Metatarsal bones in horses are a group of long bones located in the hind limbs, extending from the tarsal bones to the phalanges. These bones play a role in supporting weight and facilitating locomotion. The equine metatarsus typically comprises the third metatarsal bone, also known as the cannon bone, and the second and fourth metatarsal bones, referred to as splint bones. The structure and health of these bones are significant for the overall mobility and performance of the horse. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, function, and clinical considerations of metatarsal bones in equine physiology.
Riggs CM, Whitehouse GH, Boyde A.This study examined 3-dimensional (3D) distribution of sectors with contrasting density in the equine third metacarpal (McIII) and third metatarsal (MtIII) bones with a view to explaining the aetiology of distal condylar fractures. Macroradiography and computed tomographic (CT) imaging were used in the nondestructive study of bones obtained from horses, most of which were Thoroughbreds in race training. Distal condylar regions of McIII and MtIII were also studied in microradiographs of 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces....
Riggs CM, Whitehouse GH, Boyde A.This study examined material from Thoroughbred horses, the majority of which had been in race training, for evidence of pathology in the third metacarpal (McIII) and third metatarsal (MtIII) bones which might be related to the occurrence of distal condylar fractures. Whole bone samples were studied and documented by macrophotography prior to macroradiography and computed tomographic (CT) imaging. Microradiographs were made from 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces of distal condylar regions of McIII and MtIII. Blocks were ...
Riggs CM.Fractures are the cause of considerable morbidity and mortality among Thoroughbred racehorses. A significant proportion of these injuries occur in the absence of any particular traumatic incident. Evidence of prefracture pathology interpreted as fatigue damage has been identified in some such cases, but the aetiology of many of these so-called 'spontaneous' fractures remains obscure. Parasagittal fractures of the third metacarpal (McIII) and third metatarsal (MtIII) bones are one of the more common fractures to affect Thoroughbred racehorses. The configuration of each of these fracture types i...
Wilmink JM, Stolk PW, van Weeren PR, Barneveld A.Second-intention healing of deep wounds was studied in 5 horses and 5 ponies. Standardised wounds were created on the distal limbs and hind quarters. Wounds on the metatarsi extended onto the metatarsal bone; the depth of the wounds in the femoral biceps muscle was 18 mm. The wound margins were marked by tattoos. Photographs were taken at weekly intervals to determine the wound area. The relative contribution of contraction and epithelialisation to wound closure was quantified by means of the tattoos. Swelling of the limbs was measured; and regularity and aspect of the granulation tissue were ...
McClure SR, Watkins JP, Glickman NW, Hawkins JF, Glickman LT.To compare treatments of complete fractures of the third metacarpal (MC) or metatarsal (MT) bone in horses and to identify factors that could impact prognosis. Methods: Retrospective case series. Methods: 25 horses with fractures of the third MC or MT bone that were treated by use of internal fixation, external coaptation, or both. Methods: Medical records from the Veterinary Medical Data Base of horses treated for fractures of third MC or MT bone at Texas A&M University from 1980 to 1994 and Purdue University from 1980 to 1996 were reviewed. Information on signalment, results of physical ...
Pearce SG, Firth EC, Grace ND, Fennessy PF.The effect of copper status on the evidence of bone and cartilage lesions was investigated in 21 Thoroughbred foals. The foals and their dams were grazed on pasture containing 4.4-8.6 mg Cu/kg dry matter (DM). Four treatment groups were created by randomly allocating mares and their foals to either copper supplemented (0.5 mg Cu/kg liveweight (LW)/day), or control (pasture only) groups. This experimental design allowed the effect of copper supplementation of mare and foal to be examined independently. Parameters of bone and cartilage development were assessed in the foals both in vivo, and at ...
Bassage LH, Richardson DW.To determine type, distribution, and radiographic appearance of condylar fractures of the third metacarpal bone (MC-3) or third metatarsal bone (MT-3) in Thoroughbreds (TB), Standardbreds (SB), and Arabians, to assess long-term outcome of horses in which fractures were repaired surgically, and to identify variables associated with prognosis for return to racing. Methods: Retrospective study. Methods: 224 horses with 233 fractures. Methods: Medical records and radiographs obtained before and after treatment were reviewed. Racing performance before and after treatment was determined by reviewing...
