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.
Stick JA, Wilson T, Kunze D.Of three horses with basilar skull fractures, two died within 48 hours. The remaining horse was euthanatized because of a locomotion deficit. Clinical signs included epistaxis followed by ataxia. In each case, the basi-occipital bone and ventral portion of the calvarium were involved in the fracture. Diagnosis was based on clinical signs or radiographic appearance of guttural pouches, or both.
Turner AS, Milne DW, Hohn RB, Rouse GP.Fracture of the capital femoral epiphysis occurred in three foals. One fracture was repaired by means of pinning under radiographic control and the two other fractures were repaired by means of trochanteric osteotomy.
Summers PM, Wells KE, Adkins KF.The features of an ossifying ameloblastoma in a 5-year-old gelding are described. The tumour developed in the angle of the right mandible and microscopically consisted of multiple follicles and islands of epithelial tissue adjacent to which were trabeculae of bone, osteoid and compact collagenous tissue.
Arnbjerg J.After a short review of previous literature about fractures of the navicular bone in horses, the symptoms and the pathological-anatomical changes of the condition are described. The most important clinical symptom is acute severe lameness without significant swellings, but with pronounced pain reaction to rotation of the coffin joint. After rest the lameness is reduced considerably, but without treatment it can persist for several years. Adherences between the deep flexor tendon and the site of the fracture and eventual damage to the coffin joint are considered to be the cause of the persistin...
Menard L, Marcoux M, Halle G.A case of unilateral front leg lameness with bone changes in the pedal bone suggestive of osteodystrophia fibrosa cystica is reported in an eight year old crossbred gelding. The changes were diagnosed at postmortem examination. The known possible causes are briefly reviewed.
Dik KJ.The radiological interpretation of periosteal new bone formation in the horse induced by trauma is described and illustrated by some casereports. The better the margins of the new bone can be defined the lesser the activity. The greater the density of the new bone, the longer the duration of time since injury.
Speirs VC, Wrigley R.Degenerative arthritis of the coxofemoral joints in the Norwegian Dole horse characterised by lameness, erosion of the joint cartilages, deposition of new bone at the attachments of the joint capsules and the teres ligaments, stretching and rupture of the teres ligaments and eventually luxation has been described and is considered to be due to hip dysplasia and to be inherited (Haakenstad, 1953). More recently there have been 2 reports of unilateral degenerative arthritis and subluxation in young horses (Jogi and Norberg, 1962; Davidson, 1967). In the last 8 years there have been 12,051 equine...
Scott EA, McDole M, Shires MH.Sixty-five cases of third phalanx (P3) fracture were retrieved from 20,638 case records at Michigan State University's Veterinary Clinical Center between Feb 1, 1964 and July 1, 1977. The fractures were classified by anatomic location, using a numbering system. Data from case records indicated the most common P3 fracture involved the articular surface of the coffin joint (53 of 65 cases; 81.5%). The greatest occurrence of P3 fracture was in Standardbreds (31 of 65 cases). Thirty-three of the 65 fractures were in geldings of all breeds; 57 of the cases were distributed among racing horses of fo...
Colles CM.In a survey of 95 control horses and 16 horses with navicular disease, the incidence of erosions and discoloration of the flexor cartilage of the navicular bone was no different between the control horses and those with navicular disease. All cases of navicular disease showed thrombosis of the distal navicular nutrient arteries and this could be related to a change to a rounded or flask shape of the distal nutrient foramen of the navicular bone. Erosions and discoloration of the navicular bone are therefore of no significance in navicular disease. Previously described lines of treatment are of...
Rose RJ, Taylor BJ, Bellenger CR.The technique of internal fixation of intra-articular fractures of the third phalanx using lag screw interfragmentary compression is described. Three cases are discussed and the successful treatment of infection and osteomyelitis described in one of them. Despite this potential complication internal fixation offers a better prognosis and also a more rapid return to work than non-operative treatments.
Bennett D.The gross and histological features of multiple bone infection in two foals are described. In both cases the lesions were confined to the region of the growth plate. Bone and, in some cases, growth plate cartilage destruction has occurred associated with an extensive inflammatory cell infiltration. The significance of the pathological observation is discussed in relation to the pathogenesis of bone infection in the foal.
