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Topic:Tarsus

The tarsus, commonly known as the hock, is a complex joint located in the hind limb of horses. It consists of several bones, including the tibia, talus, calcaneus, and several smaller tarsal bones, which together form a hinge-like structure. The tarsus plays a significant role in locomotion by providing stability, support, and flexibility to the hind limb during movement. It is a frequent site of injury and various orthopedic conditions, such as osteoarthritis, bone spavin, and synovitis, which can impact a horse's performance and well-being. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, biomechanics, common pathologies, and treatment options associated with the equine tarsus.
Incomplete fracture of the talus secondary to maladaptive stress remodeling in a horse.
Journal of the American Veterinary Medical Association    June 14, 2019   Volume 255, Issue 1 102-108 doi: 10.2460/javma.255.1.102
Katzman SA, Spriet MP, Beck BR, Barrett MF, Hendrickson DA.A 6-year-old Quarter Horse gelding used for barrel racing was evaluated for acute onset of non-weight-bearing lameness of the left hind limb following strenuous exercise. Nuclear scintigraphic imaging revealed focal increased radiopharmaceutical uptake centrally within the left talus. Subsequent standard radiographic and ultrasonographic examinations of the tarsus failed to identify the cause of the increased radiopharmaceutical uptake; however, the lameness was definitively localized to the tarsocrural joint by intra-articular anesthesia. Subsequent MRI sequences of the left tarsus revealed a...
Prevalence, radiographic resolution and outcomes of slab fractures of the third and central tarsal bones in juvenile Thoroughbred horses.
Australian veterinary journal    March 29, 2019   Volume 97, Issue 4 108-115 doi: 10.1111/avj.12790
Steel CM, Collins VL, Hance SR, Adkins AR, Hitchens PL.Veterinarians are required to interpret the significance of radiographic findings for sale, soundness and future racing performance of weanling and yearling Thoroughbreds. We investigated the prevalence and radiographic appearance of slab fractures of the third (T3) and central tarsal (Tc) bones. Methods: Weanling and yearling horses with complete or incomplete T3 or Tc fracture were identified by searching a database of radiographs. The prevalence and radiographic appearance at initial diagnosis and after continued pasture turnout, as well as prognosis for racing, of fractures of T3 and Tc we...
Fragmentation of the dorsal distal aspect of the talus on weanling survey and pre-sale radiographs of juvenile Thoroughbreds: prevalence and 2- and 3-year-olds racing performance.
Australian veterinary journal    February 17, 2019   Volume 97, Issue 3 68-74 doi: 10.1111/avj.12787
Steel CM, Devery S, Hance SR, Adkins AR, Hitchens PL.Fragmentation of the dorsal aspect of the distal talus (FDDT), at the dorsolateral articular margin of the proximal intertarsal joint (PITJ) on pre-sale radiographs of yearling Thoroughbreds has not been previously described and data to support decisions made by veterinarians to predict future racing potential of horses with these lesions are lacking. Methods: In this retrospective case-control study we aimed to determine the prevalence of FDDT in juvenile Thoroughbreds and to report their race records. From a database of survey and repository radiographic examinations of 5709 horses, 36 with ...
The relationship between sagittal hoof conformation and hindlimb lameness in the horse.
Equine veterinary journal    December 15, 2018   Volume 51, Issue 4 464-469 doi: 10.1111/evj.13050
Pezzanite L, Bass L, Kawcak C, Goodrich L, Moorman V.Lameness can be multifactorial and may result from the accumulation of multiple seemingly unrelated causes. The identification of factors associated with lameness could be one method to decrease incidence of lameness and prolong the equine athlete's competitive life. Objective: To determine if there is an association between hoof balance in the sagittal plane and hindlimb lameness. Methods: Case-control study. Methods: Eighty client-owned horses with hindlimb lameness (cases) and 80 horses with no detectable hindlimb lameness (controls) were prospectively enroled following lameness evaluation ...
Effect of bandaging techniques on sub-bandage pressures in the equine distal limb, carpus, and tarsus.
