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.
Gunn HM.A modification of the histochemical reaction to demonstrate myosin adenosine triphosphatase activity in skeletal (striated) muscle was used to define the density of capillaries in transverse sections of 3 muscles (semitendinosus, diaphragm, and pectoralis transversus) of horses and dogs. Thoroughbred horses and Greyhound dogs, breeds noted for their speed in running, were compared with other members of their respective species. Thoroughbred cross horses were grouped with non-Thoroughbreds for comparison with Thoroughbreds. The area of muscle supplied by a capillary was remarkably similar in mu...
Nyack B, Morgan JP, Pool R, Meagher D.Osteochondrosis of the shoulder joint in the horse was diagnosed radiographically in 54 shoulders of 38 horses. Clinical signs were those of an intermittent lameness characterized as a swinging leg shoulder lameness with pain elicited by extension, flexion or abduction of the limb. Diagnosis of shoulder lameness was supported by blocking the shoulder joint with local anesthetics. Radiographic changes consisted of: (1) alteration in the contour of the humeral head and glenoid cavity, (2) periarticular osteophyte formation, (3) sclerosis of the subchondral bone, and (4) bone cyst formation. The ...
Irwin DH, Howell DW.An easy diagnostic technique for recognising fibrotic myopathy and scarring in the caudal popliteal area is described. A simplified corrective surgical technique is offered and discussed briefly. Some aspects of haematomas are reviewed.
Gingerich DA, Auer JA, Fackelman GE.A single intra-articular injection of 20 or 40 mg of purified hyaluronic acid of rooster comb origin resulted in restoration of normal joint function in horses with experimentally induced osteoarthritis. The functional improvement, measured by pressure sensitive force plate techniques, was detectable within one week after treatment and persisted throughout a four week experimental period despite continued use of the joints. The response was dose dependent in that injection of 0 (saline), 5 or 10 mg hyaluronic acid per joint space resulted in no significant change in joint function while dosage...
Goyal HO, MacCallum FJ, Brown MP, Delack JB.Measurements were made of growth at the extremities of all the long bones of the left limbs of 23 horses between 52 and 104 days of age. Growth rates were more rapid in the younger than in the older animals. Growth was more rapid in the hind limb than in the forelimb. Growth rates were greater for males than in females. Although this age group represents only two of the 60 or so months necessary for maturity to be reached, oxytetracycline bone-labelling produced results which are more precise than measurements obtained by other methods. This study provides a substantial amount of data for an a...
McLaughlin BG, Doige CE, Fretz PB, Pharr JW.Six foals with angular limb deformities present at birth or shortly after were examined. The limb deformities were caused by abnormalities of the carpal bones and included hypoplasia and osteochondritis dissecans. The 3rd carpal bone was affected most frequently.
O'Brien TR, Hornof WJ, Meagher DM.Subchondral lesions were identified in the distal palmar region of the third metacarpus in 21 fetlock joints of 15 Thoroughbred horses. The lesions were more commonly identified on the lateromedial and flexed lateral projection, with the flexed lateral projection permitting optimal visualization of the lesion. Lesions appeared as poorly marginated, radiolucent defects and were located at the level of the base of the proximal sesamoid bones. The shape and distribution of the radiolucent defects were: crescent, 4; flattened, 4; shallow concavity, 5; deep concavity, 3; oval, 3; and circular, 2. S...
Baker JR, Ellis CE.The causes of death recorded in 480 consecutive post mortem examinations of horses performed at the department of pathology, Veterinary Field Station, University of Liverpool, between February 1958 and February 1980, are reported. The alimentary, locomotor and nervous systems were those most frequently diseased. The most common specific entities were those associated with grass sickness, fractures and endoparasitism.
Arnoldi CC, Reimann I, Mortensen S, Christensen SB, Kristoffersen J, Sønnichsen HV, Smith M.Six metacarpo-phalangeal joints of adult horses were studied. Pressure measurements were made in the joint and the metacarpal bone with simultaneous measurement of the systemic arterial blood pressure. Investigations performed to study the effect of joint position on juxta-articular bone marrow pressure showed that an increase in joint flexion was always followed by a rise in intraosseous pressure with a significant increase at flexion above 60 degrees. Increase in intra-articular pressure which was achieved by injection of saline was always followed by a slower rise in intraosseous pressure. ...
van Veenendaal JC, Moffatt RE.Eight cases of sessile, intra-articular soft tissue masses originating from the cranio-dorsal attachment of the capsule of the fetlock joint of horses are presented. In 4 of these cases an osteochondral fracture of the first phalanx was also present. Clinically the condition closely resembled villonodular synovitis; however the microscopic changes did not correspond to those reported. The clinical signs included lameness after exercise, joint effusion and pain on manipulation. The offending masses were surgically resected and their histology indicated a chronic proliferative synovitis. The res...