Sage SE, Olive J, Lavoie JP.Age of complete ossification of equine occipital condyles has not been published. Consequently, clinical significance of occipital condyle defects on radiographs or CT scans of young horses remains unknown. The goals of this single-center, retrospective, cross-sectional study were to characterize incidental occipital condyle defects and to define the age of complete ossification. The margin of occipital condyles was classified as regular or with defect(s). Analyses were made on 121 horses, including 106 radiographic and 19 CT studies showing the occipital condyles of horses less than 5 years o...
Shields GE, Whitcomb MB, Vaughan B, Wisner ER.Injuries involving the femoral third trochanter are an uncommon but important source of equine lameness; however, clinical localization can be challenging. The purpose of this retrospective study was to describe ultrasonographic and scintigraphic findings in a group of horses with presumed third trochanter injury. Medical records of an equine referral hospital were searched from 2004-2014, and 20 horses met the inclusion criteria. Lesions consistent with third trochanter fracture were identified with ultrasound in 14/20 horses. Onset of lameness was acute (11), insidious (2), or unknown (1). A...
Bueno AC, Galuppo LD, Taylor KT, Jensen DG, Stover SM.To compare the mechanical shear strengths and stiffnesses obtained from in vitro testing of a simulated complete third carpal bone (C3) frontal plane radial facet slab fracture (osteotomy) stabilized with either a 4/5 Acutrak (AT) compression screw or a 4.5-mm AO cortical bone (AO) screw inserted in lag fashion. Drilling, tapping, and screw insertion torques, forces, and times also were compared between AT and AO implants. Methods: In vitro biomechanical assessment of site preparation, screw insertion, and shear failure test variables of bone screw stabilized simulated C3 slab fracture in pair...
Quinteros DD, García-López JM, Abuja GA, Tarkanian M, Maranda LS, Bubeck K, Kowaleski MP.To determine if the mechanical properties (strength and stiffness) of a new prototype 4.5 mm broad locking plate (NP-LP) are comparable with those of a traditional 4.5 mm broad limited-contact self compression plate (LC-SCP), and to compare the bending and torsional properties of the NP-LP and LC-SCP when used in osteotomized equine third metacarpal bones (MC3). Methods: The plates alone were tested in four-point bending single cycle to failure. The MC3-plate constructs were created with mid-diaphyseal osteotomies with a 1 cm gap. Constructs were tested in four-point bending single cycle to fa...
Rahm C, Ito K, Auer J.To compare acute fixation stability and insertion effort of cortex bone screws with and without a shaft inserted in lag fashion in equine metacarpal (metatarsal, MC(T)III) bone. Methods: Screw types with independent variables of screw diameter (4.5 or 5.5 mm) and shaft type (without shaft, with 20-mm shaft, or with 25-mm shaft) were studied. Bone specimens cut from distal equine MC(T)III condyles were used. After screw insertion in lag fashion into 2 bone blocks with an instrumented device, shear tests were conducted in a mechanical testing machine. Outcome variables of peak insertion torque, ...
Huber MJ, Grisel GR.An 18-month-old 450-kg [990-lb] sexually intact male Holsteiner was evaluated for lameness of the left forelimb of 3-months' duration. We were unable to localize the site of lameness, using intra-articular and perineural anesthesia, and radiography of the shoulder and cubital joint (elbow) did not reveal radiographic abnormalities. Nuclear scintigraphy was performed. An increase in radio-isotope uptake was evident at the lateral epicondyle of the left humerus. Radiographs of the region 3 weeks later revealed a 1.5-cm focal lucency surrounded by a 1.0-cm rim of necrotic bone. The lesion was con...
Firth EC.Detecting changes in bone during growth, training, rest from competition (spelling), and disease in horses requires imaging techniques that have a high level of accuracy and precision. Currently, most imaging techniques used in horses do not possess such characteristics and are more suitable for detecting end-stage disease than subtle changes. Some are incapable of detecting changes in bone size. Non-planar techniques should be used for estimating or determining bone strength. This review outlines available imaging techniques and shows why cross-sectional procedures are required to accurately ...
