. The roll-slide movement and final rotation lead to curving of the medial condyle of the femur in the transverse plane. The transition from the roll-slide into a tilting movement in the final phase of ultimate rotation reduces the power of the posterior ligamentous system of the knee-joint when there is a force tend...
Hördegen KM.115 horseback riders have undergone clinical and radiologic examinations of the spine. A minimum of 10 years' riding was required. Depending on intensity of training and number of riding hours, the subjects were divided into three groups: roughriders, sport riders and hobby riders. It was striking that of the bare half of cases (51) suffering from lower back, only 8 (about 15%) had had medical treatment and actually been disabled. Moreover, 47% of the riders with lower back pain were painfree in the saddle, i.e. when riding. No causal connection was found between riding and a higher incidence ...
Brown MP, MacCallum FJ.Tetracycline-labeled bones of 23 foals from 52 to 104 days old were sectioned and macroscopically examined to assess the extent of ossification or fusion of ossification centers. A grading system was devised with which to record information about the ossification centers and growth plates. The objective was to define anatomic standards which could contribute toward obtaining an accurate radiologic interpretation. Labeled limb bones of 3 neonatal foals were similarly treated, but grading of these was limited to the consideration of whether each site was still cartilaginous or had commenced to o...
Crowhurst RC.Diseases of the back of horse and man are not comparable owing to the great difference in anatomy and posture. Veterinary surgeons, particularly in the United Kingdom, are often requested to account for a poor performance due to suspected "back trouble" but a complete examination of the horse's back is most difficult and care must be taken first to exclude any limb or foot lesions. Diseases of the bones, nerves and muscles are briefly discussed. Diagnosis must be improved by new radiographic and biochemical tests before the significance of back lesions can be assessed or even treated.
Beckett SD, Walker DF, Hudson RS, Reynolds TM, Purohit RC.A needle-tipped catheter or subminiature pressure transducer was implanted in the corpus spongiosum penis (CSP) of Shetland Pony stallions to determine pressure during coitus. Electrodes for monitoring the electromyographic (EMG) activity were implanted in the ischiocavernosus (IC) and bulbospongiosus (BS) muscles. The mean peak CSP pressure recorded with the catheter was 762 mm of Hg, and with the subminiature pressure transducer, it was 994 mm of Hg. The simultaneous occurrence of the CSP pressure peaks and bursts of BS muscle activity indicated that these muscles were the likely source of e...
Jeffcott LB.A description of some of the clinical features of low back pain in the horse has been given and a number of methods for assisting diagnosis considered. As well as a complete clinical examination both at rest and during exercise, a useful diagnostic aid in some chronic cases was the injection of local anaesthetic into the interspinous spaces. A laboratory examination, including haematological and biochemical profiles, was undertaken in all cases. The serum enzymes GOT and CPK were particularly valuable as an aid to diagnosis in atypical tying-up. A technique for radiography of the vertebral col...
Jackson RK.The structural differences in the spine of the horse and man are compared. These, together with the different uses to which the spine is put, explain the different patterns of disease. Impingement of the spinous processes is discussed in detail including surgical treatment. Comments are also made on sacroiliac strain and manipulation of the spine.
Dordel HJ.Since November 1973 a riding course has been carried out with six blind adults. Due to the instructional methods the participants were able to ride independently, without an attendant, after only 30 hours. The effects of riding on the blind encompass coordination training and development of muscle strength. Furthermore, riding has a pronounced influence on the circulatory system. This attractive reaction activity provides the person who, as a result of his specific handicapping condition is limited in both the spatial and social fields, with an expansion of his living space and sphere of exper...
Courtot D, Mouthon G, Roux L, Jeanin E.The practise of repeated doping of the sport horse led us to examine its effects on the health of the animal, and particularly on muscular activity. The main doping agent used at present (acepromazine) has already been studied (COURTOT et al., 1974). In this paper, we study the secondary effects of diazepam, a derivative of the benzodiazepine series, which is being used more and more frequently on horses. In treated animals as compared to controls, we observe: -- a slight respiratory depression related solely to effort, -- an increase in seric creatine phosphokinase rate with no apparent relat...
