The metacarpal bone in horses is a key component of the equine forelimb, consisting primarily of the third metacarpal bone, commonly referred to as the cannon bone, and the smaller second and fourth metacarpal bones, known as splint bones. These bones provide structural support and play a vital role in weight-bearing and locomotion. The third metacarpal bone is the largest and most prominent, extending from the carpus (knee) to the fetlock joint. Its strength and integrity are essential for the horse's ability to perform various physical activities. The second and fourth metacarpal bones are positioned on either side of the third metacarpal and are remnants of evolutionary development. They can be involved in conditions such as splints, where inflammation occurs due to stress or trauma. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, function, and clinical aspects of metacarpal bones in horses, including their role in equine biomechanics and common pathologies.
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 ...
Sumner-Smith G, Bell M, Manley P, Caddell E, Hoare J.The advances made by the use of a telemetric system in the study of bone strain in a free-moving horse are reported. A rosette strain gauge was bonded to the craniomedial aspect of the metacarpus of the horse. Attachment of a miniature FM transmitter to lead wires facilitated telemetric transmission of of resistance changes which corresponded to limb movement. During 3 different gaits, the trace pattern remained similar, although frequency and amplitude varied. The tracings were similar to those reported in other species in which nontelemetric transmission was used.
Jones RD, Fessler JF.ALTHOUGH METACARPAL TI-IV and metatarsal II-IV (MC II-IV, MT II-IV) fractures are frequent in horses and surgical intervention routine, a review of the current literature revealed little information about this subject. The authors have found only two complete accounts of this problem (1, 6). The incidence of suspensory desmitis has been previously reported (3), but we find no previous correla-tion of MC II-IV, MT II-IV fractures with suspensory, desmitis. On these bases, a re-trospective study was conducted. At Purdue University from 1967 through 1974, 50 Standardbred horses underwent sur-gery...
Scott EA, Thrall DE, Sandler GA.Vascular supply of the equine forelimb was partially disrupted by ligation of the medial palmar and medial palmar digital arteries. Vascular architecture was evaluated before and after ligation by angiography. It was apparent from the present study that existing collaterals or newly formed collaterals, or both, were sufficient to maintain limb viability.
Turner AS, Milne DW, Gabel AA.Long-bone fractures of 6 foals admitted consecutively to the Ohio State University Veterinary Hospital were treated successfully with ASIF dynamic compression plating. The cases included 2 foals with closed fracture of the metacarpus, and 1 foal each with open nonunion of the metatarsus, closed fracture of the radius, open fracture of the tibia, and open fracture of the ulna. Five of these foals became sound, with no deformity, so they could be trained for racing or showing. The 6th foal, a filly with nonunion, became "pasture-sound" and was scheduled for breeding. It was concluded that the dy...
Milne DW, Turner AS, Gabel AA.In the horse, surgical approaches for plating fractures of the ulna, radius, metacarpus, tibia, and metatarsus involved a single curvilinear skin incision and incision of the superficial fascia in a manner to prevent postoperative dehiscence. The tension side of the bones, as well as location of nerves, arteries, veins, and muscles, were the major determinants in developing these approaches for atraumatic surgery and short operative time.
Hickman J.Sir Frederick Hobday's service as a Veterinary Officer in the Army Veterinary Corps during the Great War 1914-1918 is recorded. This is followed by a description of the fractures of the distal forelimb which can be treated satisfactorily by surgery, and includes fractures of the carpal, the small metacarpal, the proximal sesamoid bones, the first phalanx and the extensor process of the third phalanx.
Turner AS, Mills EJ, Gabel AA.Strain gauges were successfully bonded in vivo to the cranial, caudal, medial, and lateral aspects of the equine radium and tibia and to the dorsal, palmar, or plantar, medial, the lateral aspects of the metacarpus and metatarsus--all in the mid-diaphyseal region. Various activities were investigated, including walking, trotting or pacing, and standing up from anesthesia. The strain patterns showed that each stride produced a characteristic deformation cycle. The strains were measured and the axial loads were calculated as the horse performed certain activities. The tension band side of each b...
Sack WO.The nerve distribution to the digit of the horse was studied with the compound microscope in serial transverse sections of fetal limbs and plotted on life-size outlines of the horse's foot. It was learned that there is much variation in the topography of the branches of the principal nerves. There is no mirror-image nerve distribution on the 2 sides of the foot. The dorsal branch of the ulnar nerve does not extend below the fetlock. The communication between the palmar metacarpal nerves and branches of the dorsal branch of the digital nerves is only a crossing of nerves without exchange of fib...