Veterinary surgery : VS    August 22, 2018   Volume 47, Issue 5 640-647 doi: 10.1111/vsu.12914
Canada NC, Beard WL, Guyan ME, White BJ.To determine the influence of 3 types of bandages on sub-bandage pressures over the distal limb, carpus, and tarsus. Methods: Observational study. Methods: Eight healthy horses. Methods: Each of the 6 following bandages was applied on each horse in randomized order: (1) distal limb compression bandage (DLC), (2) double layer bandage (DL), (3) inner sanctum bandage (IS), (4) carpal compression bandage (CC), (5) tarsal compression bandage (TC), and (6) adhesive elastic carpal bandage (C-ELA). Sub-bandage pressures were measured with the Picopress compression measuring system (Microlab Electonica...
High field magnetic resonance imaging contributes to diagnosis of equine distal tarsus and proximal metatarsus lesions: 103 horses. Barrett MF, Selberg KT, Johnson SA, Hersman J, Frisbie DD.Injury of the distal tarsus and proximal metatarsus commonly causes lameness. Magnetic resonance imaging (MRI) allows concurrent assessment of both the distal tarsal joints and suspensory ligament origin, and aids identification of lesions that may otherwise go undetected by other modalities. In this retrospective observational study, the medical records of a veterinary imaging center were searched for MRI exams of the distal tarsus and proximal metatarsus for the years 2012 through 2014. Studies for 125 limbs of 103 horses were identified and retrospectively evaluated by two board-certified v...
Use of high-field and low-field magnetic resonance imaging to describe the anatomy of the proximal portion of the tarsal region of nonlame horses.
American journal of veterinary research    February 22, 2018   Volume 79, Issue 3 299-310 doi: 10.2460/ajvr.79.3.299
Biggi M, Dyson SJ.OBJECTIVE To use high-field and low-field MRI to describe the anatomy of the proximal portion of the tarsal region (proximal tarsal region) of nonlame horses. SAMPLE 25 cadaveric equine tarsi. PROCEDURES The proximal portion of 1 tarsus from each of 25 nonlame horses with no history of tarsal lameness underwent high-field (1.5-T) and low-field (0.27-T) MRI. Resulting images were used to subjectively describe the anatomy of that region and obtain measurements of the collateral ligaments of the tarsocrural joint. RESULTS Long and short components of the lateral and medial collateral ligaments of...
Gestation length and racing performance in 115 Thoroughbred foals with incomplete tarsal ossification.
Equine veterinary journal    July 20, 2017   Volume 50, Issue 1 29-33 doi: 10.1111/evj.12712
Haywood L, Spike-Pierce DL, Barr B, Mathys D, Mollenkopf D.Incomplete ossification of the cuboidal bones of the carpus and tarsus in foals has the potential for significant consequences including chronic lameness and decreased athletic ability. Objective: To determine if the degree of ossification of the cuboidal bones is associated with gestational length and if the diagnosis of incomplete ossification is a predictor of performance in Thoroughbred racehorses. Methods: Retrospective cohort study. Methods: The medical records of Thoroughbred foals less than 90 days of age from 1994 to 2011 were examined and records containing tarsal radiographs identif...
Rupture of the gastrocnemius muscle in neonatal thoroughbred foals: a report of three cases.
Journal of equine science    October 3, 2014   Volume 25, Issue 3 61-64 doi: 10.1294/jes.25.61
Sato F, Shibata R, Shikichi M, Ito K, Murase H, Ueno T, Furuoka H, Yamada K.Rupture of the gastrocnemius muscle is occasionally found in neonatal foals associated with dystocia and assisted delivery. In this report, 3 cases of gastrocnemius muscle disruption in newborn Thoroughbred foals (6, 5 and 2 days old) are reported. In all cases, the foals were presented with inability to rise unassisted postpartum, a dropped tarsus and swelling in the caudal aspect of the thigh accompanied by a hematoma. Ultrasonography, radiography, computerized tomography (CT) and subsequent autopsy were performed to confirm the clinical and pathological features of these cases.
Treatment of osteochondrosis dissecans in the stifle and tarsus of juvenile thoroughbred horses.
Veterinary surgery : VS    September 22, 2014   Volume 44, Issue 3 297-303 doi: 10.1111/j.1532-950X.2014.12277.x
Clarke KL, Reardon R, Russell T.To determine if arthroscopic surgery performed on weanlings/yearlings with trochlear ridge OCD of the femur (stifle OCD), or intermediate ridge of the tibia (tarsal OCD) detected on routine presale radiographs affects future racing performance. Methods: Retrospective case control study. Methods: Thoroughbred weanlings and yearlings. Methods: Stifle (N = 37; 22 male, 15 female) and tarsal (N = 35; 22 male, 13 female) OCD cases were identified. Outcome measures relating to racing performance (number of race starts, wins, places, and prize money earned, from races in their 2- and 3-year-old racin...