Minetti AE, Cisotti C, Mian OS.Although the 3D trajectory of the body centre of mass during ambulation constitutes the 'locomotor signature' at different gaits and speeds for humans and other legged species, no quantitative method for its description has been proposed in the literature so far. By combining the mathematical discoveries of Jean Baptiste Joseph Fourier (1768-1830, analysis of periodic events) and of Jules Antoine Lissajous (1822-1880, parametric equation for closed loops) we designed a method simultaneously capturing the spatial and dynamical features of that 3D trajectory. The motion analysis of walking and r...
Camargo Garbin L, McIlwraith CW, Frisbie DD.Platelet-rich plasma (PRP) as well as other platelet-derived products have been used as a potential disease-modifying treatment for musculoskeletal diseases, such as osteoarthritis (OA). The restorative properties of such products rely mainly on the high concentrations of growth factors, demonstrating encouraging results experimentally and clinically. Yet, the autologous blood-derived nature of the PRP product lead to limitations that precludes it's widespread use. The main limitations for PRP use are; product variability, the need for minimum laboratory settings in most cases, and the need fo...
Vanderperren K, Gielen I, Van Caelenberg A, Van der Vekens E, Raes EV, Hauspie S, van Bree H, Saunders JH.This article describes the ultrasonographic (US) appearance of bony abnormalities on the dorsal aspect of the third metacarpal/metatarsal bone of the equine fetlock in cadavers with radiographic signs of osteoarthrosis. After US, computed tomography was undertaken to better characterise the lesions. Twelve fetlock joints were collected and all had more than one bone abnormality on US. Normal subchondral bone appeared on US as a well-defined and regular hyperechoic line with distal acoustic shadowing. Bone abnormalities detected on US included (1) gaps in the proximal subchondral bone filled wi...
Laverty S, Stover SM, Bélanger D, O'Brien TR, Pool RR, Pascoe JR, Taylor K, Harrington T.Clinical radiographic (LM and D35L-P1MO views), high detail radiographic, microangiographic and histological findings of the distal portion of the tarsus of 16 horses (five weanling, four young and six adult), without known clinical histories, were evaluated to determine the sensitivity of clinical radiographs for the detection of abnormalities in the distal tarsus and the prevalence of abnormalities in this population. Clinical radiographic and high detail radiographic abnormalities were observed in at least 30 per cent of the tarsi examined. Statistical agreement between observations from cl...
Suwannachot P, Verkleij CB, Van Weeren PR, Everts ME.We studied the effects of exercise without or with a subsequent period on pasture on Ca2+ ATPase concentration in foal skeletal muscle, and compared the results with those previously reported on Na+, K+ ATPase. Ca2+ ATPase was measured in homogenates as Ca2+-dependent steady-state phosphorylation from [gamma-32P]ATP. From day 7 after birth, 24 foals were divided into three groups: (i) staying in a box stall (Box); (ii) staying in a box stall with an exercise programme of an increasing number of sprints per day (Exercise); and (iii) staying on pasture (Pasture). Half of the foals (12 with four ...
Speirs VC, Bourke JM, Anderson GA.Four variations of abductor muscle prosthesis for treating laryngeal hemiplegia were evaluated in 153 horses by questionnaire, and in the 100 Thoroughbred racehorses in this group survival analysis was used to compare their racing performances and earnings with those of 400 control horses. The questionnaire indicated that the technique which included a ventriculectomy and 2 prostheses was regarded as being the most successful (P less than 0.01) and resulted in the least residual stertor (P less than 0.001). Survival analysis showed that there was no significant difference between the treated g...
Caudron I, Grulke S, Farnir F, Aupaix R, Serteyn D.This study is part of a work to develop a radiographic method that defines objectively the individual conformation of an equine digit and its appropriate trimming. The authors used isolated distal limbs fastened on a rotation support with variable inclinations to study the influence of induced asymmetric bearings on various angles measured from specific radiographs. The digit responded to asymmetric bearings by 1. deformation of the hoof; 2. rotation of the phalanges; and 3. joint asymmetry or local articular space narrowing. The two last situations occurred mainly in the distal interphalangea...
Contino EK.Joint disease is one of the most common issues effecting sport horses. Because there is no cure for joint disease, treatment goals surround slowing progression of the disease, minimizing pain, increasing function, and optimizing performance. Accomplishing these goals often requires a multimodal approach that combines systemic medications or supplements; intra-articular therapies, such as corticosteroids or biologics; management considerations; and physical therapy exercises.
