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.
Collins EA.Four cases of equine lameness were treated with intra-articular polysulphated glycosaminoglycan. Two, two-year-old flat racers were treated conservatively after traumatic injury. They subsequently became lame owing to the formation of new bone and osteophytes. Two older steeplechasers were lame owing to degenerative joint disease. The four horses were treated with intra-articular injections of polysulphated glycosaminoglycans and, after three or four injections, they became clinically sound and were able to continue racing with varying degrees of success.
Bollwein A, Hänichen T.The cervical vertebral column of 103 horses of different age (42 weeks old fetus to 23 years) were examined with respect to age-related changes of the intervertebral disks. On gross examination the cervical intervertebral disks in the horse miss a pulpy nucleus but consist of a fibrocartilaginous tissue only, which is in contrast to literature. Age-related degenerative lesions as disintegration of connective tissue fibers leading to partial or complete loss of connection between the disks were found. In the more severe cases a yellow discoloration of the separated disks could be seen. Incidenc...
Meijer AE, van den Hoven R, Wensing T, Breukink HJ.In this communication, the results of an enzyme histochemical study on m. gluteus medius of horses, sensitive to exertional myopathy, during attacks of rhabdomyolysis are presented. The activity and location of about 25 enzymes were examined. In the present report, the early metabolic changes are discussed. Within 6 min after an attack, some large rounded fibres (approximately 2%) were seen, which showed an intense red staining in the haematoxylin and eosin sections. These hypercontracted fibres showed an increase in activity of mitochondrial adenosine triphosphatase, indicating the presence o...
van Suntum M, Hartung K.Subchondral bone cysts or cyst like lesions are an important hint in the radiographic diagnosis of degenerative joint disease. In this study we set artificial lesions of different size in the subchondral bone of different joint surfaces of horses, and we then tried to determine from which size on these lesions could be made visible on radiographs in different projections. It shows that the possibility of visualization of such lesions is frequently overestimated, cyst like lesions have to be quite large, before they can be seen on routine radiographs.
Nishita T, Matsushita H.Sections of equine thymus were examined for the presence of carbonic anhydrase (CA) isozymes by an immunohistochemical method. Carbonic anhydrase III, a major enzyme of skeletal muscle, was localized in some of the epithelial-reticular cells of the equine thymus. This finding suggests the presence of a new type of cell in the thymic cortex. The concentration of CA-III in the thymus was 17 micrograms/g wet tissue. CA-I and CA-II were not found in equine thymus.
Durchfeld B, Rüdiger J.Bilateral rupture of the musculus longus capitis from the tuberculum musculare of the os occipitale and of the musculus rectus capitis ventralis from the os occipitale combined with a synchondrolysis of the synchondrosis sphenooccipitalis in a 17 months old thoroughbred stallion is reported.
Nunamaker DM, Butterweck DM, Provost MT.Geometric properties of the third metacarpal bone were compared between the young and adult Standardbred and Thoroughbred racehorse. The change in shape during growth and superimposed training was dramatic in both breeds but the Thoroughbred showed the greatest difference in the minimum moment of inertia as the animal matured. Males had larger moments of inertia throughout the length of the diaphysis than did females. The differences in geometric properties of the third metacarpal bone between the Thoroughbred and Standardbred were related to the incidence of fatigue fractures which are common...
Gasthuys F, Vandamme R, De Moor A, De Meurichy W.A commercial neuroleptanalgesic acepromazine-etorphine combination administered intramuscularly to four horses produced a severe tachycardia and an increase in muscular tone, together with hypoxaemia, hypercapnia, metabolic acidosis associated with an increase in the packed cell volume and hyperglycaemia. No electrolyte changes were found. After reversal of the action of etorphine with diprenorphine, there was a prolonged decrease in the calcium and phosphorus serum concentrations and decreases in the packed cell volume and the total protein serum concentration. In a second experiment on the s...