Owen RR.Physiologic features of the equine diarthrodial joint and the effects of intra-articular corticosteroid therapy were investigated. It was concluded that intra-articular injection of corticosteroids may be beneficial when lesions are confined to soft tissues of the joint, excluding injuries involving joint laxity. Rest following therapy is important.
Updike SJ, Diesem CD.The vascular supply of the equine stifle joint was investigated, using latex vascular injections of pelvic limbs from 3 adult horses and 6 ponies. Vessels were grossly dissected to the small arteriole level. The primary source of blood supply was the femoral artery and its branches which entered the joint on the caudal and medial surfaces. The superficial vasculature arose from the caudal branch of the deep circumflex iliac artery cranially and laterally, and from the saphenous and descending genicular arteries medially. The deep vasculature arose from the popliteal artery and its branches on ...
Essén B, Lindholm A, Thornton J.Fibre characteristics and enzyme activities were determined for the gluteus, semitendinosus, vastus lateralis and triceps brachii muscles of 55 Standardbred trotters of different ages. Four fibre types (I, IIA, IIB, IIC) were demonstrated by histochemical staining of myofibrillar adenosine triphosphatase after preincubation at different pH values. Type II fibres predominated in all the muscles and the type IIA/IIB ratio was higher in horses over 5 years than in younger horses, except in the vastus in which the IIA/IIB ratio did not change with age. The vastus had the highest proportion of type...
Jeffcott LB.The survey comprised 443 horses, referred to the clinical department of the Equine Research Station, with a history of a thoracolumbar (TL) complaint. A wide range of lesions were capable of producing back problems and more than one condition or site of injury was found in 75 animals (17 per cent). There were 103 horses (19.7 per cent) with no evidence of damage to the TL spine or its associated structures. In 66 of these cases, clinical signs were attributed to a variety of hindlimb lamenesses and, in 37, no specific diagnosis could be made. Soft tissue injury was diagnosed in 203 cases (38.8...
Al-Khalidi NW, Weisbrode SE, Dubey JP.Nine ponies were fed 100,000 infective Toxoplasma gondii oocysts and were given corticosteroid injections before and after feeding the T gondii oocysts. Titers to the Sabin-Feldman dye tests (1:2 to 1:16,384) developed within postinoculation days (PID) 7 to 21 and antibodies persisted to PID 133. Toxoplasma organisms were isolated from the tissues of 4 ponies (heart of 4, brain of 2, spinal cord of 3, diaphragm of 1, skeletal muscle of 1, liver of 1, kidneys of 1) killed between PID 36 and 63, but not from 5 ponies killed between PID 117 and 150. Seemingly, ponies are one of the more resistant...
Henry RW, Diesem CD, Hunter MA, Rankin JS.Eleven ponies were used to perfect a surgical approach to the brachial plexus that would offer maximal exposure to the plexus, with minimal trauma. One pony was euthanatized to determine whether surgical exposure to the plexus was feasible. By approaching the plexus from the prescapular region, the only muscle that was found necessary to incise was the cutaneus omobrachialis. The rest of the procedure required only blunt dissection. In the other 10 ponies, the wounds healed by first intention, and the gait was not affected by the surgery.
Poulos PW.Adequate radiographic evaluation of the horse relevant to purchase examination requires the successful integration of technique, interpretation, and reporting. A thorough knowledge of lameness and disease can be masked by incorrect interpretation resulting from poor-quality films or an incomplete examination. Thus, care must be taken to produce an adequate number of high-quality films on which to base a report, which allows you to describe changes that are present. This information, coupled with your physical examination, other laboratory data, and the knowledge of the expressed use of the hor...
Hjertén G, Drevemo S.Compressions in the forelimb of a horse trotting at 3.7 m/s were studied using high-speed cinematography. From a diagram of shortenings it has been concluded that successive loadings in the longitudinal direction from below signify longer impact time and smaller impact forces compared to a theoretically stiff limb. It is proposed that the limb takes up the impact force passively until the onset of loading at the elbow joint, i.e. 30 ms following first contact.