Valberg SJ, Iglewski H, Henry ML, Schultz AE, McKenzie EC.Selective breeding and discipline specific training has led to equine breeds adept at various athletic disciplines. Breed-specific skeletal muscle adaptations have been studied in many breeds but not Warmbloods (WB). We evaluated gluteal muscle contractile muscle fiber types and citrate synthase activity (CS), a marker for mitochondrial volume density, in WB trained for dressage (second level-Grand Prix) contrasted with Quarter Horses (QH). Gluteus medius muscle biopsies from 14 unfit/18 fit dressage-trained WB and 20 unfit/16 fit reining/working cow QH were analyzed fluorometrically and fiber...
Anderson K, Morrice-West AV, Walmsley EA, Fisher AD, Whitton RC, Hitchens PL.Musculoskeletal injuries are observed in Thoroughbred racehorses and may become catastrophic. Currently, there are limited methods for early detection of such injuries. Most injuries develop gradually due to accumulated damage, providing the opportunity for early detection. Horses experiencing pain or lameness may exhibit changes in behaviour so the development of an objective, real-time system monitoring horse behaviour may enable detection of bone injuries before catastrophic failure. Objective: To determine whether intensive observational methods of assessing horse behaviour can be replaced...
Valberg S, Häggendal J, Lindholm A.Six horses with a history of recurrent exertional rhabdomyolysis (RER) and 7 control horses performed both a 55-min submaximal and later a 10-min near-maximal exercise test on a treadmill. Blood samples were obtained during exercise and gluteus medius muscle biopsies were obtained before and immediately after each exercise test and at 24 h after completion of the submaximal test. Rhabdomyolysis was developed by 3 of 6 RER horses during submaximal exercise and in 1 of the RER horses during near-maximal exercise. Concentrations of potassium, glucose, free fatty acids, ammonia, lactate, cortisol,...
Hawkes CS, Hahn CN, Dixon PM.Dysfunction of the muscles is implicated in the pathogenesis of intermittent dorsal displacement of the soft palate (DDSP) in exercising horses. The histological features of normal equine soft palate muscles have not been previously described. Objective: To describe the histological and morphometric features of normal equine soft palate muscles. Methods: The palatinus, palatopharyngeus, levator veli palatini and tensor veli palatini muscles of 6 Thoroughbred type horses were examined histologically and histochemically to assess their general morphology, fibre-type distribution and mean fibre d...
van Schie HT.The ultrasonic examination of tendons and ligaments of the distal limb of the horse improves the diagnostic possibilities of these frequently injured structures. The successful application is based upon a reliable knowledge of the normal sonographic anatomy and upon a standardized, flawless technic of the examination. Practice and experience allow the recognition of minor alterations which enables a more precise diagnosis, a more reliable prognosis, and in follow-up examinations also more specific information about the further use of the horse.
Brossi PM, Moreira JJ, Machado TS, Baccarin RY.This systematic review aimed to present and critically appraise the available information on the efficacy of platelet rich plasma (PRP) in equine and human orthopedic therapeutics and to verify the influence of study design and methodology on the assumption of PRP's efficacy. We searched Medline, PubMed, Embase, Bireme and Google Scholar without restrictions until July 2013. Randomized trials, human cohort clinical studies or case series with a control group on the use of PRP in tendons, ligaments or articular lesions were included. Equine clinical studies on the same topics were included inde...
Nevens AL, Stover SM, Hawkins DA.To quantify the passive contribution of the biceps brachii muscle-tendon unit to the limits of elbow joint extension during shoulder joint flexion in horses. Methods: Normal right forelimb specimens from 6 Thoroughbred cadavers. Methods: Specimens included the scapula, humerus, radius-ulna, biceps brachii muscle-tendon unit, and stabilizers of the shoulder and elbow joints. Specimens were mounted to a rigid board by transfixation pins through the humerus and instrumented for mechanical manipulation of the limb and joint angle and load measurements. Flexion and extension limits of shoulder and ...