Colles CM.This paper describes the application of foil strain gauges to the hoof wall, and the use of measuring equipment to monitor weightbearing and changes in hoof shape in shod and unshod horses. It concludes that the systems can detect hoof movement and that results are reproducible. It is also concluded that the use of a conventional nailed on iron shoe restricts flexion and spreading of the hoof wall at the ground surface, but has little effect on the degree of expansion of the heels of the foot.
van den Bogert AJ, Schamhardt HC, Crowe A.Locomotion of the horse is simulated using a mathematical model based on rigid body dynamics. A general method to generate the equations of motion for a two-dimensional rigid body model with an arbitrary number of hinge joints is presented and a numerical solution method, restricted to tree-structured models, is described. Joint movements originating from muscular forces or moments are simulated, but the method also allows that parts of the model follow strictly the pattern of kinematic data. Moment-generators with first-order linear feedback were used as a rotational muscle-equivalent. Ground...
Verschooten F, Roels J, Lampo P, Desmet P, De Moor A, Picavet T.Radiographic measurements from the lateromedial projection of the equine foot were compared in three groups of horses. Group 1 consisted of 143 normal horses, group 2 were 60 horses with clinical navicular disease and group 3 were 161 horses with clinical and radiographic navicular disease. Several measurements tended to be larger in group 3 than group 1. An enlargement of the navicular bone was observed in proximodistal and dorsopalmar directions. Partial enlargement of the pedal bone was observed in groups 2 and 3. Few differences were observed between age classes. All horses aged four years...
Kobluk CN, Schnurr D, Horney FD, Sumner-Smith G, Willoughby RA, Dekleer V, Hearn TC.High-speed cinematography with computer aided analysis was used to study equine hindlimb kinematics. Eight horses were filmed at the trot or the pace. Filming was done from the side (lateral) and the back (caudal). Parameters measured from the lateral filming included the heights of the tuber coxae and tailhead, protraction and retraction of the hoof and angular changes of the tarsus and stifle. Abduction and adduction of the limb and tarsal height changes were measured from the caudal filming. The maximum and minimum values plus the standard deviations and coefficients of variations are prese...
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.
Lagier R.Spinal hyperostosis, an anatomical and radiological concept primarily described in man, is characterized by enthesopathic bony overgrowth on vertebral bodies in the form of spurs or intervertebral bridges. It can also be part of a more diffuse enthesopathic condition, including the appendicular skeleton. These changes are distinct from those of osteoarthrosis. Similar changes can be observed in all kinds of mammals, independent of their type of locomotion (bipodic, quadrumanous, quadrupedic, or aquatic). An anatomical and radiological study is presented of six cases (with histological examinat...
Meijer AE, van den Hoven R, Wensing T, Breukink HJ.Needle biopsies from m. gluteus medius of 22 horses which had suffered from repeated attacks of exertional myopathy were studied at various times after an attack, to determine if metabolic alterations can be demonstrated by enzyme histochemistry. Morphological changes and activity of 25 enzymes were studied. Immediately after onset of an attack, some large rounded fibres with a defect of the oxidative phosphorylation were seen. After some hours these fibres lost their glycolytic enzyme activity, followed by disappearance of mitochondrial enzyme activity with accumulation of Ca2+-containing sub...
Ford TS, Ross MW, Orsini PG.To study communications and boundaries of the middle carpal and carpometacarpal joints of the horse, 50 forelimbs were obtained from fresh cadaver specimens. Blue latex solution (20 +/- 2.5 ml) was injected into the middle carpal joint, and the specimens were frozen in extension. Frozen specimens were cut into 1-cm sagittal sections from the middle of the radius to the middle of the metacarpus. The communications between the middle carpal and carpometacarpal joints and the presence, length, and position of the distopalmar outpouchings of the carpometacarpal joint were recorded. The middle carp...
