Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Musculoskeletal System
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.
Diagnostic techniques for identification and documentation of tendon and ligament injuries. Conventional clinical examination remains of medical and economic value for diagnosis of soft tissue injuries in the equine athlete. This procedure requires concentration and rigor to establish the diagnosis, and, if possible, some experience to better evaluate the prognosis. None of the new imaging techniques can replace the physical examination, but each may provide additional information. These sophisticated methods are bringing considerable progress in the knowledge of locomotor injuries in the horse and a tremendous improvement in our ability to diagnose precisely lamenesses and limitatio...
The pathobiology and repair of tendon and ligament injury. Injury of the collagenous structures comprising tendons and ligaments, either from acute trauma or from repetitive strain lesions, results in protracted periods of disability. The resolution of such injuries often fails to restore the normal morphologic and functional characteristics of the structure and, therefore, either compromises the future performance of the individual or predisposes to an increased risk of recurrent injury.
Congenital abnormalities of tendons and ligaments. Congenital deformities of tendons and ligaments are not uncommon in foals. The vast majority of hyperextension deformities are treated successfully with exercise management and extended heel shoes. Successful treatment of contractural deformities depend on the site and severity of the deformity and on the appropriate use of medical, physical, and, possibly, surgical therapy.
Functional anatomy of tendons and ligaments in the distal limbs (manus and pes). Tendons and ligaments of the equine distal limbs have a prominent anatomic, functional, and clinical importance. This article reviews the descriptive and topographic anatomy of these structures in details. Special information is given about the mechanical properties and functional anatomy of the flexor tendons, accessory ligaments, and third interosseous muscle, as well as about their roles during the standing position and gaits.
Superior check ligament desmotomy for treatment of superficial digital flexor tendonitis in thoroughbred and standardbred horses. Bilateral superior check ligament desmotomy was performed on 31 Thoroughbred and 17 Standardbred horses as the sole method of treatment for superficial digital flexor tendonitis. Horses resumed racing between 6 and 19 months after surgery. Horses that were able to compete in 5 or more races without injury to the tendon again were considered to have had a successful return to racing. Twenty-five Thoroughbreds were suitable for later study and 13 of these (52%) raced on 5 or more occasions. Fifteen Standardbreds were suitable for later study and 10 of these (66%) raced on 5 or more occasions. Wi...
Practical management of superficial digital flexor tendinitis in the performance horse. The authors of this section represent a broad range of practice experience with horses that perform in rigorous and varied sport competitions. Each breed and performance application represent unique challenges of diagnosis and uncompromising demands on rehabilitated tendon injuries. This article will serve to guide, stimulate, and encourage veterinarians to apply scientific criteria to the evaluation of tendinitis therapy in the years to come so that we can arrive at a more valid consensus as to the "best" means of tendon and ligament injury management.
Treatment of superficial digital flexor tendinitis. This article reviews the research and clinical findings relevant to the treatment of acute tendinitis in the horse. The goals of treatment are to reduce inflammation, minimize scar tissue formation, and promote restoration of normal tendon function. A wide variety of treatments have and still are being used to treat tendinitis, which indicates that there is no uniformly successful way to return a horse to full athletic function after injury. Therapy depends on the severity of tendinitis and duration of injury and can be divided into treatment during the inflammatory, repair, and maturation pha...
Denervation atrophy in three horses with fibrotic myopathy. Three horses with fibrotic myopathy were examined for neuromuscular disease. In 2 horses, concentric needle electromyography was performed. Dense spontaneous activity suggestive of denervation, was found in multiple thigh muscles of 1 of the 2 horses. All 3 horses were euthanatized. Histochemical and histologic examination of tissue specimens was performed. All horses had degenerative lesions in peripheral and intramuscular nerves. Angular atrophy of type-1 and type-2 muscle fibers, indicative of denervation atrophy, was seen in multiple muscle specimens from all 3 horses. One horse was found ...
Differential scanning calorimetric studies of superficial digital flexor tendon degeneration in the horse. Differential scanning calorimetry (DSC) of equine superficial digital flexor tendons revealed the presence of a small exothermic peak at 23 degrees C of unknown origin, and a large endothermic peak at 70 degrees C due to denaturation of cross-linked collagen fibres. In the central degenerated core of damaged tendons the denaturation temperature remained at 70 degrees C but the enthalpy decreased in relation to the extent of degeneration of the tendon. We suggest that this reduction in enthalpy is due to depolymerisation and denaturation of the collagen fibres. This contention is supported by t...