Turner AS.Congenital and acquired torsion occur in the limbs of domestic animals. Congenital abnormalities are of clinical significance in foals; they are also seen in calves whose dams have ingested certain toxic plants that contain teratogenic agents. Acquired torsional deformities are most common in foals, but are also observed in adult horses, dogs, and llamas. Acquired rotational deformities are almost always associated with angular limb deformities. The clinical consequence of torsional deformities is the early development of degenerative joint disease.
Suwannachot P, Joosten BJ, Klarenbeek A, Hofma J, Enzerink E, van Weeren PR, Everts ME.To investigate the effects of moderate short-term training on K+ regulation in plasma and erythrocytes during exercise and on skeletal muscle Na+,K(+)-ATPase concentration in young adult and middle-aged horses. Methods: Four 4- to 6-year-old and four 10- to 16-year-old Dutch Warmblood horses. Methods: The horses underwent a 6-minute exercise trial before and after 12 days of training. Skeletal muscle Na+,K(+)-ATPase concentration was analyzed in gluteus medius and semitendinosus muscle specimens before and after the 12-day training period. Blood samples were collected before and immediately af...
Kotani H, Taura Y, Sakai A, Tsuka T, Kageyama Y, Nakaichi M.In this study antemortem evaluation of equine flexor tendons--the superficial digital flexor tendon and the deep digital flexor tendon--using magnetic resonance (MR) images was performed. Postmortem flexor tendons were used to prepare the slice positions, coil and body positions for MR imaging. It was possible by this method to take antemortem MR images of equine limbs that distinguished features as well as postmortem images described in previous studies. The total time of antemortem scanning was about 40 min. This study is the first to report antemortem MR images in horses.
Gauvreau GM, Young SS, Staempfli H, McCutcheon LJ, Wilson BA, McDonell WN.A valved gas collection system for horses was validated, then used to examine the relationship between the respiratory exchange ratio (RER), and plasma and muscle lactate in exercising horses. Four healthy Standardbred horses were trained to breathe through the apparatus while exercising on a treadmill. Comparisons of arterial blood gas tensions were made at 3 work levels for each horse, without (control), and with the gas collection system present. At the highest work level, the arterial oxygen tension (PaO2) was significantly lower (P < 0.05), and the arterial carbon dioxide tension (PaCO2) ...
Reinhard F.The conformation of a foal's limbs is of interest beginning in the first days of life. The hoof also must not be neglected. Management and hoof care necessary for normal hoof development are discussed. In addition, pathological hoof shapes and their appropriate treatments are outlined.
Brink P.To describe surgical transposition of the levator labii superioris muscle to treat oromaxillary sinus fistula in horses. Methods: Clinical study. Methods: Three horses with chronic oromaxillary sinus fistula. Methods: After severing its tendinous insertion, the muscle belly of the levator labii superioris muscle was retracted and transposed through the oromaxillary sinus fistula. The tendon exited the oral cavity through a full-thickness buccal incision created adjacent to the oral end of the fistula and was then tunneled subcutaneously in a ventral direction before being anchored by sutures t...
Miller CL, Todhunter R.Osteochondrosis affecting the acetabula in horses is rarely reported. Osteochondrosis dissecans in foals only a few weeks old is also an uncommon finding. Lesions compatible with osteochondrosis dissecans in the acetabulum were found to be the cause of a chronic coxofemoral lameness in a 3-week-old Arabian filly. The history, physical examination findings, joint fluid analysis, gross pathologic and histopathologic findings are described.
McIlwraith CW, Goodman NL.The various conditions of the interphalangeal joint are presented; these include degenerative joint disease and osteochondral chip fractures of the proximal interphalangeal joint, fractures of the middle phalanx affecting proximal and/or distal interphalangeal joints, subluxation and osteochondrosis of the proximal interphalangeal joint, and arthrosis of the distal interphalangeal joint.
Gunson DE.Despite being a very widespread protein, collagen is an unusual molecule possessing a great tensile strength conferred by a rope-like structure and intermolecular crosslinks. Our current knowledge of the biosynthesis of collagen is providing some insights into certain diseases of connective tissue and is also helping us to understand the healing processes of wounds and diseased tissues.