Kayar SR, Hoppeler H, Mermod L, Weibel ER.Individual mitochondria were reconstructed from ultrathin serial sections of selected muscle fibers in the M. semitendinosus of a horse, over a length of nearly two sarcomeres. Mitochondria were found to be highly variable, with size and complexity of single mitochondria increasing with the fractional part of a fiber occupied by mitochondria. In fibers with a mitochondrial volume density of less than 4%, corresponding to the mitochondrial content of fast-twitch glycolytic fibers, mitochondria were generally rather simple cylindrical shapes, oriented parallel to the myofibrils. In fibers with a...
Strain GM, Taylor DS, Graham MC, Kamerling SG.Cortical somatosensory-evoked potentials (SEP) were recorded from thoracic and pelvic limbs in 15 horses (13 Thoroughbreds and 2 Quarter Horses). Ulnar nerve SEP were evoked by electrical stimulation of the lateral palmar branch of the ulnar nerve at the level of the metacarpophalangeal joint. Recordings were taken between electrodes at 2 cm lateral to the vertex (contralateral to the stimulated limb) and the midpoint of the interorbital line. Four peaks were found in all recordings: N1, P1, N2, and P2. Latencies to the peaks were 39.0 +/- 2.7, 45.5 +/- 5.3, 50.4 +/- 5.2, and 62.3 +/- 3.7 ms (...
Clem MF, DeBowes RM, Douglass JP, Leipold HW, Chalman JA.The effects of radioulnar fixation were studied in 21 Quarter horse foals by applying a bone plate to the caudal aspect of the proximal part of the ulna, with screws engaging both the radius and the ulna. The plates were applied at 1 month of age in six foals (group I), 5 months of age in six foals (group II), and 7 months of age in three foals (group III). Six foals underwent sham operations at 1 month of age to serve as controls (group IV). Ulnar dysplasia and elbow subluxation developed in all treated foals. The magnitude of ulnar dysplasia was inversely related to the patient's age at fixa...
Mäenpää PE, Pirskanen A, Koskinen E.Serum alkaline phosphatase activity and serum concentrations of osteocalcin, free thyroxine, protein, and cholesterol were measured in 14 foals monthly from birth to 1 year of age. A transient decrease (P less than 0.05) in alkaline phosphatase activity and osteocalcin, free thyroxine, and cholesterol concentrations was found in November after transferring the horses from pasture to stables for the winter months. During the 2 subsequent months, serum alkaline phosphatase activity and osteocalcin concentration increased slightly. Protein concentration was highest in late fall and decreased (P l...
Specht TE, Nixon AJ, Colahan PT, Moore BG, Brown MP.Four horses with subchondral cyst-like lesions in the medial radial facet of the distal portion of the radius were examined. Joint effusion and signs of pain from flexion of the antebrachiocarpal joint were not observed, but lameness was observed in 3 of the 4 horses. Regional nerve blocks and intra-articular anesthesia were used to localize the lesions, and conservative treatment resulted in soundness for performance.
Bertoti DB.The purpose of this study was to measure postural changes in children with spastic cerebral palsy after participation in a therapeutic horseback riding program. Eleven children with moderate to severe spastic cerebral palsy, aged 2 years 4 months to 9 years 6 months, were selected for this study and underwent postural assessments according to a repeated-measures design. Assessment of posture was performed by a panel of three pediatric physical therapists, using a postural assessment scale designed by the author. A composite score for each test interval was calculated for each child, and a medi...
Thompson KN, Jackson SG, Baker JP.Effects of high dietary levels of energy, protein and Ca and deficient levels of Ca on skeletal growth and development in the equine were studied in two experiments. The weanlings were fed grain-based diets. In Exp. 1, Group 1 (Ctl) received all nutrients at NRC recommended levels for growth; Group 2 (HE) received 150% of their digestible energy (DE) requirement; Group 3 (LC) received 150% of DE and 35% of Ca requirements. In Exp. 2, Group 1 (Ctl) again received all nutrients at NRC recommended levels for growth; Group 2 (HEP) received 150% of DE and 275% of CP requirements; Group 3 (HEPC) rec...