Boorman S, Rodgerson DH.To report the outcome of foals treated for metacarpophalangeal varus deformity with a single-incision drilling technique for hemiepiphysiodesis of the distal lateral metacarpal physis. Methods: Retrospective case-control cohort study. Methods: Thoroughbred foals (n = 207), 171 age- and sex-matched maternal siblings. Methods: Medical records (2017-2020) were reviewed for signalment, limb(s) treated, location of the surgery, and any reported complications. Follow-up radiographs obtained for the yearling sale were assessed for abnormalities. Horses were matched to maternal siblings using an onl...
Hanie EA, Sullins KE, White NA.The results of 31 intracortical dorsal metacarpal stress fractures in 28 horses following unicortical osteostixis were reviewed. The incidence was predominately in the middle third of the lateral aspect of the left metacarpus, and males were affected more commonly. Approximately half of the surgical procedures were performed with the horse in the standing position. The mean times to return to training and racing were 4.25 and 6.9 months respectively. There was no correlation between time taken to return to racing and position of surgery. Complications experienced included lack of suture remova...
Thomas KL, Carmalt JL, Burnett WD, Arjmand H, Johnston JD.OBJECTIVE To compare strain at the bone-pin and cast-pin interfaces among 3 transfixation pin-cast constructs applied to equine forelimbs. ANIMALS 15 forelimbs from 15 adult horses. PROCEDURES Limbs were randomly assigned to 1 of 3 constructs. Centrally threaded positive-profile pins were used for all constructs, and the most distal pin was placed just proximal to the epicondyles of the third metacarpal bone. Construct 1 consisted of two 6.3-mm-diameter pins spaced 4 cm apart at 30° to each other. Construct 2 was the same as construct 1 except the pins were placed 5 cm apart. Construct 3 cons...
Keller SA, Valet S, Martens A, Weisse B, Fürst AE, Kümmerle JM. The aim of this study was to evaluate cyclic fatigue behaviour of a new pin with a thread run-out design in comparison with three other types of pins commonly used for equine transfixation pin casting. Methods: Twenty-four pairs of equine cadaveric third metacarpal bones (MC3) equipped with one transfixation pin placed horizontally in the distal metaphysis were tested using a simplified model, mimicking the biomechanical situation of equine transfixation pin casting. A 6.3/8.0-mm Imex Duraface pin with thread run-out design (ITROP) was compared with a 6.1-mm smooth Steinmann pin (SSP), a...
Whan G, Runciman RJ, Hurtig M.Whole bone in vitro biomechanical compressive testing can be complicated by three factors: sample asymmetry, heterogeneous material properties, and unknown effective centroid location. Methods: The technique presented here facilitates the calculation of effective centroid position, modulus of elasticity and equivalent uniform strain magnitude for a cross section of bone from a simple whole bone compressive test. Simplification of section response to load is achieved through a combination of linear beam and simple planer geometry theory. The technique requires three longitudinal strain gauges b...
Vidović A, Kuhn S.Fractures of the splint bones are the most common fractures in horses. Various treatment options for splint bone fractures (MC/MT II and IV), including conservative and surgical management, have been described. This report describes an acute splint bone fracture due to external trauma in a 17-year-old Icelandic mare. The fracture was diagnosed as an open multifragment fracture of the proximal third of the fourth metacarpal bone (MCIV) in the right front limb. Surgery was performed with the horse under general anaesthesia. The distal fragments were removed, and the distal part of the proximal r...
Hewitt-Dedman CL, Kershaw LE, Schwarz T, Del-Pozo J, Duncan J, Daniel CR, Cillán-García E, Pressanto MC, Taylor SE.Magnetic resonance spectroscopy (MRS) has been used to investigate metabolic changes within human bone. It may be possible to use MRS to investigate bone metabolism and fracture risk in the distal third metacarpal/tarsal bone (MC/MTIII) in racehorses. Objective: To determine the feasibility of using MRS as a quantitative imaging technique in equine bone by using the H spectra for the MC/MTIII to calculate fat content (FC). Methods: Observational cross-sectional study. Methods: Limbs from Thoroughbred racehorses were collected from horses that died or were subjected to euthanasia on racecourses...