Roneus B, Arnason T, Collinder E, Rasmussen M.A clinical material of 133 Standardbred horses with palmar/plantar osteochondral fragments (POF) in the metacarpo- and metatarsophalangeal joints were studied. All horses had their fragments removed with arthroscopic surgery. 102 of the horses were 3 years old or younger when surgery was performed. Anatomical localisations of the fragments were in agreement with earlier reports. There was no statistical significant difference in month of birth in the POF--group compared to the total population. Eighty % of the horses that had raced before surgery came back to racing. The racing performance rel...
Ross MW.To correlate scintigraphic and clinical findings of the metatarsophalangeal joint (MTPJ) in Standardbreds, radiographic findings in horses with confirmed MTPJ lameness, and determine if stress reaction and more advanced bone remodelling occurred in the MTPJ, medical records of 114 Standardbreds admitted between September 1993 and April 1995 in which bone scintigraphy included standing lateral and plantar views of the metatarsophalangeal joint (MTPJ) were reviewed. Images obtained using a large field of view gamma camera were evaluated visually for location, definition and intensity of increase...
Bassage LH, Ross MW.Ten horses admitted for lameness evaluation including bone scintigraphy had enostosis-like lesions, described scintigraphically as focal or multifocal areas of intense increased radioisotope uptake within the medullary cavity of one or more long bones, and radiographically as one or multiple round to irregularly shaped radiopacities within the medullary cavity, often in close proximity to the nutrient foramen. There were 6 Thoroughbreds, one male, one female and 4 geldings, 3 Standardbreds, all geldings and one Appaloosa gelding; age 3-10 years. Enostosis-like lesions were seen in the tibia (5...
Cassotis NJ, Stick JA, Arnoczky SP.A 4-month-old Quarter Horse colt was admitted for repair of an open, comminuted fracture of the proximal portions of the diaphyses of the left second, third, and fourth metatarsal bones. Initial repair included internal fixation and cancellous bone graft. However, the third metatarsal bone became infected and failed to heal. After removal of infected portions of the bone, a 5-cm, fullthickness cortical allograft was placed in the defect. Rigid internal fixation provided stability for the allograft and remaining fracture fragments so that the horse was able to bear weight on the second and four...
Stiglhuber A, Breit S, König HE.The equine fetlock joint cavity shows ten pouches. The dorsal recess, which is oriented to the proximal side, is separated from those three pouches, which show to the distal direction, by several capsular folds. These folds are documented by means of sagittal sections through the fetlock joint. A medial/lateral recess is covered by the deep part of the collateral ligament of the fetlock joint. The collateral ligaments as well as the sesamoidean collateral ligaments are closely connected with the joint capsule, from which two capsular folds are separated. Between the part of the sesamoidean col...
Mair TS, Dyson SJ, Fraser JA, Edwards GB, Hillyer MH, Love S.The case records of 23 horses and one donkey affected by hypertrophic osteopathy (HO) (Marie's disease) were reviewed. All affected animals presented with limb swellings, which were bilaterally symmetrical and usually involved both fore- and hindlimbs. Associated signs included stiffness/lameness and weight loss. Radiological features included periosteal new bone formation over the diaphyses and metaphyses of affected bones. The metacarpal and metatarsal bones were most frequently affected. Articular surfaces remained free of disease. Seventeen animals were destroyed on humane grounds, 3 horse...
Johnston C, Roepstorff L, Drevemo S, Kallings P.Fast trotting Standardbred horses were filmed along a straight on an oval dirt track. Five consecutive stance phases were analysed to describe the planar kinematics of the distal hindlimb. The rapid changes in the geometry of the distal hindlimb that occur during the early stance phase were studied. The hoof segment was initially braked vertically and moved in the direction of the horse. The hoof moved forward on the track surface for more than 20% of the stance time (ST). Two specific deviations in the otherwise smooth course of the fetlock joint angle appeared at 16 and 29% of ST. Tarsal ang...