Vandeplassche M, Simoens P, Bouters R, De Vos N, Verschooten F.In 214 cases of severe dystocia in mares, of which 141 (66 per cent) were Draught horses, deviation of the head and neck, with or without torticollis, malformed head and limbs were found to be the cause of dystocia. No evidence of a genetic lethal factor was found and torticollis was often combined with scoliosis of the head and, frequently, with malformation of one or more limbs. This is considered evidence of a common aetiology and pathogenesis of the syndrome of malformation. The malformations were found to be associated with an increased incidence of caudal and, particularly, transverse pr...
Nixon AJ, Krook LP, Roth JE, King JM.A pulsed carbon dioxide laser was used to vaporize articular cartilage in four horses, and perforate the cartilage and subchondral bone in four horses. Both intercarpal joints were examined arthroscopically and either a 1 cm cartilage crater or a series of holes was created in the third carpal bone of one joint. The contralateral carpus served as a control. After euthanasia at week 8, the treated and control joints were examined for gross changes, and samples of cartilage and subchondral bone, synovial membrane, and peripheral lymph nodes were examined histologically. Depletion of cartilage ma...
Looijen MGP, Hanousek K, Maree JTM, Visser MC, Berner D.There is wide variability in radiographic grading systems in thoracolumbar spinous processes in horses. The aim of this study was to determine the agreement of grading different parameters, and combinations of those, in radiographs of the spinous processes of the equine thoracolumbar spine in the scope of a pre-purchase examination. We hypothesized that agreement is variable and interpretation of these radiographs is difficult. Methods: Radiographs of the thoracolumbar spine of healthy horses (N = 100) were assessed by three observers. Spinous processes were separately graded for interspinou...
Velásquez J, da Silva LLC, Miglino MA.There are many challenges in teaching veterinary anatomy, such as available classroom time, costs, and difficulties accessing animal cadavers, mainly due to animal welfare concerns. Furthermore, veterinary surgeons and radiologists complain that recent graduates lack anatomical knowledge. On the other hand, the current limitations of face-to-face teaching due to the COVID-19 pandemic suggest that the development of online distance education tools is necessary, mainly in specialties that lack this type of material. Teaching platforms promoting the integration of anatomy with other applied disci...
Carstanjen B, Amory H, Youssao I, Remy B.The purpose of this study was to validate an equine-specific osteocalcin (OC) radioimmunoassay (RIA) for use in donkeys and to establish age-related changes in serum OC concentrations in healthy donkeys. Serial dilutions of donkey serum showed parallelism with standard curves obtained with the equine-specific OC RIA. There was a tight linear regression between donkey serum OC values obtained with the equine specific OC RIA and a commercially available bovine-specific OC RIA. Serum OC levels of 27 healthy donkeys, analysed with the equine-specific OC RIA, showed a tight negative logarithmic reg...
Endo H, Nguyen ST, Yoshida M, Kudo K.The three-dimensionally real position and movement of the scapula in the lateral side of the ribcage could not be clarified in the horse, since the body size of the horse is too large to apply the CT scanning and image analysis methods. In this study, therefore, we examined the position and the movability of scapula using a carcass of the Falabella which is one of the smallest breeds of the horse. The whole skeletal system in thoracic part of the Falabella could be three-dimensionally observed by CT scanning method. The three-dimensional images show that the scapula cranially slides and the ve...
Bennett D.The gross and histological features of multiple bone infection in two foals are described. In both cases the lesions were confined to the region of the growth plate. Bone and, in some cases, growth plate cartilage destruction has occurred associated with an extensive inflammatory cell infiltration. The significance of the pathological observation is discussed in relation to the pathogenesis of bone infection in the foal.
Sod GA, Riggs LM, Mitchell CF, Martin GS, Gill MS.To compare number of cycles to failure for palmarodorsal 4-point bending of a modified 5.5 mm broad locking compression plate (M5.5-LCP) fixation with a 5.5 mm broad LCP (5.5-LCP) fixation used to repair osteotomized equine third metacarpal (MC3) bones. Methods: In vitro biomechanical testing. Methods: Adult equine cadaveric MC3 bones (n=6 pairs). Methods: An 8-hole, M5.5-LCP, obtained by having a 1.0 mm thickness removed from the bone contact portion of the 5.5-LCP, was applied to the dorsal surface of 1 randomly selected MC3 from each pair, and an 8-hole, 5.5-LCP was applied dorsally to the ...