Arthroscopic removal of osteochondral fragments from the proximal interphalangeal joint of the pelvic limbs in three horses. Osteochondral fragments detected in the proximal interphalangeal joint in the pelvic limbs of 3 horses (2 Standardbreds and 1 Thoroughbred) caused joint enlargement and lameness. Fragments were removed by use of arthroscopy. Accurate placement of the arthroscope into the dorsal joint space was necessary to obtain an adequate view of the fragments. After surgery, 2 of the horses resumed racing without joint problems, and the third was in training to race. High-detail radiographs are necessary to detect osteochondral fragments in horses with joint enlargement or lameness localized to the proxima...
Bilateral tibial metaphyseal stress fractures associated with physitis in a foal. A 7-month-old Appaloosa foal had bilateral hind limb lameness and was unable to rise from recumbency without assistance. Lameness could be exacerbated by tarsal flexion and a firm swelling at the distomedial aspect of the tibias was associated with a marked pain response when palpated. Radiography revealed enlargement of the distal tibial metaphysis physis (compared with normal), and radiolucent fissure lines extending proximally from the physis into the metaphysis at its medial aspect. Treatment included rest and dietary adjustment. Although clinical signs initially resolved following treatme...
In vitro mechanical properties and failure mode of the equine (pony) cranial cruciate ligament. In vitro failure modes and mechanical properties of the equine cranial cruciate ligament (CCL) were evaluated in 15 stifle joints from 10 ponies. Ponies were from 3 to 25 years of age and weighed from 122 to 208 kg. Femur-CCL-tibia specimens were mounted in 48 degrees of flexion, distracted until a 500-g tensile preload was achieved, and then tested by tensile loading to failure. Specimens failed by complete midsubstance CCL rupture (n = 9), combined tibial insertion avulsion fracture and midsubstance CCL rupture (n = 4), and combined femoral origin avulsion fracture and midsubstance CCL ruptu...
Skeletal muscle characteristics in red blood cell normovolaemic and hypervolaemic standardbred racehorses. Muscle biopsy specimens from the middle gluteal muscle were studied in 16 red blood cell hypervolaemic (Group HV) and 19 normovolaemic (Group NV) Standardbred racehorses. All horses were stallions, 4-8 years old and having similar mean racing performance values, as described by an individual selection index value. All horses raced regularly but those in Group HV did not perform as expected and were therefore referred to the clinics for exercise tolerance testing. Muscle biopsy specimens were analysed for fibre type distribution (Type I, IIA and IIB), fibre area and relative fibre area. In addi...
Causes of death in racehorses over a 2 year period. Necropsies were performed on 496 horses that had a fatal injury or illness at a California racetrack during the period February 20th 1990 to March 1st 1992. The primary cause of death was categorised by breed, activity at time of injury or illness and organ system affected. Most of the submissions were Thoroughbred horses (432) and Quarter Horses (46). Most of the injuries occurred while racing (42%) and in training sessions (39%); with fewer non-exercise (12%) and accident (7%) related injuries or illnesses. Musculoskeletal injuries accounted for 83% of the Thoroughbred and 80% of the Quarter...
Exercise-induced hyperthermia as a possible mechanism for tendon degeneration. Mathematical modelling of tendon thermodynamics predicted that the temperature of the central core of the equine superficial digital flexor tendon would plateau at 11 degrees C above the tendon surface temperature during a sustained gallop. A mean temperature differential (between tendon core and surface) of 5.4 (S.E. +/- 1.0) degrees C was demonstrated in vivo in four horses. Peak intra-tendinous temperatures in the range 43-45 degrees C were recorded. Temperatures above 42.5 degrees C are known to result in fibroblast death in vitro [Hall (1988) Radiobiology for the Radiologist, 3rd Edn., pp...
An in vitro biomechanical investigation of an interlocking nail for fixation of diaphyseal tibial fractures in adult horses. The compressive, bending and torsional mechanical properties of osteotomized adult equine tibiae stabilized with an interlocking intramedullary nail (nail-tibia composite) were compared with those of intact tibiae to determine the clinical applicability of the the nail for repair of tibial fractures in adult horses. The mean yield load, failure load, and stiffness for the nail-tibia composites were significantly less (P < .05) than those for the intact tibiae in all loading configurations. The mean compressive yield load for the nail-tibia composites was greater than the compressive load ca...