Bigot G, Bouzidi A, Rumelhart C, Martin-Rosset W.Two specimens (70.0 x 4.5 x 1.8 mm) (proximal and distal) of cortical bone were taken from each of the cranial, caudal, lateral and medial quadrants at mid-diaphysis of the third metacarpus and metatarsus of French saddle horses (12 males and seven females) aged from 1 day to 4 years. The mechanical properties (bending strength, Young's modulus, yield stress and ultimate specific deflection) were determined by a 4-point bending test, loading at a rate of 166 x 10(-6) ms-1. During growth, the mechanical properties of the cortical bone were not significantly different (p > 0.05) between metacarp...
Matthews GL, Keegan KG, Graham HL.To determine effects of tendon grip technique on in vitro surface strain measurements of equine deep digital flexor tendon (DDFT) when loaded in tension. Methods: 12 hind limb DDFT from 8 adult horses (mean age, 9.8 years [range, 4.5 to 17 years]; mean body weight, 472 kg [range, 450 to 509 kg]), with no clinical evidence of hind limb lameness. Methods: After calibration, liquid mercury strain gauges were sutured to plantar surfaces of the tendons at distal (position 1), middle (position 2), and proximal (position 3) metatarsal regions. Each tendon was affixed to a materials testing machine (d...
Dyson SJ, Arthur RM, Palmer SE, Richardson D.The gross and functional anatomy of the suspensory ligament (SL) and its ultrasonographic variability are described. Injuries of the suspensory apparatus are divided into lesions confined to the proximal one third of the metacarpus or metatarsus (proximal suspensory desmitis and avulsion fractures), lesions of the body, and branch lesions. Complete breakdown injuries are also discussed. In view of the close association of the SL, the second, third, and fourth metacarpal or metatarsal bones, and the proximal sesamoid bones, associated bony lesions are also considered.
Staller GS, Richardson DW, Nunamaker DM, Provost M.Contact area and pressure between 6-hole broad dynamic compression plates and 20 pairs of equine third metatarsal bones were measured using nonluted and luted plating techniques. Pressure-sensitive film (pressure ranges 10 to 50 MPa and 50 to 130 MPa) was used as the static pressure transducer. Nonluted and one of two luting techniques were tested on each pair of bones; each luting technique was tested on 20 bones. Quantitative determinations of contact area and pressure were made using computerized image processing techniques. Mean (+/- SD) total contact area for nonluted plates was 18.49% +/...
Hanson PD, Markel MD, Vanderby R.We evaluated the single-cycle structural properties for axial compression, torsion, and 4-point bending with a central load applied to the caudal or lateral surface of a diaphyseal segment from the normal adult equine humerus, radius, third metacarpal bone, femur, tibia, and third metatarsal bone. Stiffness values were determined from load-deformation curves for each bone and test mode. Compressive stiffness ranged from a low of 2,690 N/mm for the humerus to a high of 5,670 N/mm for the femur. Torsional stiffness ranged from 558 N.m/rad for the third metacarpal bone to 2,080 N.m/rad for the fe...
Crabill MR, Honnas CM, Taylor DS, Schumacher J, Watkins JP, Snyder JR.A review of medical records was used to identify 10 horses in which stringhalt developed subsequent to trauma to the dorsal metatarsus. Six horses developed stringhalt within 3 months after injury, 3 horses developed stringhalt > 3 months after injury, and time from injury to stringhalt was unknown for 1 horse. Horses were treated with exercise, including daily hand-walking with pasture turnout, followed by lunging; or surgically, using lateral digital extensor myotenectomy. Of the horses treated with exercise, 1 had resolution of stringhalt, 2 improved but had residual stringhalt, and 1 ha...
Hanson PD, Markel MD.As more sophisticated research is performed to refine fracture fixation techniques for horses, it is important that normal values for the geometric properties of the bones of the appendicular skeleton be determined and that suitable controls be available. We evaluated the geometric properties of total bone width, cortical bone width, and medullary canal/trabecular bone width measured from 2 radiographic projections of equine long bones (humerus, radius, third metacarpal bone, femur, tibia, and third metatarsal bone) obtained from a general population of horses. Measurements were performed on s...