Dyson S.The difficulties associated with the interpretation of the results of regional and intra-articular anaesthesia are discussed with reference to eight lame horses. The clinical and radiographic features of each horse are described, together with the results of anaesthesia. One horse had clinical and radiographic signs consistent with navicular disease but it was not possible to relieve the lameness. Two horses had fractures of bones within the foot but lameness was not improved by palmar (abaxial sesamoid) nerve blocks. One horse had more than one cause of lameness. Four horses had joint patholo...
Savage CJ, Tidd LC, Ostblom LC, Melsen F, Jeffcott LB.Histomorphometrical analysis of bone biopsies from the wing of ilium in 35 clinically normal horses are reported according to age. The biopsies were collected from 20 mixed-bred foals (mean age 6 +/- 1 months) and 15 older horses (mean age 73 +/- 62 months). No gender differences were found in the group of foals examined, but a significant difference (p less than 0.001) in a number of the primary measurements occurred between them and the older horses. The parameters which altered with age were the extent of osteoid surface (OS/BS), the extent of resorption (erosion) surface (ES/BS), the osteo...
Maggi R, Mudimba D, Marruchella G.A 11-year-old, Haflinger breed mare developed a slowly growing mass, protruding on the ventral aspect of the mandible. On palpation, the lesion was pedunculated, very firm, cold and not painful. Radiographic examinations showed a radiopaque, multi-lobular, "mushroom-like" lesion, which arose from the mandibular cortex without involving the bone marrow cavity. Thereafter, the mass was excised for cosmetic purposes. Microscopically, the lesion mainly consisted of bone trabeculae, covered by a thick layer of connective tissue resembling the periosteum. History and clinical findings allowed the te...
Gray AW, Davies ME, Jeffcott LB.We report on preliminary results of a novel in vitro culture system designed to generate equine osteoclasts in large numbers. Osteoclast generation, as determined by the expression of tartrate resistant acid phosphatase (TRAP) and ability to resorb bone, was enhanced in equine bone marrow cultures supplemented with fibroblastic cell (L929) conditioned medium (L929-CM). Bone marrow was collected from a total of 12 horses and ponies and TRAP-positive cells with bone resorbing ability were generated in significant numbers in the last seven. TRAP-positive mononuclear cells appeared after three day...
Sasaki N, Takakuwa J, Yamada H, Mori R.To evaluate effectiveness of allogeneic bone screws and pins for internal fixation of midbody transverse fractures of equine proximal sesamoid bones (PSBs) in vitro. Methods: 14 forelimbs from cadavers of 3-year-old Thoroughbreds. Methods: Allogeneic cortical bone fragments were collected from the limbs of a male Thoroughbred, and cortical bone screws were prepared from the tissue by use of a precision desktop microlathe programmed with the dimensions of a metal cortical bone screw. A midbody transverse osteotomy of each PSB was performed by use of a bone-shaping oscillating saw and repaired v...
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...
Fairburn AJ, Sherlock CE, Mair TS.Radiography is a standard diagnostic test for horses with suspected fractures of the palmar/plantar processes (PP) of the distal phalanx, however published studies evaluating the diagnostic utility for radiography are currently lacking. The objectives of this retrospective, diagnostic case-control study were to determine the sensitivity of radiographs for the detection of PP fractures, and determine the diagnostic utility of the palmar/plantar oblique projections of the PP for the identification of PP fractures compared to standard radiographic series. The medical records of horses undergoing...
Miyashita K, Suzuyama H, Chiba K, Osaki M, Mita H, Tamura N, Matsukawa M.For simple, safe, portable, and inexpensive evaluation suitable for leg bone diseases of racehorses in the field, an ultrasonic measurement technique was applied to evaluate wave velocities. A digital model of the third metacarpal bone with the bucked shin was fabricated using high-resolution peripheral quantitative computerized tomography data of a racehorse. This model was anisotropic and heterogeneous, and was constructed using the measured ultrasonic wave velocities in the bone. With this model, ultrasonic wave propagation along the bone axis was simulated using the elastic finite-differen...
