The skeletal system in horses comprises a complex structure of bones that provide support, protection, and mobility. Equine bones are involved in various physiological functions, including mineral storage and hematopoiesis. The bone structure in horses is categorized into different types, such as long bones, short bones, flat bones, and irregular bones, each serving specific roles in movement and stability. Research in this area explores topics such as bone development, remodeling, and the impact of nutrition and exercise on bone health. This page gathers peer-reviewed studies and academic articles that focus on the anatomy, physiology, and pathology of bones in horses, offering insights into conditions such as fractures, bone diseases, and the effects of aging on the equine skeletal system.
Milde AK.The objective of this study was to establish whether the carpal joints in horses are subject to development of arthrosis to a larger extent than previously assumed. Furthermore, an attempt has been made to clarify whether clinical diagnostical resources presently available are sufficient for accurate evaluation of the status in carpus. The present results show that an analysis of the synovia fluid is of little value in case of chronica arthrosis in carpus. Histilogical examination of the synovia membrane has been of limited value in this cases as it has not been possible to arrive at a definit...
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.
Easley KJ, Schneider JE.In 9 horses, osteotomies were performed to simulate accessory carpal bone fractures. Screw fixation, aided by a large C-clamp, was performed on 6 of the 9 horses. Three were treated conservatively, as controls, with fractures not repaired; they remained clinically lame throughout the 6-month study. Fibrocartilaginous nonunion developed in each of the 3 controls. At 150 days, the principals were free of lameness, with evidence of bony union. The results of clinical, radiographic, and pathologic evaluations showed surgical repair to be superior to prolonged rest in treating equine accessory carp...
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...
Webbon PM.The radiography of horses on behalf of a purchaser has become an inevitable part of a veterinarian's work. Radiography should, in theory, pose no more problems than a general clinical examination. In practice, difficulties arise when insufficient or inadequate films are taken or the films are misinterpreted. Radiographs of a diagnostic quality need to be taken and interpreted by a veterinarian who is reasonably well versed in radiological interpretation. Occasionally a lesion will be overlooked or misinterpreted and the radiographs will be retained so that the veterinarian's judgement can be c...
Dumas MB, Spano JS.Alkaline phosphatase isoenzymes of equine tissues, peritoneal fluid, and serum were characterized by their electrophoretic mobilities, using polyacrylamide gel disc electrophoresis. The alkaline phosphatase isoenzymes in liver, kidney, spleen, small intestine, placenta, bone, small colon, and large colon tissue samples were extracted and separated by electrophoresis. The resulting isoenzyme mobilities and spectrophotometric scans were evaluated for their tissue specificity and for their possible use in determining the tissue contribution of alkaline phosphatase to serum and peritoneal fluid. T...
Taylor TS, Vaughan JT.A study was conducted in an effort to explain why digital necrosis sometimes follows neurectomy in the horse. Six horses were subjected to unilateral section of the medial and lateral palmar nerves. Arteriography was done on each digit prior to surgery. Terminally, arteriography was repeated. Sections of bone, nerve, artery, skin, coronary band, and deep flexor tendon were examined histologically. Changes in arterial pattern and bone quality were noted. During the study, 2 of the horses had clinical signs of digital necrosis. The composite findings suggested trauma or infection, or both, of th...
Lean NE, Zedler ST, Van Eps AW, Engiles JB, Ford M, Stefanovski D, Walsh DM, Pollitt CC.Surgical stabilisation of the distal phalanx (DP) is a potential therapeutic strategy for severe acute laminitis. Objective: To evaluate the effects of locking compression plate (LCP) fixation of the DP to the dorsal hoof wall. Methods: Ex vivo and in vivo experiments. Methods: A T-shaped LCP was applied to one limb per pair in six pairs of cadaver forelimbs subjected to a combination of thermally induced lamellar failure and vertical load to simulate severe acute laminitis. Standard radiographic measurements were used to compare DP displacement. The LCP was then applied to one forefoot in 12 ...