Ellis DR.The common spontaneous fractures of the third metacarpus and
metatarsus of young racehorses are split cannons or condylar
fractures. Meagher (1976) described a series of 45 cases involving
the lateral condyle and Richardson (1984) detailed 15 cases involving
the medial metatarsal condyle. Rick et al. (1983) published a clinical
and pathological study of 75 cases of third metacarpal and metatarsal
condylar fracture. In the United Kingdom, Barr et al. (1989) recorded
8 cases with long fractures, 3 lateral and 5 medial condylar. This
paper reports 124 cases of medial or lateral condylar f...
van den Belt AJ, Dik KJ, Barneveld A.Over a 2 year-period, the ultrasonographic localization and distribution of flexor tendinous and ligamentous injuries, the long-term follow-up, and the outcome were studied in 101 Dutch Warmblood horses (DW) with a mean age of 8.7 years and in 71 Standardbred racehorses (ST) with a mean age of 5.2 years. The ratio between forelimb and hind limb flexor tendonitis/desmitis in the DW-group was 4:1 and in the ST-group group 4:3. In the DW-group, tendonitis/desmitis of the suspensory ligament (32%), the superficial digital flexor tendon (29%), the distal carpal check ligament (17%) of the forelimb ...
Dyson S.Proximal suspensory desmitis of the hindlimb was diagnosed using local analgesic techniques and ultrasonography in 42 horses. Subtarsal analgesia resulted in substantial improvement in lameness in 36 of 41 horses in which local analgesic techniques were used. In the remaining five horses lameness was improved by perineural analgesia of the tibial nerve (three) or the tibial and fibular nerves. Intra-articular analgesia of the tarso-metatarsal joint produced a similar degree of improvement in two of 24 horses in which lameness had been improved by subtarsal analgesia. Ultrasonographic abnormali...
Stolk PW, Firth EC.Eight metatarsophalangeal (fetlock) joints were studied in anaesthetized young ponies. Pressure measurements were made in the joint and at various sites in the marrow cavity of the third metatarsal bone with simultaneous measurement of systemic arterial and venous blood pressures. Fetlock joint flexion was always associated with a statistically significant initial decrease in intra-articular pressure (p < 0.05) followed by a marked increase in pressure (p < 0.05). Subsequent extension was accompanied by a similar pressure pattern, although there appeared to be a hysteretic relationship. ...
Beck C, Hitchens PL, Whitton RC.Post-mortem studies have shown that fractures involving the metacarpophalangeal/metatarsophalangeal or fetlock joint are associated with focal areas of microdamage. Identification of computed tomography (CT) features consistent with microdamage and their association with fracture may aid in identification of horses at risk of fracture. Objective: To identify CT features associated with fracture of the metacarpophalangeal/metatarsophalangeal joint. Methods: Retrospective cohort study. Methods: Post-mortem CT images of 367 limbs from 157 Thoroughbred racehorses were graded for CT features. Multi...
Ciamillo SA, Bills KW, Gassert TM, Richardson DW, Brown KA, Stefanovski D, Ortved KF.Stress-induced bone injury can lead to catastrophic injuries in Thoroughbred racehorses. Accumulation of high-speed exercise can increase the risk of subchondral bone injury. Objective: To investigate the effect of high-speed exercise on the subchondral bone of the metacarpo-metatarsophalangeal (MCP/MTP) joints using standing cone-beam computed tomography (CBCT) in young racing Thoroughbreds. Methods: Observational cohort study. Methods: Forty-one 2-year-old Thoroughbred racehorses during their first year of training were evaluated at 0, 6 and 12 months. Horses were evaluated for lameness an...
Caron JP, Barber SM, Doige CE, Pharr JW.This study documented the normal histologic features of the equine metacarpal and metatarsal periosteum and characterized its osteogenic response to surgical manipulation. Two periosteal flaps were elevated from the dorsomedial matacarpal and metatarsal diaphysis in each of three limbs of four yearling and four adult lightbreed horses. The superficial metacarpal cortex under the flap was resected with a bone chisel in one-half of the horses and was undisturbed in the remainder. One periosteal flap in each limb was excised and the other flap was replaced and secured by sutures. All limbs in the...