Hornof WJ, Stover SM, Koblik PD, Arthur RM.The research article discusses a study on the use of oblique dorsal views in detecting stress fractures in horses who participate in races. The aim of the researchers was to […]
Kneipp MLA, Sousa LN, Cota LO, Malacarne BD, Winter IC, Santana CH, Santos RL, Xavier ABS, Faleiros RR, Carvalho AM.Coxofemoral dysplasia is a condition characterized by the abnormal development and flattening of the femoral head and deformities in the acetabulum, leading to joint instability. Although described in various animal species, it is uncommon and rarely reported in horses. This article presents a case of incapacitating coxofemoral dysplasia diagnosed in a four-month-old foal Mangalarga Marchador, which exhibited lameness in the hind limbs, thoracolumbar kyphosis, gluteal muscle atrophy, and pronounced sensitivity during pelvic limb flexion. The clinical diagnosis indicative of bilateral coxofemor...
Castro D, Clark-Price S.Pre-existing muscle disorders in horses can often be subtle and may only become evident during or after anesthesia. Advancements in veterinary medicine, along with increased knowledge and research in this field, help minimize anesthesia-related problems. Adequate preanesthesia assessment, early disease diagnosis, and proper management are crucial in minimizing risks to the neuromuscular system during general anesthesia.
Valberg SJ.Although horses most commonly develop exertional rhabdomyolysis, there are numerous causes for nonexertional rhabdomyolysis (nonER) that pose a serious health threat to horses. Their etiologies can be broadly categorized as toxic, genetic, inflammatory/infectious, nutritional, and traumatic and a variety of diagnostic tests are available to discern among them. This study discusses causes of nonER as well as diagnostics and treatments that are specific to each etiology. General treatment of acute rhabdomyolysis is covered in detail in the study in this issue on sporadic and recurrent exertional...
Hopen LA, Colahan PT, Turner TA, Nixon AJ.Subchondral cyst-like lesions of the cubital joint were diagnosed in 7 horses at the teaching hospital between 1983 and 1987. Diagnosis of the lesions was made by administration of intra-articular local anesthesia and/or radiographically. Initial treatment for all horses consisted of stall rest for 60 to 90 days. In addition, 2 horses were administered sodium hyaluronate intra-articularly, 1 horse was given injections of polysulfated glycosaminoglycans IM, and 1 horse was given phenylbutazone orally. Follow-up information was compiled 6 weeks to 4 years after initial examination. At the time o...
McKenzie E.The equine muscle system is complex and prone to a large range of hereditary and acquired diseases that often have overlapping clinical signs with orthopedic, neurologic, and other disorders. Obtaining a clinical history that fully outlines the client concerns and any known information about the disorder and following with a comprehensive physical examination and screening clinical pathology tests are fundamental to achieve definitive diagnosis. A methodical and comprehensive approach aids accurate diagnosis and development of an optimal treatment and management plan. This article describes th...
Finno CJ.In the field of equine muscle disorders, many conditions have a genetic basis. Therefore, genetic testing is an important part of the diagnostic evaluation. Validated genetic tests are currently available for 5 equine muscle disorders: hyperkalemic periodic paralysis, malignant hyperthermia, glycogen branching enzyme disease, type 1 polysaccharide storage myopathy, and myosin heavy chain myopathy. These diseases should be tested for in the appropriate breeds with clinical signs of disease or as part of breeding management. Genetic testing in veterinary medicine is not regulated, and therefore,...
Brommer H, Back W, Schamhardt HC, Rijkenhuizen AB, Barneveld A.To improve fracture treatment, in vitro experiments were performed to study the influence of a full limb cast and a walking cast on the loading regimen of bones in the distal portion of the equine forelimb. Methods: 6 forelimbs of 6 Shetland ponies. Methods: Loading of the third metacarpal bone was considered a representative measure for distal limb loading. Electrical resistance rosette strain gauges were attached to the dorsal, palmar, medial, and lateral surfaces of the midshaft of this bone in 6 forelimbs of 6 Shetland ponies. The limbs were tested in a pneumatic loading device to a maxima...
Lab on a chipMay 28, 2025
Volume 25, Issue 11 2795-2796 doi: 10.1039/d5lc90048d
Heidenberger J, Reihs EI, Strauss J, Frauenlob M, Gültekin S, Gerner I, Toegel S, Ertl P, Windhager R, Jenner F, Rothbauer M.Correction for 'The effect of cyclic fluid perfusion on the proinflammatory tissue environment in osteoarthritis using equine joint-on-a-chip models' by Johannes Heidenberger et al., Lab Chip, 2025, 25, 2256-2269, https://doi.org/10.1039/d4lc01078g.