Herdan CL, Nicholson CL, Firth EC.The third carpal bone (C3) responds to exercise by adaptive modeling of bone and articular calcified cartilage along the dorsal load path. Canals penetrating articular calcified cartilage, thought to contain vascular tissue, are reported in numerous species. Their significance remains unclear. Our objective was to determine if the number of canals was significantly different in strenuously exercised and control young horses and in a site of intermittent high loading compared to sites sustaining lower habitual loads. Volumetric bone mineral density in the radial facet of C3 of strenuously exerc...
Pye J, Kilcoyne I, Roy M, Vaughan B, Ormond C, Spriet M.A 20-year-old Quarter horse gelding was referred for evaluation of an acute onset non-weight-bearing right forelimb lameness. Marked soft tissue swelling was apparent over the right scapula and shoulder region; no crepitus was palpable. A complete transverse fracture of the scapular neck was suspected based on ultrasonography and radiographs were obtained to confirm the presumptive diagnosis. A complete, oblique fracture of the right scapular neck with mild cranial and proximal displacement of the distal fragment was detected. Computed tomography of the upper right forelimb was performed post-...
McD￮ LA, Stover SM, Bach JM, Taylor KT.To determine the mechanical properties of Equine Interlocking Nail (EIN; JD Wheat Veterinary Orthopedic Research Laboratory, University of California, Davis) stabilized osteotomized tibiae and compare these variables with estimated in vivo loads. Methods: In vitro biomechanical investigation. Methods: Twelve adult equine cadaveric tibiae. Methods: EIN-stabilized tibiae were tested monotonically under compression, 3- and 4-point bending, and torsion. Mechanical properties were compared with estimated in vivo loads. Results: EIN-tibial composite mean compressive yield load (11 kN) and bending mo...
Schoenborn WC, Rick MC, Hornof WJ.A 6-year-old Thoroughbred gelding presented with a left forelimb lameness. The results of lameness examination, radiography, nuclear scintigraphy, and computed tomography are presented. Based on the diagnostic imaging, subchondral fractures and osteochondritis dissecans lesions of the proximal articular surface of the proximal phalanx were diagnosed. A brief discussion of osteochondritis dissecans is presented.
Hollenbach E, Robert MP, le Roux C, Smit Y.If the number of events alone is considered, endurance riding is the fastest growing and the second-most popular Fédération Equestre Internationale (FEI) discipline. Lameness is the most common cause of elimination from endurance races worldwide. To the authors' knowledge, no studies have been published investigating the prevalence of radiographic changes in the forelimb digits and metacarpophalangeal joints (MCP) of endurance racehorses in South Africa. Unassigned: Investigate the prevalence of radiographic changes in the forelimb digits and MCP joints of South African endurance racehorses....
Komosa M, Włodarek J, Dzierzęcka M, Nienartowicz-Zdrojewska A, Tołkacz M.The problem of navicular bone lesions is better understood in warmblood horses. The aim of our research was to compare pathologic lesions of navicular bone of different types of horses divided into age groups. An extra goal was to compare radiographs with anatomical status of navicular bone dissected from the hoof capsule. The study group included 161 horses, out of which 100 individuals were warmbloods, and 61 - coldbloods. In total 280 navicular bones were analysed. The flexor surface, distal border fragments, enthesophytes and the process of obliteration of nutrient foramina were analysed. ...
Mageed M, Elfadl A.An 18-year-old Quarter Horse mare was evaluated because of moderate left forelimb lameness of 4 weeks' duration. The clinical evaluation and diagnostic perineural analgesia localized the lameness to the distal portion of the left forelimb. There was swelling on the dorsal and lateral aspect of the coronary band. Radiography, ultrasound, magnetic resonance imaging, and computed tomography of the foot revealed circumscribed well-capsulated soft tissue mass causing a focal deformation of the dorsolateral border of the middle phalanx. The treatment aimed to remove the mass surgically and stabiliz...