Stolk PW, Firth EC.Intra-osseous pressure measurements in the third metatarsal bone of anesthetised young and mature ponies demonstrated that a pressure gradient exists along the bone, the pressure being highest at the level of the nutrient foramen and decreasing distally and proximally from this point. The height of the intra-osseous pressure pulse also decreased toward the bone ends. It is concluded that the sites of measurement of the intra-osseous pressure in clinical and experimental studies should be standardized.
Meek DG, Dickinson EO.An illustrated approach to the medial aspect of the equine fetlock joint is described, whereby the collateral ligaments are transected. This approach is suggested as a possible technique for metatarsal or metacarpal bone fracture repair by retrograde pinning, arthrodesis of the fetlock joint and other joint and sesamoid bone surgery. The histological evidence of satisfactory healing is presented and the advantages and disadvantages are discussed.
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.
Gottschalk RD, Kirberger RM, Fourie SL.In order to establish the incidence of vacuum phenomenon in horses' carpal, metacarpophalangeal and metatarsophalangeal joints, stress-flexed radiographs were made of normal joints, joints with known pathology and in anaesthetised horses with joints under traction. Focal intra-articular radiolucencies were identified in normal stress-flexed carpal, metacarpophalangeal and metatarsophalangeal joints. These radiolucencies can be confused with those associated with pathological conditions.
Morisset S, Hawkins JF, Kooreman K.A 6-year-old Paint mare undergoing treatment for a degloving injury of the right metatarsus developed a non-weight-bearing lameness 19 days after admission. Diagnostic nerve blocks localized the source of pain to the area between the tarsus and the metatarsophalangeal joint. Radiography of the metatarsus and metatarsophalangeal joint, arthrocentesis of the metatarsophalangeal joint, and ultrasonography of the flexor tendons, flexor tendon sheath, and suspensory ligament failed to identify the cause of the lameness. The horse was anesthetized and intraosseous pressure was measured in the left a...
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...
Cassotis NJ, Stick JA, Arnoczky SP.A 4-month-old Quarter Horse colt was admitted for repair of an open, comminuted fracture of the proximal portions of the diaphyses of the left second, third, and fourth metatarsal bones. Initial repair included internal fixation and cancellous bone graft. However, the third metatarsal bone became infected and failed to heal. After removal of infected portions of the bone, a 5-cm, fullthickness cortical allograft was placed in the defect. Rigid internal fixation provided stability for the allograft and remaining fracture fragments so that the horse was able to bear weight on the second and four...
Updike SJ.Tendons of insertion of the equine tibialis cranialis muscle and peroneus tertius muscle (PT) were dissected grossly. Precise areas of tendon attachment and fiber arrangements within the tendons were described for the dorsal and medial tendons of the tibialis cranialis, and for the superficial lateral, deep lateral, dorsal, and medial tendons of the PT. Direct attachment of the dorsal and medial tendons of the PT into the periosteum of the central and 3rd tarsal bones and the 3rd metatarsal bone indicates that the PT may be involved in the pathogenesis of hock lamenesses.
Tscheuschner R, Richter W, Dietz O, Petersen R.Metacarpal or metatarsal exostoses were diagnosed in 112 horses used for sport purposes between January 1976 to December 1987. Fourteen of these patients were treated surgically by subperiosteal removal of the exostosis. All animals which could be followed up had returned to their original use. The average time of use after discharge from the clinic was 38.4 months. Surgery was successful in completely removing the exostoses in 58.3% of these horses. The indications for anaesthesia and resection of the ulnar nerve are discussed.
Pilsworth RC, Head MJ.The differential diagnoses of tarsal joint infection, fracture and peritarsal focal infection are of particular importance in practice. The objective of the present report is to provide additional clinical data to assist in the understanding of one of these conditions. The haematological parameters, clinical signs, treatment and outcome of 10 cases of severe lameness associated with peritarsal infection are reviewed. All horses had a significant rise in rectal temperature. The majority of cases (6/10) had haematological changes consistent with acute bacterial infection on the day of first exam...