Sweeney DM, Holmström M, Donohue KD, Lambert DH, Bayly WM.To describe the process whereby the screening of racing Thoroughbreds with accelerometer-based inertial measurement unit (IMU) sensors followed by clinical evaluation and advanced imaging identified potentially catastrophic musculoskeletal injuries in 3 horses. Methods: 3 Thoroughbred racehorses. Methods: All cases demonstrated an abnormal stride pattern either during racing (cases 1 and 2) or while breezing (case 3) and were identified as being at very high risk of catastrophic musculoskeletal injury by an algorithm derived from IMU sensor files from > 20,000 horses' race starts. Veterinary e...
van Veggel ECS, Vanderperren K, Selberg KT, Bergman HJ, Hoogelander B.This study evaluates the change in an MRI of the proximal metacarpal region in a group of sport horses that returned to work. This retrospective analysis evaluated 18 limbs represented by 17 horses. Results: The hyperintense signal within the dorsal collagenous part of the proximal suspensory ligament (PSL) on T1W/T2*W GRE sequences decreased or stayed the same in the majority of cases. The hyperintense STIR signal within the dorsal collagenous part of the PSL resolved in the majority of the patients, and the third metacarpal bone (McIII) hyperintense STIR signal resolved in all patients. The ...
Hoey S, Fogarty U, McAllister H, Puggioni A, Cloak B, Richard H, Skelly C, Laverty S.Articular cartilage can be directly imaged using ultrasonography. The fetlock is a common site of osteochondrosis, with the sagittal ridge of the third metacarpal bone most commonly affected. In osteochondrosis, cartilage thickening may be an initial finding. This postmortem study investigated the ability of ultrasonography to accurately measure the dorsodistal articular cartilage of the third metacarpal bone in young horses, compared to computed tomographic arthrography (CTA) and histological measurements. A total of 33 metacarpophalangeal joints from 18 horses between the ages of 12 days and...
Van Cauter R, Caudron I, Lejeune JP, Rousset A, Serteyn D.Osteochondral fragments within equine joints are commonly encountered and may predispose to lameness and limitation to sport purposes. Factors leading to this condition include genetic, nutritional and environmental conditions. However, few studies have evaluated the impact of conformation traits and their correlation with osteochondrosis. This study, based on the radiographic screenings of young horses born in Wallonia (266 individuals, 532 forelimbs), evaluated the correlation between foot, fetlock conformations of the front limb, height at the withers and presence of osteochondral fragments...
Son JK, De Paz P, Kim J, Sanaei R, Ryu S, Bailey S, Davies HMS.Changes in the third metacarpal (MC3) mid-diaphyseal dimensions were measured radiographically in young Thoroughbred racehorses through race training and found to be associated with a higher risk of shin soreness. However, it is still unclear whether such negative MC3 morphologies are set congenitally or through development. Objective: To quantify MC3 bone dimensional changes through growth. Methods: Longitudinal. Methods: Twenty privately owned Thoroughbred foals were radiographed bimonthly from birth to 14 months of age. Four linear MC3 parameters (proximodistal MC3 length, mid-diaphyseal do...
Kadic LIM, Liu CC, Leise BS, McCauley CT, Riggs LM.The aim of the study was to determine if a novel arthrodesis technique for the equine metacarpophalangeal (MCP) joint using a human non-contact bridging (NCB), polyaxial locking compression plate system has biomechanical and potential clinical advantages versus a traditional 5.5 mm stainless steel locking compression plate (LCP) under biomechanical testing. Methods: An ex vivo biomechanical equine cadaver study. Methods: A total of 11 MCP joints collected from adult Thoroughbred horses euthanized unrelated to musculoskeletal disease. Methods: Each pair of MCP joints were randomly implanted w...
Argue BJ, Labens R.Campdrafting is a unique Australian cow horse sport, which evolved from mustering cattle and is one of Australia's fastest growing equine sports. This discipline is associated with its own unique set of musculoskeletal injuries yet to be reported. Objective: To describe the prevalence, anatomical location, and diagnostic modality used to localise lameness in campdrafting horses to better assist efficient orthopaedic management of the campdraft horse. Methods: Retrospective case series. Methods: Medical records were examined from one private practice equine group and one university veterinary h...
Ruspi BD, Bramlage LR, Ruggles AJ, Slone SA.To report the rate of survival, rate of return to racing, and quality of racing performance following surgical fixation of medial condylar fractures. Methods: Retrospective study. Methods: A total of 150 Thoroughbred and Standardbred racehorses surgically treated for medial condylar fracture (100 lag screw fixation, 50 plate fixation). Methods: Medical records, radiographs, and racing databases (2000-2020) were reviewed to collect signalment, fracture characteristics, fixation methods, survival rate, and complication rate. Change in racing performance was assessed using Wilcoxon rank sum tests...