Lee S, Lee EB, Park KW, Jeong H, Shin KY, Kweon YP, Seo JP.The equine temporomandibular joint (TMJ) has a complex anatomical structure that makes diagnosis of TMJ disorders difficult. Computed tomography (CT) is now available in equine medicine; hence, TMJ evaluation has become more convenient. Objective: The objectives of this study were to describe the CT features of the TMJ in Jeju horses and to compare these features with those of Thoroughbreds. Methods: In this report, the TMJs of 10 Jeju horses (mean age: 4.5 ± 1.9 yr; mean body weight: 282.6 ± 40.3 kg) and 6 Thoroughbreds (mean age: 7.3 ± 1.6 yr; mean body weight: 479.7 ± 44.0 kg) were exam...
Mundy LN, Lescun TB, Main RP, Hall Griffin T.To compare heat generation and mechanical bone damage achieved with 2 tapered and 1 cylindrical transfixation pin taps in third metacarpal bones from equine cadavers. Methods: 18 pairs (36 specimens) of third metacarpal bones from euthanized horses with no known metacarpal disease. Methods: In each bone, an investigator drilled 3 holes for placement of a 6.3-mm cylindrical transfixation pin, a 6.3-mm tapered pin using a prototype tapered tap, and a 6.3-mm tapered pin using a revised tapered tap. One bone of each pair was tapped by hand and the other with an electric drill. Temperatures of the ...
Lloyd KC, Koblik P, Ragle C, Wheat JD, Lakritz J.In 4 adult horses, simple, nondisplaced, incomplete fracture of the proximal extremity of the third metacarpal bone (MC3) was identified radiographically only on the dorsopalmar projection. Lameness was slight to moderate. Although nerve blocks of the foot and fetlock did not alter the lameness, high palmar regional nerve block improved the gait in 1 of the 2 horses on which it was performed. Pain on palpation or swollen distal accessory (inferior check) ligament, flexor tendons, and suspensory ligament were not found in any horse. The fracture was localized to the palmar surface of the proxim...
Brokken MT, Schneider RK, Tucker RL.To describe a surgical approach for the removal of nonarticular base sesamoid fragments in performance horses and to report the outcome. Methods: Retrospective study. Methods: Horses (n=11), 7 months to 10 years of age, with lameness because of nonarticular base sesamoid fragments. Methods: Lameness was localized to the metacarpophalangeal/metatarsophalangeal region by clinical examination or response to diagnostic local anesthesia. Radiographs confirmed the diagnosis of a nonarticular base sesamoid fragment. Surgical removal was performed with an incision over the base of the affected sesamoi...
Rose PL, Hightower D, Auer JA, Hulse D, Schenk RK.In the present study, radionuclide scintigraphy and radiography were used to evaluate the rate and degree of healing that occurred in surgically created subchondral bone defects in horses. Following radionuclide scintigraphy and radiography the horses were killed, and histomorphometric analysis was performed on the defect sites. The histomorphometric results were compared to the radionuclide scintigraphic and radiographic results to determine which noninvasive technique provided the most accurate information concerning healing of the bone defects. It was concluded that radionuclide scintigraph...
Vinardell T, David F, Morisset S.To describe a direct arthroscopic approach to the suprapatellar pouch (SPP), its intra-articular anatomy, and report our clinical experience with SPP arthroscopy. Methods: (1) Experimental study and (2) retrospective clinical study. Methods: (1) Cadaveric equine hind limbs (n=24; 14 horses) and (2) 5 horses. Methods: Four femoropatellar joints (FPJ) were dissected or injected with latex to document surface landmarks and topographic anatomy. (1) Arthroscopic exploration of 20 SPP (10 equine cadavers) was performed and described, followed by dissection. (2) Medical records of horses that had FPJ...
Elzer EJ, Bramlage LR.Outcomes have been reported for a limited number of short frontal plane fractures of the proximal phalanx following nonsurgical treatment and internal fixation. Objective: To describe a new approach, arthroscopic debridement, of short frontal plane fractures of the proximal phalanx in flat-racing Thoroughbreds and post-operative racing outcome. Methods: Retrospective case-control study. Methods: Medical records of 81 Thoroughbred racehorses treated with arthroscopic debridement for frontal plane fractures of the proximal phalanx were reviewed. Diagnostic images and operative reports were used ...
