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.
Denny HR, Barr AR, Waterman A.A series of 25 horses with olecranon fractures are reviewed. Twenty-one cases were treated surgically by the application of a tension band plate to the caudal aspect of the ulna. Seventy six per cent of these regained full limb function. The results of treatment are compared with two other series of conservatively and surgically treated cases.
Sullins KE, McIlwraith CW.Transverse or oblique midshaft tibial osteotomies were created in 11 foals. The osteotomies were repaired during the same procedure using external skeletal fixation in either full splint or 3-dimensional (3-D) tent configurations. Four of the six foals receiving the full splint fixator recovered to full soundness; two were euthanized because of complications. The foals receiving the 3-D tent configuration would not bear weight on the limbs and consequently suffered significant secondary fracture disease. These foals were euthanized for humane reasons before the scheduled termination of the pro...
Fischer AT, Stover SM.Third carpal sagittal fractures were found to be related to racing injuries in 10 of 12 horses. These fractures occurred most commonly on the medial aspect of the bone. A dorsoproximal-dorsodistal view of the carpus was required to visualize the fracture in all cases. Healing of the fracture required periods of rest of up to one year. Conservative management of these fractures resulted in return to function in 7 of 12 horses.
Dik KJ, Merkens HW.Eleven horses with unilateral distension of the sheath are reported with emphasis on the use of plain and contrast radiography in diagnosis. Six had associated bony abnormalities of the sustentaculum tali, and two of these showed destructive or mixed destructive and proliferative lesions resulting from osteomyelitis. One horse had a fracture of the sustentaculum. In three horses proliferative changes were found. Bony changes were best demonstrated on a dorsomedial-plantarolateral oblique view. Contrast radiography of the tarsal sheath was performed in five cases without, and two horses with, a...
Bertone AL, McIlwraith CW.Arthroscopic approaches to the scapulohumeral joint were developed in four clinically normal, live horses (5 limbs) to determine their usefulness for evaluation and potential surgical treatment of intraarticular lesions. The articular surface of the entire glenoid, cranial humeral head (medial and lateral) and caudolateral humeral head, as well as the synovial membrane, could be closely examined from an arthroscopic portal cranial to the infraspinatus tendon. The caudomedial humeral head could be examined partially. Cranial and caudal instrument portals allowed good surgical access to the enti...
Cahill JI, Goulden BE.Recent research on the muscular and nervous changes which occur in idiopathic equine laryngeal hemiplegia has indicated that many of the traditional concepts of the aetiology of this disease are erroneous. In light of the new knowledge gained, the various predispositions and possible causes of laryngeal hemiplegia are discussed, and it is suggested that the underlying mechanism of axonal damage in this neuropathy of horses may be related to abnormal energy metabolism in the axon.
Manohar M, Gustafson R, Nganwa D.Effects of 1.55 minimum alveolar concentration isoflurane O2 anesthesia (2.03% end-tidal isoflurane) on blood flow in the up-(nondependent) and down-(dependent) positioned skeletal muscles were studied at 60, 120, and 180 minutes in 6 healthy isocapnic ponies in right lateral recumbency on a nonpadded hardwood floor. Measurements were made, using 15-micron diameter radionuclide-labeled microspheres injected into the left ventricle, and comparisons were made with data obtained from ponies in the conscious state. Isoflurane administration caused a sharp reduction in cardiac output and systemic p...
May SA, Wyn-Jones G.The use of markers placed over the tuber coxae on each side of a horse to aid identification of the relative movement of these structures at the trot, for teaching and research purposes, is described. In each case of hindleg lameness studied, the tuber coxae on the lame side showed a consistent increase in vertical displacement relative to that of the contralateral limb, and a characteristic pattern of movement throughout the stride irrespective of the site or cause of pain.