De Auer , Ng JC, Seawright AA.The copper and zinc concentrations in the blood of stabled thoroughbred horses and in Australian Stock Horses mares at pasture, either late pregnant or lactating were determined by an atomic absorption spectroscopic method. The plasma concentration of the trace elements in these apparently normal horses were generally below the "normal" range. The plasma copper, caeruloplasmin copper, whole blood copper and plasma zinc concentrations in the stabled thoroughbreds were 0.76 +/- 0.19 micrograms/ml (n = 82), 0.56 +/- 0.14 micrograms/ml (n = 83), 0.75 +/- 0.18 micrograms/ml (n = 82) and 0.47 +/- 0....
Losonsky JM, Kneller SK.Bilateral metacarpophalangeal radiographs of 100 Standardbreds were examined for visualization and location of nutrient foramina of the proximal phalanx. Foramina were located in the dorsal or palmar cortex or were not visible radiographically. Of 100 horses, 45 had bilaterally symmetrical foramina. Left and right proximal phalangeal foramina were asymmetrical in the remaining 55 horses. Of 200 proximal phalangeal foramina (in 100 horses), 78 were in the dorsal cortex, 61 were in the palmar cortex, and 61 were not visible radiographically. A significant (P = 0.05) effect of age or sex could no...
Bukowiecki CF, Sanders-Shamis M, Bramlage LR.Medial collateral ligament ruptures in horses are rare and difficult to treat. Conservative treatment usually results in degenerative joint disease that causes permanent lameness. Surgical treatment may be an alternative for salvaging horses for breeding purpose.
McCarthy PH.A detailed description is given of the structures forming the borders of Viborg's triangle and those structures contained within and adjacent to the triangle. Changes in the size, shape and prominence of these structures with changes of head and neck posture of the horse are also described.
Forterre F, Stoffel MH, Koch C, Precht C, Waschk M, Bürki A.Atlantoaxial instability has been reported in humans, dogs, equids and ruminants. The functional role of the atlantoaxial ligaments has only been described rudimentarily in equids and ruminants. The goal of the present cadaveric study was to compare the anatomy between the different species and to comparatively assess the role of the stabilizing ligaments of the atlantoaxial joint under sagittal shear loading in canine, equine, and bovine cervical spines. Methods: Three equine, bovine, and canine cadaveric specimens were investigated. Biomechanical testing was performed using a purpose built s...
van Gurp M, Schamhardt HC, Hartman W, Crowe A.A dynamic model is developed to describe the swing phase of the hindlimb of a normally walking horse. The limb was represented by four rigid segments constrained to move in a sagittal plane only. The mathematical equations of motion of this four-element pendulum were formulated using Lagrange's theorem. The morphometric parameters from the hindlimb segments of 3 horses were determined using high-speed film analysis. Five muscle groups were incorporated in the model. Muscle activity was derived from earlier EMG measurements. Optimization of muscle moments resulted in a simulated swing movement ...
Collard XR, Danse EM, Rombouts JJ.The treatment of acute complete (grade III) tears of the lateral ligaments of the ankle has generated much controversy in the medical literature. Functional treatment has become the standard treatment as it has been shown that there is no significant difference in long term results whatever the treatment (operative repair and cast, cast alone, or early controlled mobilization). Functional treatment includes only a short period of protection by tape bandage or brace and allows early weight-bearing. Major trauma with avulsion of bone and severe ligamentous damage on both medial and lateral sides...
Gaul CE, Rich AF, Ressel L, Hinnigan GJ, Owen KR.This study aimed to determine whether a true synovial structure exists over the olecranon tuberosity, which could be attributed to a noninflamed olecranon bursa. Contrast radiography, gross anatomical dissection, and histopathology were used to evaluate the olecranon bursa in horses with no previous elbow pathology. The radiographic study revealed that the contrast was positioned subcutaneously, superficial to the long head of the triceps and its insertion on the olecranon tuberosity and did not extend cranial to the triceps tendon. The contrast region was consistent in shape, size, and locati...