Booth AD, Hidalgo FL, Bellezzo F, Young JM, Bianco AW, Hughes LE, Maher M, Trumble TN, Ernst N.To describe outcomes of horses with temporohyoid osteoarthropathy (THO) treated with partial ceratohyoidectomy. 10 client-owned horses. Medical records from 2 institutions were examined for records of horses with THO treated with partial ceratohyoidectomy between 2010 and 2021. History, signalment, clinical signs, diagnostics, medications, and surgery-related details were recorded. Horses with a minimum of 6 months follow-up were recruited for neurologic and imaging examinations in the hospital or field where radiography of the basihyoid-ceratohyoid articulation were performed along with CT, w...
Collier MA, Brighton CT, Rendano VT, Schryver HF, Kallfelz FA.Electrically induced osteogenesis exhibits a dose response curve and can induce bone formation in the absence of trauma and in nonunions. Electrically induced osteogenesis, using direct electric current (DC) in a third metacarpal diaphyseal osteotomy model, in conjunction with internal fixation and postoperative loading, was investigated. Twelve young adult ponies of mixed sex were divided into 2 treatment groups (A and B) of 3 stimulated and 3 controls each and evaluated, using a specifically designed procedure. Stimulated ponies in both groups were given 20 microA of DC via an implanted bone...
Beinlich CP, Nixon AJ.In this study, the radiographic and histologic appearance of lateral palmar intercarpal ligament (LPICL) avulsion in the horse was characterized. Thirty-seven horses with radiographic evidence of avulsion fragments originating from the medial palmar aspect of the ulnar carpal bone were examined. The dorsolateral to palmaromedial projection was useful for evaluating the size and shape of the avulsed bone fragment, and the dorsopalmar projection added information on the relative proximity of the fragment to its fracture bed. Radiographic features that differentiated LPICL avulsion from subchondr...
Booth TM.Severe, chronic lameness in the left forelimb of a five-year-old Arab stallion was localised to the bicipital bursa by local anaesthesia and gamma scintigraphy. Radiographic and ultrasonographic examinations of the proximal humeral tubercles and bicipital bursa revealed new bone production in the region of the intertubercular grooves and irregularities in the density of the soft tissues of the bicipital tendon and bursa. An endoscopic examination of the bicipital bursa with a standard arthroscope under general anaesthesia was a useful diagnostic procedure. The stallion was euthanased, and mark...
Busschers E, Richardson DW, Hogan PM, Leitch M.To describe the characteristics of unilateral mid-body proximal sesamoid bone (PSB) fractures, to determine factors associated with the outcome of horses after surgical repair, and to describe a technique for arthroscopically assisted screw fixation in lag fashion. Methods: Retrospective case series. Methods: Horses (n=25) with unilateral mid-body PSB fracture. Methods: Medical records (1996-2006), radiographs, and arthroscopic videos of horses with surgically repaired unilateral mid-body PSB fractures were reviewed. Retrieved data included signalment, affected limb and PSB, fracture character...
Carstanjen B, Sulon J, Banga-Mboko H, Beckers JF, Remy B.This study describes for the first time the development and validation of a sensitive and specific radioimmunoassay (RIA) for equine osteocalcin (OC) quantification using purified equine OC as standard, tracer, and immunogen for antibody formation in rabbits. The assay allowed to measure equine serum OC levels with a sensitivity of 0.2 ng/mL. Immunoreactive serum OC values of clinically normal, different-aged horses ranged from 3.68 to 127.31 ng/mL. Intra- and inter-assay coefficients of variation (CV) were 6.2 and 8.2%, respectively. Serial equine serum sample dilutions were linear. The recov...
Zweers AD, Dik KJ.The radiographic diagnostic value of Rose's palmaroproximal-dorsodistal ('skyline') projection and Oxspring's dorsopalmar projection of the equine navicular bone were compared, by examining radiographs of 102 navicular bones originating from 66 randomly selected horses with clinical evidence of lameness located in the navicular area. In 27 navicular bones essential information was obtained from the skyline view, 15 independently of Oxspring's projection and 12 in addition to this view. For 11 navicular studies the D.P. projection was the most important diagnostic view. In the other 64 navicula...