Morphologic and morphometric features of the calcaneal insertions of the superficial digital flexor tendon in the horse.
Veterinary and comparative orthopaedics and traumatology : V.C.O.T    August 4, 2014   Volume 27, Issue 5 366-371 doi: 10.3415/VCOT-14-03-0050
Barker WH, Wright IM.Accurate description of the calcaneal insertions of the superficial digital flexor tendon (SDFT) is lacking and inconsistent. The aim of this study was to undertake morphologic and morphometic evaluations of these structures to assist in elucidating their functional and pathogenic roles in displacement of the SDFT from the calcaneal tuber. Methods: Dissections were performed on 10 normal cadaveric hindlimbs. The anatomy was photographed to allow measurements at repeatable locations and differences in SDFT dimensions at the various locations were compared using a paired student t-test. Results:...
Plate fixation for management of plantar instability of the distal tarsus/proximal metatarsus in 5 horses.
Veterinary surgery : VS    January 27, 2014   Volume 43, Issue 4 425-429 doi: 10.1111/j.1532-950X.2014.12149.x
McCormick JD, Watkins J.To report plate fixation for management of traumatic injuries resulting in plantar instability of the proximal intertarsal (PIT) and tarsometatarsal (TMT) joints. Methods: Case series. Methods: Medical records (October 1988 to August 2007) of horses that had internal fixation of the distal aspect of the tarsus were reviewed. Horses that had a broad dynamic compression plate (DCP) or broad locking compression plate (LCP) applied on the plantar-lateral aspect of the tarsus extending from the proximal calcaneus to the proximal one third of the metatarsus were included. Signalment, clinical signs,...
Impact of walking surface on the range of motion of equine distal limb joints for rehabilitation purposes.
Veterinary journal (London, England : 1997)    December 11, 2013   Volume 199, Issue 3 413-418 doi: 10.1016/j.tvjl.2013.12.001
Mendez-Angulo JL, Firshman AM, Groschen DM, Kieffer PJ, Trumble TN.The aim of this study was to evaluate the effect of three footing surfaces on the flexion/extension, and range of motion (ROM) of the carpus, tarsus and fetlocks in the horse. The percentage of stride spent in the stance phase of sound horses at the walk was also measured. Nine sound horses were walked on hard ground (HD), soft ground (SF) and a land treadmill (LT), and five complete gait cycles were recorded by a digital video camera. Retro-reflective markers were placed on the skin at four anatomical locations on the left fore and hind limbs, and data were analyzed using two-dimensional (2D)...
Computed tomographic features of lesions detected in horses with tarsal lameness.
Equine veterinary journal    July 16, 2013   Volume 46, Issue 2 189-193 doi: 10.1111/evj.12097
Raes E, Bergman HJ, Van Ryssen B, Vanderperren K, Stock E, Saunders JH.Tarsal pain is a common cause of hindlimb lameness in horses. Diagnosis can usually be made with radiography and ultrasonography; however, in some cases, these techniques are inconclusive and additional imaging is necessary. No studies describing computed tomography (CT) features of different tarsal lesions in horses with tarsal lameness are reported. Objective: Our aims were as follows: 1) to characterise CT abnormalities in horses with tarsal lameness; 2) to compare CT findings with those from other imaging techniques; and 3) to assess whether CT can help to diagnose tarsal pathology. ...
Fragmentation of the proximal tubercle of the talus in horses: 9 cases (2004-2010).
Journal of the American Veterinary Medical Association    March 23, 2013   Volume 242, Issue 7 984-991 doi: 10.2460/javma.242.7.984
Espinosa P, Lacourt M, Alexander K, David F, Laverty S.To identify the prevalence of fragmentation of the proximal tubercle of the talus (FPTT) in a hospital population of horses, characterize the anatomic features of the affected area and fragments, and describe clinical findings, diagnosis, treatment, and outcome for horses with FPTT. Methods: Retrospective case series. Methods: 9 horses with FPTT. Methods: 2,543 radiographic views of the tarsal region of 1,526 horses that were evaluated between June 2004 and December 2010 were reviewed. Medical case records for horses with detectable FPTT were retrieved, and signalment, history, clinical signs,...