Biau S, Burgaud I.Kinesiology taping (KT) has been used on human subjects for many years. More recently, KT has been used in sport horses. The physiological mechanisms involved remain unclear and its benefits are controversial. Objective: To investigate the effects of application of kinesiology taping to abdominal muscles on locomotor parameters before and after lungeing exercise in horses. Methods: Cross-over study. Methods: Eleven horses were tested twice, once with an application of KT without tension on abdominal muscles (condition 1) and once with a facilitation application of KT on abdominal muscles (cond...
Riemersma DJ, van den Bogert AJ.A procedure is described by which the length of a tendon at the onset of loading is determined objectively. The procedure includes the fitting of third-order polynomial functions on the load-elongation data. The onset of loading is detected by an increasing fit of the polynomial by selective data reduction of the initial part of the load-elongation curve. The procedure results in an objective and reproducible definition of the zero strain level of a tendon.
Da Costa Gómez TM, Radtke CL, Kalscheur VL, Swain CA, Scollay MC, Edwards RB, Santschi EM, Markel MD, Muir P.To determine whether bone microcracks are altered after application of focused and radial extracorporeal shock wave therapy (ESWT) to the equine distal limb. Methods: An ex vivo experimental model. Methods: A contralateral limb specimen was obtained from 11 Thoroughbred racehorses with a unilateral catastrophic injury. Distal limb specimens were also obtained from 5 non-racing horses. Methods: Three separate skin-covered bone segments were obtained from the mid-diaphysis of the metacarpus (MC3) or metatarsus (MT3). Focused (9,000 shockwaves, 0.15 mJ/mm2, 4 Hz) and radial (9,000 shockwaves, 0.1...
Yuda Y, Kasashima Y, Kuwano A, Sato K, Hattori S, Arai K.Upregulation of hyaluronidase 2 (HYAL2), one of somatic hyaluronidase (HAase), was demonstrated in granulation tissue during the healing of equine superficial digital flexor tendon injuries. The activity of HAase was assessed by hyaluronan (HA)-containing gel zymography and in situ zymography using frozen sections obtained from normal and injured tendon tissues. Elevated HAase activity was identified in the extract from the tendinopathic tissues, with lower levels of the activity in normal tendons. In situ zymography using fluorescently-labeled HA demonstrated HAase activity in the granulation...
Fuglbjerg V, Nielsen JV, Thomsen PD, Berg LC.Arthrosis of the articular process joints (APJs) in the caudal thoracolumbar region of horses may cause back pain and subsequent reduced performance or lameness. Ultrasound-guided injections of the APJs of the equine back have been described only briefly in the literature. Objective: To evaluate factors affecting the accuracy of intra-articular injections of the APJs in the caudal thoracolumbar region. Methods: One-hundred-and-fifty-four injections with blue dye were performed on APJs including the T14-L6 region in 12 horses subjected to euthanasia for reasons unrelated to back problems. The b...
Tokuriki M, Ohtsuki R, Kai M, Hiraga A, Oki H, Miyahara Y, Aoki O.We recorded the electromyographic (EMG) activity of 7 skeletal muscles in the forequarters and 1 in the hindquarters of 6 Thoroughbred horses during overground walking, swimming in a circular pool, and walking and trotting in a water treadmill. Bipolar fine wire electrodes were inserted into the muscles and the EMG signals were recorded using a telemetric system. The splenius exhibited tonic EMG activity during swimming. The brachiocephalicus showed its highest intensity during swimming followed by the walk and trot in the water treadmill and then walking overground. The triceps brachii caput ...
Textor J.Autologous biologic therapies such as platelet-rich plasma and autologous conditioned serum are in widespread clinical use to treat musculoskeletal pathology in horses. These substances exert a therapeutic effect through the provision of either anabolic or anti-catabolic factors, or a combination of both. This article discusses the history, experimental and clinical literature, and currently accepted preparation and usage strategies for both platelet-rich plasma and autologous conditioned serum.
Hopper N, Singer E, Henson F.The exact aetiology and pathogenesis of microdamage-induced long bone fractures remain unknown. These fractures are likely to be the result of inadequate bone remodelling in response to damage. This study aims to identify an association of osteocyte apoptosis, the presence of osteocytic osteolysis, and any alterations in sclerostin expression with a fracture of the third metacarpal (Mc-III) bone of Thoroughbred racehorses. Methods: A total of 30 Mc-III bones were obtained; ten bones were fractured during racing, ten were from the contralateral limb, and ten were from control horses. Each Mc-II...