Leach DH, Sprigings EJ, Laverty WH.Standard univariate and bivariate statistical methods and two multivariate methods, stepwise regression and factor analyses, were used to analyze 17 stride-timing measurements of 22 racing Thoroughbreds filmed at the beginning of races. All horses were in a right-lead transverse gallop. Data were extracted from frame-by-frame analysis of 16-mm film taken with a high-speed camera. The mean stride duration was 0.405 s and the mean stride frequency was 2.47 strides/s. Stride duration had a higher correlation to the suspension-phase duration (r = 0.864) than to stride-stance-phase duration (r = 0....
Pintea V, Ganţă C.The mm. lumbricales and the mm. capsulares of the shoulder and hip joints of the horse are rich in neuromuscular spindles (NMS). The mm. interossei of the pig, but not of the horse, have NMS too. In the m. orbicularis of the eye, m.hyo-epiglotticus and the m. palatinus of the horse NMS are absent. In the vestigial muscles, as m. extensor digitorum brevis and m. of Thiernesse, NMS are absent too. A role of modulator for the proximal muscles of the limbs by the distal muscles is hypothesized, as well as the absence of NMS in striated muscles not involved in locomotion.
Kelso TB, Hodgson DR, Visscher AR, Gollnick PD.Several biochemical components of the white portion of the gastrocnemius (WGM), plantaris (PM), and soleus (SM) muscles of the rat and middle gluteal (MGM) muscle of the horse were compared based on wet and dry weight, protein, and total creatine concentrations ([TCr]). The water content was similar for the rat hindlimb muscles, however, the concentrations of protein, ATP, phosphocreatine (PCr), creatine, and glycogen ranked as SM less than PM less than WGM for all reference bases except total creatine. In contrast, concentrations of ATP, creatine, and PCr were similar in all muscles studied w...
Bukowiecki CF, Bramlage LR, Gabel AA.Forty-eight limbs of 12 freshly euthanized horses were used to generate data on the strength of the equine suspensory apparatus. The point of failure of the suspensory apparatus of each limb was determined. Immediately before euthanasia, 6 of the 12 horses (thoroughbreds and standardbreds) had been engaged in active training or racing, and six horses in stall and/or pasture activity. In the actively training or racing horses, the point of acute failure of the suspensory apparatus was within the proximal sesamoid bones in 20 (83%) limbs (resulting in 17 apical fractures, 2 basilar fractures, an...
Moll HD, Slone DE, Humburg JM, Jagar JE.Three horses and three ponies were treated for traumatic luxation of the proximal intertarsal or tarsometatarsal joint. In each case, there were fractures of one or more tarsal bones. Three of the animals had disruption of one of the collateral ligaments. Five animals were treated by closed reduction and external coaptation. One pony was treated by open curettage, a cancellous bone graft, and cast immobilization. No internal fixation was used in any of these animals. From this series of cases, it would appear that closed reduction and external coaption alone is adequate treatment for most case...
Schamhardt HC, Merkens HW.A method was developed to quantify the ground reaction force pattern of the horse. A number of selected force amplitudes and peak-time positions in the normalized stance phase of left and right contralateral limbs were used to calculate symmetry indices. Data from each limb were compared with those of a 'standard horse' resulting in limb indices. The combination of amplitude and peak-time symmetry and limb indices yielded one H(orse)INDEX. These indices were useful for comparison of different horses and for the evaluation of lameness and treatment.
van Gurp M, Schamhardt HC, Crowe A.A model consisting of a spring loaded by a time-dependent mass is presented simulating the vertical and longitudinal horizontal ground reaction force patterns obtained from the hindlimb of a walking horse.
Hermans WA, Kersjes AW, van der Mey GJ, Dik KJ.A breeding experiment was carried out in a group of Shetland ponies in order to investigate the heredity of congenital lateral patellar (sub)luxation. A breeding herd was established and consisted of stallions and mares acquired at different times. Some were free from, and others were affected by lateral patellar (sub)luxation in either one or both femoropatellar joints. Over a period of 20 years, 49 foals were born from different mating combinations. Some offspring were free from the defect and others showed the abnormality. Though the number of foals bred during the experiment is rather smal...