Magnetic resonance imaging of plantar soft tissue structures of the tarsus and proximal metatarsus in foals and adult horses.
Veterinary and comparative orthopaedics and traumatology : V.C.O.T    March 22, 2013   Volume 26, Issue 3 192-197 doi: 10.3415/VCOT-12-06-0072
Lempe-Troillet A, Ludewig E, Brehm W, Budras KD, Winter K, Edinger J.The object of this study was to describe previously defined soft tissue structures by using spin and gradient sequences in a 0.5 Tesla magnetic resonance system in order to improve the characterisation of tendon and ligaments at the plantar region of the equine tarsus and metatarsus while considering possible age-related variations. Methods: Cadaveric hindlimbs from twenty-two Warmblood horses with an age range from one month to twenty-five years were examined in spin and gradient echoes. The proximal suspensory ligament from six limbs was dissected to assign the signal intensities histologica...
Heritability estimates of tarsocrural osteochondrosis and palmar/plantar first phalanx osteochondral fragments in Standardbred trotters.
Equine veterinary journal    February 28, 2013   Volume 46, Issue 1 32-37 doi: 10.1111/evj.12058
Lykkjen S, Olsen HF, Dolvik NI, Grøndahl AM, Røed KH, Klemetsdal G.The pathogenesis of osteochondrosis (OC) and palmar/plantar first phalanx osteochondral fragments (POFs) is multifactorial, but specific knowledge of heritability is limited. Objective: To improve the precision of heritability estimates and to estimate the genetic correlation between tarsocrural OC and POFs in Standardbred trotters. Further aims were to examine whether the prevalence of OC/POFs was different in the American and French lineages that have contributed to the Norwegian population, and if the prevalence was affected by heterozygosity. Methods: Retrospective cohort study. Methods: C...
Clinical outcome of collateral ligament injuries of the tarsus.
The Canadian veterinary journal = La revue veterinaire canadienne    November 2, 2012   Volume 53, Issue 5 518-524 
Lamb L, Zubrod C, Hague B, Brakenhoff J, Major M.The significance of collateral ligament desmitis of the tarsocrural joint is often clinically underestimated, because it is an uncommon injury with a guarded prognosis for athletic soundness. The objective of this study was to describe the clinical presentation, treatment, and outcome of 12 horses with collateral ligament desmitis, along with tarsocrural joint synovitis secondary to hemarthrosis. Criteria for inclusion in this study included clinical signs of tarsocrural joint synovitis and sonographic evidence of collateral ligament desmitis. This retrospective study evaluated horses over an ...
Evaluation of intersegmental vertebral motion during performance of dynamic mobilization exercises in cervical lateral bending in horses.
American journal of veterinary research    August 2, 2012   Volume 73, Issue 8 1153-1159 doi: 10.2460/ajvr.73.8.1153
Clayton HM, Kaiser LJ, Lavagnino M, Stubbs NC.To identify differences in intersegmental bending angles in the cervical, thoracic, and lumbar portions of the vertebral column between the end positions during performance of 3 dynamic mobilization exercises in cervical lateral bending in horses. Methods: 8 nonlame horses. Methods: Skin-fixed markers on the head, cervical transverse processes (C1-C6) and spinous processes (T6, T8, T10, T16, L2, L6, S2, and S4) were tracked with a motion analysis system with the horses standing in a neutral position and in 3 lateral bending positions to the left and right sides during chin-to-girth, chin-to-hi...
Comparison of radiography, nuclear scintigraphy, and magnetic resonance imaging for detection of specific conditions of the distal tarsal bones of horses: 20 cases (2006-2010).
Journal of the American Veterinary Medical Association    April 21, 2012   Volume 240, Issue 9 1109-1114 doi: 10.2460/javma.240.9.1109
Daniel AJ, Judy CE, Rick MC, Saveraid TC, Herthel DJ.To describe pathological findings identified with MRI in the distal tarsal bones of horses with unilateral hind limb lameness attributable to tarsal pain and to compare the usefulness of MRI with that of radiography and nuclear scintigraphy in evaluation of this region. Methods: Retrospective case series. Methods: 20 lame horses. Methods: In all horses, MRI, radiography (4 standard projections), and nuclear scintigraphy of the tarsus had been performed. Horses were excluded if the results of all 3 imaging modalities were not available or if lameness was detected in more than 1 limb. Pathologic...