McGowan CM, Fordham T, Christley RM.Telephone surveys of 34 racing yards with 1276 horses in training were made to establish the overall incidence of exertional rhabdomyolysis in the previous year. A case-control study was used to investigate the risk factors for the syndrome in 12 yards selected on the basis of the routine confirmation of diagnoses by the evaluation of the serum activities of creatine kinase and aspartate aminotransferase. The overall incidence of the syndrome was 6.7 per cent and 80 per cent of the trainers had at least one affected horse. In 74 per cent of the affected horses it frequently recurred, with an a...
Davies HM.In Thoroughbred racehorses, the dorsal cortex (DC) of the third metacarpal bone (MC3) enlarges when horses are first exposed to fast exercise speeds. It is now possible to measure ultrasound speed through 3 to 5 mm depths of bone around the bone shaft using Sunlight Medical's 'Omnisense' machine. The aim of this experiment was to determine whether the ultrasound speed measured in the surface 3-5 mm of the midshaft dorsal cortex of MC3 could be related directly to the midshaft shape and size of the MC3s of young Thoroughbred racehorses at the same stage of training. Sixteen 2-year-old and sixte...
Zambruno T, Georgopoulos SP, Boden LA, Parkin TDH.To examine the association between prerace administration of phenylbutazone and the risk of musculoskeletal injury (MSI) and fatal injury in Thoroughbred racehorses that raced between 2006 and 2015 at 2 of the 4 official racetracks in Argentina. Methods: Data from racetrack databases and veterinary reports on 283,193 race starts. Methods: Data were collected relating to race performance and injury outcomes for starts at these tracks. The incidence of MSI and fatal injury was calculated for each year, stratified by the declared prerace administration of phenylbutazone. Univariable logistic regr...
O'Neill HD, Ballegeer EA, De Feijter-Rupp HL, Stick JA, Derksen FJ, Robinson NE.Current diagnosis of recurrent laryngeal neuropathy (RLN) depends upon disease recognition in the clinically affected horse. Biopsy of the intrinsic laryngeal muscles may provide a method to identify the changes in fibre-type composition that occur in RLN before clinical signs become apparent. Objective: To develop an ultrasound-guided biopsy technique of the left cricoarytenoideus lateralis muscle (CALM) and evaluate its efficacy and safety in vivo. Methods: A longitudinal descriptive study. Methods: Six standing horses underwent ultrasound-guided biopsy of the left CALM. Frozen muscle cores ...
van Zadelhoff C, Ehrle A, Merle R, Jahn W, Lischer C.Impinging processi spinosi in the equine thoracic spine are a common cause of poor performance in the horse. A modified semiquantitative scintigraphic image analysis has been proposed for the evaluation of equine processi spinosi. This technique showed a high inter- and intraobserver agreement when compared to subjective and semiquantitative image analysis. The aim of this retrospective, method comparison study was to evaluate the agreement of the modified semiquantitative scintigraphic image assessment with previous methods of interpretation and to compare these scintigraphic evaluation techn...
Orsini JA, Ryan WG, Carithers DS, Boston RC.To generate data on the effects of firocoxib administration to horses with osteoarthritis. Methods: Client-owned horses with signs of lameness and joint pain associated with osteoarthritis. Methods: Firocoxib was administered as an oral paste (0.1 mg/kg, q 24 h) for 14 days. Assessments were performed on day 0 (baseline) and days 7 and 14. Results: 390 of 429 horses from 80 sites in 25 states met the criteria for analysis. Quarter Horse and Thoroughbred were the 2 most commonly represented breeds, comprising half of the study population. Signs of musculoskeletal pain or lameness attributed to ...
Engelbert TA, Tate LP, Richardson DC, Honore EK, Little ED.Bilateral luxation of the patella in four Miniature Horses was corrected by a lateral release incision and medial imbrication of the parapatellar fascia to the tendon of the sartorius muscle. Before surgery, the four horses had a grade 3 to 4 lateral patellar luxation bilaterally and had difficulty walking. Trochlear ridge hypoplasia was evident on radiographs in each horse. Follow-up information varied from 11 months to 4 years after surgery. Three horses had no patellar luxation or lameness. The other horse had a normal right stifle, but patellar luxation (grade 3) had recurred on the left.