Eren G, López-Albors O, López Corbalán M, Latorre R.Digital technologies have improved the visualization of anatomical structures for veterinary education and clinical practice. In this study, a detailed three-dimensional anatomical model of the equine palmar metacarpal region was generated using E12-based epoxy sheet plastination combined with digital reconstruction in Amira V5.6 software. Serial cross-sections of the metacarpal region provided high-resolution visualization of bones, tendons, ligaments, nerves, vessels, fasciae, and synovial structures, with minimal shrinkage or deformation, ensuring improved anatomical accuracy. These section...
Folgmann MS, Stock KF, Feige K, Delling U.Current studies on the health status of young German Warmblood stallions are lacking. Objective: To evaluate the prevalence of radiographic findings at licensing examinations of Warmblood candidate stallions and quantify the environmental influences on the distribution of recorded findings. Methods: In this retrospective observational study, records of 1693 radiographic examinations performed on 1678 German Warmblood stallions presented for licensing in 2018-2020 were reviewed. Data were provided by all German Warmblood horse-breeding associations and their official veterinarians. The collecti...
Pan M, Malekipour F, Pivonka P, Morrice-West AV, Flegg JA, Whitton RC, Hitchens PL.Fractures of the distal limb in Thoroughbred racehorses primarily occur because of accumulation of bone microdamage from high-intensity training. Mathematical models of subchondral bone adaptation of the third metacarpal lateral condyles are capable of approximating existing data for Thoroughbred racehorses in training or at rest. To improve upon previous models, we added a dynamic resorption rate and microdamage accumulation and repair processes. Our ordinary differential equation model simulates the coupled processes of bone adaptation and microdamage accumulation, and is calibrated to data ...
Melly V, Ortved KF, Stewart HL, Stefanovski D, Richardson DW, Bubeck KA, Hogan PM, García-López JM.To present fracture cases selected for plate fixation (PF), describe surgical techniques and assess their association with postoperative complications and return-to-work outcomes in horses undergoing PF for small metacarpal/metatarsal (SMCT) fractures. Methods: Multicenter retrospective study. Methods: A total of 27 horses. Methods: Horses treated with PF of a SMCT fracture between 2008 and 2023 across three hospitals were included. Medical records and imaging were reviewed. Long-term outcomes were established by readmission to the hospital, telephone interviews, and/or race records. Univariab...
Shaw KA, Brounts SH.To evaluate the effect of heel elevation on measurement of stiffness gradients by means of acoustoelastography in the digital flexor tendons of clinically normal horses. Unassigned: 15 clinically normal horses. Unassigned: For each horse, stiffness gradient index (SGI) for superficial digital flexor tendons (SDFT) and deep digital flexor tendons (DDFT) were evaluated in both forelimbs at 0, 4 and 8 degrees of heel elevation. Acoustoelastography (AEG) was used for data acquisition at three sites, approximately 6, 12, and 18 cm distal to the accessory carpal bone in the metacarpal region. Lif...
Papini L, de Preux M, Pauwels F, Missotten J, Van der Vekens E.(1) Background: Cone beam computed tomography (CBCT) is increasingly used in equine practice to diagnose musculoskeletal injuries, including fractures in the distal limb. However, limited detail in the thick cortical bone of the metacarpus/metatarsus hinders accurate diagnosis. In human medicine, the addition of aluminum filters (AF) enhanced image quality while reducing radiation exposure. This study aimed to evaluate the effect of AF on image quality in CBCT scans of equine distal limbs. (2) Methods: Adult equine cadaver limbs were scanned with a mobile CBCT unit using varying tube currents ...
Malekipour F, Whitton RC, Muir P, Lee PV.Stress fractures are common in racehorses, with the metacarpophalangeal (MCP) joint being the most frequently affected site as it is subjected to high-magnitude and high-rate cyclic loads during training and racing. These loads lead to repeated compressive stresses, resulting in subchondral bone (SCB) sclerosis, fatigue microcracks, and matrix damage that can progress to parasagittal fractures or palmar osteochondral disease (POD). The present study developed joint-specific 3D FE models and slice-based FE models using standing CT images for three trained racehorses, each presenting distinct SC...
Harbowy RM, Nielsen BD, Colbath AC, Robison CI, Buskirk DD, Logan AA.Though circular exercise is commonly used in equestrian disciplines, it may be at the detriment of horses' musculoskeletal system. To investigate the effects of circular exercise on bone and joint health, 42 lambs were randomly assigned to a non-exercised control, straight-line, small circle, or large circle exercise regime at a slow (1.3 m/s) or fast (2.0 m/s) speed for 12 wk. Blood samples were taken biweekly. Animals were humanely euthanized upon study completion, and the fused third and fourth metacarpals were collected for biomechanical testing and bone density analysis. Fast groups were ...