Evaluation of biomechanical effects of four stimulation devices placed on the hind feet of trotting horses.
American journal of veterinary research    October 26, 2011   Volume 72, Issue 11 1489-1495 doi: 10.2460/ajvr.72.11.1489
Clayton HM, Lavagnino M, Kaiser LJ, Stubbs NC.To compare effects of 4 types of stimulation devices attached to the hind feet on hoof flight, joint angles, and net joint powers of trotting horses. Methods: 8 clinically normal horses. Methods: Horses were evaluated under 5 conditions in random order: no stimulators, loose straps (10 g), lightweight tactile stimulators (55 g), limb weights (700 g), and limb weights with tactile stimulators (700 g). Reflective markers on the hind limbs were tracked during the swing phase of 6 trotting trials performed at consistent speed to determine peak hoof heights and flexion angles of the hip, stifle, ta...
Urinary glycosaminoglycans in horse osteoarthritis. Effects of chondroitin sulfate and glucosamine.
Research in veterinary science    September 16, 2011   Volume 93, Issue 1 88-96 doi: 10.1016/j.rvsc.2011.08.009
Baccarin RY, Machado TS, Lopes-Moraes AP, Vieira FA, Michelacci YM.Our objectives were to characterize the urinary excretion of glycosaminoglycans (GAGs) in horse osteoarthritis, and to investigate the effects of chondroitin sulfate (CS) and glucosamine (GlcN) upon the disease. Urinary GAGs were measured in 47 athletic horses, 20 healthy and 27 with osteoarthritis. The effects of CS and GlcN were investigated in mild osteoarthritis. In comparison to normal, urinary GAGs were increased in osteoarthritis, including mild osteoarthritis affecting only one joint. Treatment with CS+GlcN led to a long lasting increase in the urinary CS and keratan sulfate (KS), and ...
Comparison of cross-sectional anatomy and computed tomography of the tarsus in horses.
American journal of veterinary research    September 2, 2011   Volume 72, Issue 9 1209-1221 doi: 10.2460/ajvr.72.9.1209
Raes EV, Bergman EH, van der Veen H, Vanderperren K, Van der Vekens E, Saunders JH.To compare computed tomography (CT) images of equine tarsi with cross-sectional anatomic slices and evaluate the potential of CT for imaging pathological tarsal changes in horses. Methods: 6 anatomically normal equine cadaveric hind limbs and 4 tarsi with pathological changes. Methods: Precontrast CT was performed on 3 equine tarsi; sagittal and dorsal reconstructions were made. In all limbs, postcontrast CT was performed after intra-articular contrast medium injection of the tarsocrural, centrodistal, and tarsometatarsal joints. Images were matched with corresponding anatomic slices. Four tar...
Prevalence of radiographic changes in yearling and 2-year-old Quarter Horses intended for cutting.
Equine veterinary journal    August 5, 2011   Volume 44, Issue 2 185-195 doi: 10.1111/j.2042-3306.2011.00432.x
Contino EK, Park RD, McIlwraith CW.There have been many studies that document radiographic findings in young Thoroughbred and Standardbred horses. No such studies have been performed in Quarter Horses. Objective: To describe the prevalence of radiographic changes in the stifles, tarsi, carpi and fetlocks of young Quarter Horses intended for cutting. Methods: Radiographs of yearling and 2-year-old Quarter Horses were obtained from a radiograph repository and a private farm. The carpi, tarsi, fetlocks and stifles were evaluated and radiographic changes categorised by type and location. The frequency of changes was calculated and ...
Variation in frontal plane joint angles in horses.
Equine veterinary journal. Supplement    May 27, 2011   Issue 38 444-450 doi: 10.1111/j.2042-3306.2010.00192.x
Unt VE, Evans J, Reed SR, Pfau T, Weller R.Conformation in horses is often considered an indicator of athletic ability, performance and resistance to orthopaedic disease. Evaluation is performed in the standing horse and repeatability influenced by stance. Ground reaction forces increase in the moving horse as speed increases. Objective: To determine the effect of locomotion on equine carpus, tarsus, metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in the frontal plane. Objective: Valgus/varus angulation will change when moving. Methods: Kinematic data were collected standing, walking and trotting for 2 groups of horses. ...