Carpal conformation in relation to carpal chip fracture. An objective radiological method of assessing the degree to which horses are conformationally 'back at the knee' (hyper-extended) is described. The effects on the measurements of variations in the direction of the incident X-ray beam and variations in weight bearing by the horse were assessed. A change from a lateromedial projection towards a plamaro-lateral-dorsomedial oblique projection consistently tended to reduce the observed degree of hyperextension of the carpus. Raising the contralateral limb to increase the load on the carpus had little effect on the measurements. The carpi of 21 thor...
Bilateral hind limb hypoplasia in a foal. Hypoplasia affecting both hind limbs was observed in a neonatal foal. Scintigraphy aided in establishing diagnosis and prognosis. Radiography revealed an abnormally shaped middle phalanx and lack of the distal phalanx and navicular bone in the right hind limb, with an abnormally shaped distal phalanx and navicular bone in the left hind limb. Scintigraphic findings were closely correlated with the radiographic findings. Radiographic and scintigraphic findings were confirmed at postmortem examination.
Effect of exercise on hexokinase distribution and mitochondrial respiration in skeletal muscle. Horses were subjected to treadmill running at 65% (submaximal) or 100% (maximal) VO2,max to examine the effects of exercise on subcellular distribution of hexokinase (HK) and on mitochondrial respiration. It is hypothesized that the fraction of HK bound to mitochondria will be reduced due to an elevation of glucose-6-phosphate (G-6-P) concentration in the exercising muscle and that such release of HK from mitochondria will depress oxidative phosphorylation. Changes in muscle G-6-P concentration, pH, subcellular HK distribution, mitochondrial respiration and other metabolites were determined in...
Avulsion fracture of the origin of the extensor digitorum longus muscle in a foal. A 9-week-old Thoroughbred x Holsteiner colt was referred for evaluation and treatment of lameness of the right hind limb. Radiography of the stifle revealed multiple bony fragments within the lateral portion of the femorotibial joint and a radiolucency of the distolateral portion of the femur in the area of the extensor fossa, which were consistent with avulsion of the origin of the extensor digitorum longus muscle. Arthroscopy of the lateral portion of the femorotibial joint revealed exposed subchondral bone in the area of the extensor fossa, and the origin of the extensor digitorum longus mu...
Causes of and farm management factors associated with disease and death in foals. A prospective study was conducted to describe the causes of and farm management factors associated with disease and death in a population of foals in Texas. Data from 2,468 foals at 167 farms were provided by veterinarians for all 12 months during 1991. Among 2,468 foals, 116 deaths were reported (4.7%). Pneumonia was the most commonly reported cause of death, followed by septicemia. When considered as a group, musculoskeletal disorders (traumatic, infectious, or deforming problems) represented the most common cause of all reported deaths. Daily risk of death was greatest during the first 7 da...
Sir Frederick Hobday Memorial Lecture. Some observations on condylar fractures of the third metacarpus and third metatarsus in young thoroughbreds. The common spontaneous fractures of the third metacarpus and
metatarsus of young racehorses are split cannons or condylar
fractures. Meagher (1976) described a series of 45 cases involving
the lateral condyle and Richardson (1984) detailed 15 cases involving
the medial metatarsal condyle. Rick et al. (1983) published a clinical
and pathological study of 75 cases of third metacarpal and metatarsal
condylar fracture. In the United Kingdom, Barr et al. (1989) recorded
8 cases with long fractures, 3 lateral and 5 medial condylar. This
paper reports 124 cases of medial or lateral condylar f...
Repair of fractures of the distal aspect of the radius in two horses. Fractures of the distal radius in two horses were repaired by open reduction and interfragmentary compression using screws placed in a lag fashion. One horse had a complete oblique fracture of the medial aspect of the epiphysis of the distal radius and was sound for riding 32 months after surgery. The other horse had an open spiral comminuted fracture with medial displacement of the distal radial fragment. Laminitis developed in the contralateral limb and this horse was euthanatized 5 weeks after surgery.
Avulsion of the origin of the peroneus tertius tendon in a foal. A 3-month-old foal was examined because of lameness and fracture of the left lateral trochlear ridge of the femur. Arthroscopy of the left femoropatellar joint was elected. After induction of general anesthesia and placement of the foal in dorsal recumbency, it was noticed that the left hind limb was extended at the tibiotarsal joint and flexed at the femorotibial joint. Avulsion fracture at the origin of the peroneus tertius tendon was diagnosed. Fracture fragments were excised. The horse had mild left hind limb lameness at the time of follow-up evaluation 1 year after discharge.