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.
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.
Nixon AJ.An arthroscopic technique for examination and surgical treatment of conditions of the shoulder joint was evaluated in eight normal horses and two horses with osteochondrosis lesions. A single arthroscope entry point caudal to the infraspinatus tendon allowed inspection of the cranial, lateral, and caudal surfaces of the shoulder joint. With the humeral head and glenoid cavity distracted by a curved forceps, the entire cartilage surface of the shoulder could be examined. The caudomedial portion of the humeral head was seen better with a 70 degree angled arthroscope. Instruments for intra-articu...
Tew WP, Hackett RP.Synovial fluids from 72 equine joints were examined for the presence of cartilage debris, and these findings were compared to findings from visual inspection of the articular cartilage surfaces at necropsy. Synovial fluids from 25 joints with visual cartilage damage contained one or more large particles of articular cartilage. Cartilage fragments were not found in synovial fluids from 42 of the 47 apparently normal joints; thus, a correlation may exist between cartilage debris in the synovial fluid and lesions of the articular surfaces.
Anderson GF.The equine hoof and foot are the most commonly affected anatomic sites of lameness encountered during purchase examination of the performance horse. This article presents a thorough, systematic approach to the clinical evaluation of the hoof and foot relevant to the pre-purchase examination. Normal and abnormal conditions are discussed with reference to their potential effects on future performance and soundness. Proper trimming, balancing, and shoeing principles are emphasized.
Dzongowska-Dzongu T, Kotoński B, Hutny J.Alpha-1,4 leads to 1,4-glucosyltransferase preparations from horse muscles and serum were studied. The enzyme proteins from both tissues are very similar. Both proteins have a molecular weight of 240 000 and consist of four subunits of 60 000 daltons each. pH 5,0 is optimal for the activity. Only substrates with alpha-1, 4-linkages can serve as glucosyl donors for transferase reactions. Km values for both enzymes differ very slightly. At low substrate concentrations the hydrolytic activity can be found in addition to transferase reactions. At the concentration of the substrate higher than 40 m...
Oheida AH, Shalgum AA, Alrtib AM, Booker AO, Ben-Naser KM, Davies HMS.Carpal conformation is an important factor in relation to joint soundness. The equine carpometacarpal joint (CMCJ) was reported to have variations in its three palmaromedial articulations. Lacking one or more of these articulations has not been radiographically evaluated in Thoroughbred (TB) and Standardbred (SB) racehorses. The study aimed to identify the prevalence of the variation in the palmaromedial articulation of the carpometacarpal joint (PM-CMCJ) in TB and SB horses. Additionally, to detect the probability of having each of the three articulations within and between the breeds. Finall...
Pilsworth RC, Shepherd MC, Herinckx BM, Holmes MA.During a two year period, sagittal fractures of the wing of the ilium were diagnosed in 10 Thoroughbred horses. All were spontaneous fractures sustained during normal exercise in training and racing, with no history of inciting trauma. When ultrasound scans of the surface of the pelvis were performed, the fracture was clearly visible as a discontinuity of the sacral wing of the ilium. In 3 horses, an irregular contour suggestive of periosteal callus was seen in the vicinity of the acute fracture. All horses examined by gamma scintigraphy had a focal increase in uptake of isotope just lateral t...
Hartmann E, Baumgärtner W, Hungerland C.The present report describes the clinical and pathological findings of a one year old foal presented with paralysis of the hind legs. Macroscopically and histologically, a lymphosarcoma in the vertebral body and the adjacent epidural space of T 16, in the spleen and the mesenterial lymph nodes was observed. The adjacent spinal cord showed focal degenerative changes characterized by dilatation of myelin sheaths, swollen axons and few macrophages.