Cross-sectional area of the tendons of the tarsal region in Standardbred trotter horses.
Equine veterinary journal    August 23, 2010   Volume 43, Issue 2 235-239 doi: 10.1111/j.2042-3306.2010.00141.x
Vilar JM, Santana A, Espinosa J, Spinella G.The assessment of a normal range for cross-sectional area (CSA) of tendons in the tarsal region is important in order to use them as reference values in the identification of pathological changes of dimensions. Objective: To provide normal reference values for the CSA of the tendons of the tarsus of Standardbred trotter horses (STH) by means of ultrasonography. Methods: Transverse echographic images of the tendons were obtained at different levels proximodistally; these images were digitised and CSA values (mean ± s.d.) were obtained for each structure. Results: The largest structure correspo...
Swing phase kinematic and kinetic response to weighting the hind pasterns.
Equine veterinary journal    August 23, 2010   Volume 43, Issue 2 210-215 doi: 10.1111/j.2042-3306.2010.00139.x
Clayton HM, Lavagnino M, Kaiser LJ, Stubbs NC.It is considered that specific exercises to strengthen limb musculature would be helpful. Objective: To describe swing phase kinematic and kinetic changes in the hindlimbs of trotting horses in response to the addition of leg weights to the hind pasterns. Methods: Six horses were prepared by placing reflective skin markers on the hindlimbs, the withers and fore hooves. Horses were evaluated at trot for 6 trials with and without leg weights (700 g) attached around the pasterns, with the 2 conditions applied in random order. The markers were tracked to determine peak heights of the flight arc of...
Epiphyseal cartilage canal blood supply to the metatarsophalangeal joint of foals.
Equine veterinary journal    April 14, 2010   Volume 41, Issue 9 865-871 doi: 10.2746/042516409x437762
Olstad K, Ytrehus B, Ekman S, Carlson CS, Dolvik NI.It is presently unknown whether cartilage ischaemia plays any part in the pathogenesis of osteochondral fragmentation within the equine metatarsophalangeal joint, as no detailed studies on microcirculation in the area have been reported. Objective: To describe the developmental pattern of the blood supply to the epiphyseal growth cartilage in the metatarsophalangeal joint of foals. Methods: Eight Standardbred foals were sacrificed between birth and age 7 weeks to undergo a barium perfusion procedure to demonstrate vessels within growth cartilage canals of one hindlimb. The metatarso-phalangeal...
Multiple osteochondral autografts for treatment of a medial trochlear ridge subchondral cystic lesion in the equine tarsus.
Veterinary surgery : VS    March 10, 2010   Volume 39, Issue 1 95-100 doi: 10.1111/j.1532-950X.2009.00576.x
Janicek JC, Cook JL, Wilson DA, Ketzner KM.To adapt the multiple osteochondral autograft technique for treatment of a subchondral cystic lesion (SCL) of the proximal medial trochlear ridge (MTR) of the equine talus and assess long term outcome. Methods: Case report. Methods: Quarter horse stallion with SCL of the proximal MTR of the talus. Methods: Osteochondral autograft techniques used in dogs and humans were adapted and optimized in equine cadavers. A horse with a SCL of the MTR of the talus was treated by osteochondral autografting. Three osteochondral autografts were harvested from the distal lateral trochlear ridge of the talus i...
Effect of exercise on thicknesses of mature hyaline cartilage, calcified cartilage, and subchondral bone of equine tarsi.
American journal of veterinary research    December 3, 2009   Volume 70, Issue 12 1477-1483 doi: 10.2460/ajvr.70.12.1477
Tranquille CA, Blunden AS, Dyson SJ, Parkin TD, Goodship AE, Murray RC.OBJECTIVE-To investigate effects of exercise on hyaline cartilage (HC), calcified cartilage (CC), and subchondral bone (SCB) thickness patterns of equine tarsi. SAMPLE POPULATION-30 tarsi from cadavers of horses with known exercise history. PROCEDURES-Tarsi were assigned to 3 groups according to known exercise history as follows: pasture exercise only (PE tarsi), low-intensity general-purpose riding exercise (LE tarsi), and high-intensity elite competition riding exercise (EE tarsi). Osteochondral tissue from distal tarsal joints underwent histologic preparation. Hyaline cartilage, CC, and SCB...