Pilsworth RC, Holmes MA, Shepherd M.A fracture of the pelvis in a horse can be detected scintigraphically by probe point counting. However, the pelvis is covered by a large and variable muscle mass, and is close to the urinary bladder, both of which can introduce errors. This paper describes an improved technique which uses a larger set of sampling points and analyses the data with a small computer to construct a three dimensional graph of the gamma-ray output across the pelvis, thus helping to improve the interpretation of the data. The scintigraphic plot from a normal horse, three cases of fracture (confirmed by radiography, u...
Barr AR.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...
Denny HR.The current trends in equine fracture treatment are reviewed. Surgical approach, method of fixation, the advantages of Association for the Study of Internal Fixation (ASIF) implants and the complications of treatment are discussed with reference to 21 fracture cases. Normal limb function was restored in four horses with fractures of the olecranon and one with a mid shaft fracture of the tibia following stabilisation of the fracture with plates. A horse with a chip fracture of the distal radius and three other animals with fractures of the lateral condyle of the third metacarpal bone were also ...
Seltzer KL, Stover SM, Taylor KT, Willits NH.The torsional monotonic structural material properties of equine metacarpi with or without, either a 5/16 inch or 3/8 inch diameter bicortical lateromedial middiaphyseal hole were assessed to determine the effect of a hole on metacarpal strength. Torsional stiffness was not significantly effected by the presence of a bicortical hole, whereas yield and failure angles, torques and energies of metacarpi with a hole were 51% to 97% of those of intact bones. Significant differences were not apparent for yield and failure mechanical properties between metacarpi with a 5/16 inch diameter hole and met...
Harrington DD.1. The effects of feeding with a purified magnesium-deficient diet (--Mg, 7-8 mg Mg/kg) on horse foal blood serum and tissue concentrations of Mg, calcium and phosphorus were studied, and the results compared with histopathological findings. 2. Serum concentrations of Ca and P were unaffected by feeding with the --Mg diet, whereas serum Mg concentrations decreased from a mean initial (day o) concentration of 0.78 mmol/l to 0.53 mmol/l 7 d after foals were placed on the -Mg diet, and then continued to decrease at a slower rate. 3. Aorta concentrations of Ca and P, but not Mg, were positively co...
Németh F.The aetiology and pathogenesis of navicular bone disease and sesamoidosis are discussed on the basis of findings reported in the literature and research. A marked similarity is found to be present between the clinical presentation, aetiology and pathogenesis of these two diseases. In addition, the intra and juxta-articular signs of degeneration as seen in these diseases are similar to those seen in various forms of arthrosis. Circulatory disturbances resulting from partial or complete arterial occlusion, caused by arteriosclerosis, are likely to play an important role in the cause of degenerat...
Ehrlich PJ, Dohoo IR, O'Callaghan MW.To document anatomic patterns of scintigraphic uptake and related orthopedic disease associated with racing activity in Standardbred horses. Methods: Retrospective study. Methods: 64 Standardbred horses evaluated for lameness. Methods: Medical records at the time of discharge were reviewed, and information regarding signalment; history; results of lameness examination, scintigraphy, and radiography; diagnosis; and treatment were obtained. Results: 274 areas of increased radiopharmaceutical uptake were identified. Scintigrams of 218 limbs (106 forelimbs, 112 hind limbs) were available for revie...
Sod GA, Mitchell CF, Hubert JD, Martin GS, Gill MS.To compare monotonic biomechanical properties and fatigue life of a 5.5 mm broad limited-contact dynamic compression plate (5.5-LC-DCP) fixation with a 4.5 mm broad LC-DCP (4.5-LC-DCP) fixation to repair osteotomized equine third metacarpal (MC3) bones. Methods: In vitro biomechanical testing of paired cadaveric equine MC3 with a mid-diaphyseal osteotomy, stabilized by 1 of 2 methods for fracture fixation. Methods: Adult equine cadaveric MC3 bones (n=18 pair). Methods: MC3 were divided into 3 test groups (6 pairs each) for: (1) 4-point bending single cycle to failure testing; (2) 4-point bendi...