Walencik-Łata A, Kozłowska B, Mietelski JW, Szufa K, Freire FD, Souza SO.This study aimed at assessing the incorporation of radionuclides in animals in the proximity of the uranium mine in Caetité, Brazil. In 2014, samples of bovine and equine teeth and skull bones were collected and their contents of natural and artificial isotopes were assessed using nuclear spectrometry techniques. Gamma ray emission from Ra and K isotopes was determined using high-purity germanium (HPGe) spectrometry, Sr radioactivity was measured with liquid scintillation, and U, Th, Po and Pu radioactivity was assessed with alpha-spectrometry. Prior to the measurements, sample dissolutions a...
Miyakoshi D, Senba H, Shikichi M, Maeda M, Shibata R, Misumi K.This study aimed to evaluate the influence of radiographic abnormalities of 2-year-old Thoroughbred horses that were listed at in-training sales in Japan, on whether they started to race or not at 2-3 years of age. Radiographs of 850 2-year-old Thoroughbreds in the in-training sales repository from 2007 to 2010 were reviewed, and 26 categories of radiographic abnormalities were found. Forty-three horses (5.1%, 43/850) did not start a race at 2-3 years of age. In accordance with the racing results for this age category, as determined by Fisher's exact test and multiple logistic regression analy...
Durket E, Kersh K, Dembek K, Riedesel E, Silverstone A, Kraus KH.To determine the influence of plate fixation (locking or dynamic compression) and the site of application (ventral [V] or ventrolateral [VL]) on the resistance to bending of transverse mandibular fractures. Methods: Ex vivo, simple randomized study. Methods: Mandibles harvested from adult equine cadavers (n = 18). Methods: Bilateral osteotomies were created 1 cm caudal to the mental foramen and perpendicular to the long axis of each mandible. Mandibles were fixed with 1 of 3 methods: (1) VL dynamic compression plate (DCP), (2) V-DCP, or (3) VL locking compression plating (LCP). Construct...
Wright IM, Smith MR.Removal of large chip fractures of the carpal bones and the osteochondral deficits that result, have been associated with a worse prognosis than removal of small fragments in similar locations. Objective: Reducing the articular defects by repair of large osteochondral fragments may have advantages over removal. Methods: Horses with osteochondral chip fractures that were of sufficient size and infrastructure to be repaired with small (2.7 mm diameter) AO/ASIF cortex screws were identified and repair effected by arthroscopically guided internal fixation. Results: Thirty-three horses underwent su...
Auer JA.Bilateral angular limb deformities of the metacarpo/metatarsophalangeal regions in 2 foals are discussed. Periosteal transection was used to correct the deformity in both foals. In one foal, only the right forelimb was treated because the deformity in the left forelimb did not appear to warrant surgery. Subsequently, an angular limb deformity, which could have been prevented, developed in the left forelimb. A third foal developed a deformity in the proximal phalanx after periosteal transection of the distal third metatarsal bone.
Caudron I, Grulke S, Farnir F, Vanschepdael P, Serteyn D.Adaptation of an in-foot shoe force sensor and the gait analysis system 'Fscan' makes it possible to monitor the distribution of the vertical forces under the equine foot in motion. The aim of this study is to investigate the effects of two different trimmings on forces under the foot during the trot. The first one increased the height of the lateral hoof wall and the second one restored the mediolateral balance of the foot. These two trimmings were examined by using a radiographical method that quantifies the interphalangeal articular asymmetries due to asymmetrical bearing. The location of t...
Henninger RW, Bramlage LR, Schneider RK, Gabel AA.Case records of 25 horses with transverse fractures of the proximal sesamoid bone were reviewed to evaluate the success of treatment. All fractures were repaired by use of lag screw fixation and an autogenous cancellous bone graft because the fracture fragments were considered too large for surgical removal and reconstruction of the suspensory apparatus was necessary. Radiography was performed in all cases, and the fractures were classified into 3 types: (1) proximal midbody fractures, which included all fractures in the proximal aspect of the sesamoid bone that resulted in fragments involving...