Dzierzęcka M, Jaworski M, Purzyc H, Barszcz K.The aim of the study was to analyse selected densitometric and geometric parameters in the third metacarpal bone along the long axis in horses. The densitometric parameters included the cortical and trabecular bone mineral density, while the geometric parameters included the cortical, trabecular, and total areas, strength strain index X, strength strain index Y, and the polar strength strain index. Methods: The parameters were analysed using eight sections from 10% to 80% of the length of the bone. Peripheral quantitative computed tomography was used in the study. Statistical analysis was carr...
Ellis KL, Giancola S.Rehabilitation for tendon/ligament injury requires a multimodal approach to reduce pain, restore range of motion, improve proprioception/neuromotor control, and improve strength/endurance. Multiple tools are available to accomplish these goals. The rehabilitation program must be tailored to the individual patient regardless of injury type in order to return the horse to full athletic activity and reduce the risk of reinjury.
Fulton IC, Derksen FJ, Stick JA, Robinson NE, Walshaw R.The efficacy of a nerve muscle pedicle (NMP) graft in restoring upper airway function was evaluated in exercising horses with induced left laryngeal hemiplegia. The NMP graft was created from the first cervical nerve and the omohyoideus muscle and transplanted into the left cricoarytenoideus dorsalis muscle. Seven adult Standardbreds were trained to exercise on a treadmill inclined at 6.38 degrees. With the horses at rest and exercising at 4.2 and 7.0 m/s, the following variables were recorded: peak inspiratory and expiratory transupper airway pressures (defined as the pressure difference betw...
Campana S, Dittmann M, Kircher P, Donati B.The distribution pattern of central tarsal bone (CTB) changes has not been described, except for slab- and dorsomedial-plantarolateral fractures. Objective: To describe CTB changes in CT and document their distribution and associations. Methods: Retrospective case series. Methods: Standing and recumbent tarsal CT studies from 94 clinical cases were retrospectively evaluated. General case information, degree of sclerosis (none-severe), lesions (demineralisation, cystoid, fissure/fracture) and their location were recorded, dividing CTBs into 8 regions. Results: Eighty five of 94 tarsi showed at ...
Jenner F, Edwards RB, Voss JR, Southwood L, Markel MD, Richardson DW.To evaluate the use of hydrothermal ablation of articular cartilage for arthrodesis in horses through investigation of the effects of joint lavage with physiologic saline (0.9% NaCI) solution (80 degrees C) for various treatment times on chondrocyte viability in the articular cartilage of the metacarpophalangeal and metatarsophalangeal joints of cadaveric horse limbs. Sample Population-7 pairs of metacarpophalangeal and 8 pairs of metatarsophalangeal joints from 8 Thoroughbreds. Methods: The horses were euthanatized for reasons unrelated to musculoskeletal disease. On a random basis, 1 joint o...
Asperio RM, Marzola P, Sbarbati A, Osculati F, Addis F.To analyze the tendon of the deep digital flexor (TDDF) muscle of the forelimb in horses by use of a contrast radiographic agent (gadopentate dimeglumine [Gd-DTPA/Dimeg]) and magnetic resonance imaging (MRI) and to determine the concentration of water protons in the tendons by use of MRI. Methods: 8 TDDF harvested from the forelimbs of 6 horse cadavers. Methods: Examinations were performed on the same portion of each tendon. Tendons were examined by use of two techniques: MRI before and after treatment with Gd-DTPA/Dimeg as well as scanning electron microscopy. Results: Tendons did not have de...
Clayton HM.The horse's head and neck account for about 10% of body weight, and this, combined with the fact that they are cantilevered in front of the trunk, produces considerable leverage around the joints at the base of the neck. During locomotion, the neck is moved primarily by gravitational and inertial forces controlled by eccentric-concentric cycles of contraction in the topline muscles assisted by energy-saving, stretch-recoil cycles in the nuchal ligament. The functional part of the nuchal ligament is the caudal funicular region and the lamellae to the second cervical vertebra that acts as the po...
Dzierzecka M, Czerwinski E.On the basis of a digital analysis of radiograms it was checked if, and to what extent, the extended loading of one of the sides of the body of racehorses leads to differences in the microstructure of the spongy bone of the bilateral pastern bones of the thoracic limbs. The research material consisted of radiograms of the pastern bones of the right and left thoracic limbs of racehorses. On the basis of computer image radiological analysis with the use of the "Trabecula,, programme, a quantative evaluation of the structure of the spongy bone of the pastern bones was conducted. It was noted that...
